[Rails] What is the question mark inside this regex doing?
I thought the ? matches zero or one occurrence of a pattern. However in
this example:
def show_regexp(string, pattern)
match = pattern.match(string)
if match
#{match.pre_match}-#{match[0]}-#{match.post_match}
else
no match
end
end
a = The moon is made of cheese
show_regexp(a, /\s.*?\s/) #= The- moon -is made of cheese
What exactly is the ? doing?
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[Rails] capistrano: deploying production and staging to same database
I have the production and staging site on two different server ips. But the database, another server ip, is the same database used by both production and staging. When i set up the capistrano deploy task for both the production and staging, should I keep the db role in deploy.rb like this: deploy.rb role :db, database_ip, :primary = true production.rb role :web, production_ip role :app, production_ip staging.rb role :web, staging_ip role :app, staging_ip Or should I do it this way: production.rb role :web, production_ip role :app, production_ip role :db, database_ip, :primary = true staging.rb role :web, production_ip role :app, production_ip role :db, database_ip, :primary = true -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/rubyonrails-talk/f4494c9d-b537-4e7e-b92f-b50f56520870%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
[Rails] staging server unexpectedly started installing gems during staging deploy
I have a production server and a staging server and a production git
branch and a staging git branch for the same repository on github. The
production git branch and staging git branch are identical. I got my
staging server running and during the second deploy, something unexpected
started happening:
...
** [out :: xxx.xx.xx.xxx] Installing multi_json (1.5.0)
** [out :: xxx.xx.xx.xxx]
** [out :: xxx.xx.xx.xxx] Installing activesupport (3.2.5)
** [out :: xxx.xx.xx.xxx]
** [out :: xxx.xx.xx.xxx] Installing builder (3.0.4)
** [out :: xxx.xx.xx.xxx]
** [out :: xxx.xx.xx.xxx] Installing activemodel (3.2.5)
** [out :: xxx.xx.xx.xxx]
** [out :: xxx.xx.xx.xxx] Installing erubis (2.7.0)
** [out :: xxx.xx.xx.xxx]
** [out :: xxx.xx.xx.xxx] Installing journey (1.0.4)
** [out :: xxx.xx.xx.xxx]
** [out :: xxx.xx.xx.xxx] Installing rack (1.4.1)
** [out :: xxx.xx.xx.xxx]
** [out :: xxx.xx.xx.xxx] Installing rack-cache (1.2)
** [out :: xxx.xx.xx.xxx]
** [out :: xxx.xx.xx.xxx] Installing rack-test (0.6.2)
** [out :: xxx.xx.xx.xxx]
** [out :: xxx.xx.xx.xxx] Installing hike (1.2.1)
** [out :: xxx.xx.xx.xxx]
** [out :: xxx.xx.xx.xxx] Installing tilt (1.3.3)
** [out :: xxx.xx.xx.xxx]
** [out :: xxx.xx.xx.xxx] Installing sprockets (2.1.3)
** [out :: xxx.xx.xx.xxx]
** [out :: xxx.xx.xx.xxx] Installing actionpack (3.2.5)
** [out :: xxx.xx.xx.xxx]
** [out :: xxx.xx.xx.xxx] Installing mime-types (1.19)
** [out :: xxx.xx.xx.xxx]
** [out :: xxx.xx.xx.xxx] Installing polyglot (0.3.3)
** [out :: xxx.xx.xx.xxx]
** [out :: xxx.xx.xx.xxx] Installing treetop (1.4.12)
** [out :: xxx.xx.xx.xxx]
** [out :: xxx.xx.xx.xxx] Installing mail (2.4.4)
** [out :: xxx.xx.xx.xxx]
** [out :: xxx.xx.xx.xxx] Installing actionmailer (3.2.5)
** [out :: xxx.xx.xx.xxx]
** [out :: xxx.xx.xx.xxx] Installing active_record-tableless_model (0.0.1)
** [out :: xxx.xx.xx.xxx]
** [out :: xxx.xx.xx.xxx] Installing arbre (1.0.1)
** [out :: xxx.xx.xx.xxx]
** [out :: xxx.xx.xx.xxx] Installing sass (3.2.4)
** [out :: xxx.xx.xx.xxx]
** [out :: xxx.xx.xx.xxx] Installing thor (0.16.0)
** [out :: xxx.xx.xx.xxx]
** [out :: xxx.xx.xx.xxx] Installing bourbon (3.0.1)
** [out :: xxx.xx.xx.xxx]
** [out :: xxx.xx.xx.xxx] Installing bcrypt-ruby (3.0.1)
** [out :: xxx.xx.xx.xxx]
** [out :: xxx.xx.xx.xxx] Installing orm_adapter (0.4.0)
** [out :: xxx.xx.xx.xxx]
** [out :: xxx.xx.xx.xxx] Installing rack-ssl (1.3.2)
** [out :: xxx.xx.xx.xxx]
** [out :: xxx.xx.xx.xxx] Installing json (1.7.6)
** [out :: xxx.xx.xx.xxx]
** [out :: xxx.xx.xx.xxx] Installing rdoc (3.12)
It started installing gems. What I don't understand is why it did this
during second deploy and not first? My staging and production gems should
be identical. My deploy.rb file has this:
namespace :deploy do
desc Create the gemset
task :create_gemset do
run rvm #{rvm_ruby_string} --create
end
desc Install the bundle
task :bundle do
run bundle install --gemfile #{release_path}/Gemfile --without
development test
end
end
Now the bundle install there should only be installing new gems that are
added. But I didn't add any new gems during this deploy. Any idea why the
capistrano task started installing the above gems?
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[Rails] redis, pub/sub, rails 3, phusion passenger
I have another application publishing messages to redis server. Within my rails application, when a user clicks a button, I want a popup to display that shows live updates. I want the controller to publish notifications to redis, and I want my javascript to subscribe to those events and respond when it finds a suitable channel. What I do not know how to do is actually keep a control open like that: to continuously publish messages when it finds them on redis. Is this possible to do in rails 3/phusion passenger? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/rubyonrails-talk/a1090c0c-8196-4fa7-87e6-3eeaac45bbfe%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
[Rails] find_by_sql query running incredibly slow
Initially, I was using this query: report_ids = [] if units.size 0 units.map(:id).uniq.each do |id| report_id = Report.select(:id).where(unit_id: id).order(time desc).first unless report_id.nil? report_ids report_id end end end reports = Report.where(id: report_ids).order(longitude desc) It looks sloppy, and it took around 7 or 8 seconds to load all the data. So I wanted to create a cleaner, quicker query, so I tried this: reports = Report.find_by_sql([SELECT DISTINCT ON (unit_id) r.* FROM reports r WHERE r.unit_id IN (?) ORDER BY unit_id, time DESC, units.map(:id)]) But this is running incredibly slow. In fact, after 15 minutes, I just cancelled the process. Any idea why the second query is taking markedly longer than the first? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/rubyonrails-talk/cd947975-2605-432d-bdfb-6e25be66e806%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] Optimize query to use sql over ruby iterators
I have the following setup: class Unit has_many :reports end class Report belongs_to :unit end Basically I have a list of units and I want to select the last report for each unit (based on time) and order the resulting last reports by longitude. Sounds simple, but my implementation looks like this: units = current_user.accessible_units report_ids = [] if units.size 0 units.map(:id).uniq.each do |id| report = Report.select(:id).where(unit_id: id).order(time desc).limit(1) if !report.empty? report_ids report.try(:first).try(:id) end end end reports = Report.where(id: report_ids).order(longitude desc) Is there a way to perform this same query using sql (active record relations) and minimize the use of ruby iterators, like map and each? Also notice in query above, I make two hits to the database by querying reports for time and then descending order. Is there a way to eliminate that too? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/rubyonrails-talk/dcd64657-0231-4d6a-ad24-6eab7466a493%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] difference between Self joins and self-referential association
self-joins are discussed here: http://guides.rubyonrails.org/association_basics.html#self-joins self-referential association is discussed here: http://railscasts.com/episodes/163-self-referential-association The main difference I see is that self-referential association creates a join model, such as friendship, which links another model, such as user, to itself, so a user can have many friends (which are other users), and a friend can be befriended by a user. The self-joins looks like there is no join model. Simply a foreign key is added to the same model, such as a manager_id column to the employee model. An employee, who is a manager, can have many other employees, who are subordinates. And the link is done on the same table itself, association the employee manager_id column with the the employee id column. To me, these two techniques look virtually the same. Is there a difference and which is preferred? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/rubyonrails-talk/bdd46a05-4cbe-4db3-ac90-679ffbdfedd5%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] I have bloat. Should I use Rack::Bug, MemoryLogic or Oink on Rails 3 app?
I have severe bloat, spending most of the day killing rack processes on my server. I need to figure out the cause. Most likely too many activerecord objects allocated in memory, to the point that rock process exceeds 1 gig of private dirty memory. Should I use Rack::Bug, MemoryLogic or Oink on Rails 3 app to pinpoint the problem? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/rubyonrails-talk/50c2755f-5068-4590-b71a-3c9d7ddad996%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] rails and passenger memory issues
I'm using Rails 3, Passenger, and Postgresql. Yesterday the rails application was running very slow. So I rebooted the server. Less than 24 hours later, it is consuming even more memory than before and when trying to load the web page, it just hangs forever. I ran passenger-memory-stats to inspect the issue. And once again, I notice 2 rack processes using over 2 gigabytes of private dirty RSS: $ rvmsudo -E /usr/local/rvm/gems/ruby-1.9.3-p327/bin/passenger-memory-stats Use of uninitialized value $includedir in concatenation (.) or string at (eval 9) line 1. Use of uninitialized value $includedir in concatenation (.) or string at (eval 9) line 1. - Apache processes -- PIDPPID VMSizePrivate Name - 1079 1 145.6 MB 0.3 MB /usr/sbin/apache2 -k start 2163 1079 160.5 MB 15.2 MB /usr/sbin/apache2 -k start 2450 1079 145.9 MB 0.5 MB /usr/sbin/apache2 -k start 5638 1079 161.1 MB 15.8 MB /usr/sbin/apache2 -k start 6923 1079 145.8 MB 0.4 MB /usr/sbin/apache2 -k start 9829 1079 160.0 MB 14.9 MB /usr/sbin/apache2 -k start 11016 1079 160.5 MB 15.3 MB /usr/sbin/apache2 -k start 11097 1079 160.5 MB 15.3 MB /usr/sbin/apache2 -k start 11948 1079 145.8 MB 0.4 MB /usr/sbin/apache2 -k start 11961 1079 145.8 MB 0.3 MB /usr/sbin/apache2 -k start 11969 1079 145.8 MB 0.3 MB /usr/sbin/apache2 -k start 12460 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 12461 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 12462 1079 145.7 MB 0.2 MB /usr/sbin/apache2 -k start 12491 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 12533 1079 157.5 MB 14.4 MB /usr/sbin/apache2 -k start 12535 1079 159.8 MB 14.6 MB /usr/sbin/apache2 -k start 12536 1079 157.7 MB 14.3 MB /usr/sbin/apache2 -k start 12552 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 12717 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 12757 1079 150.1 MB 4.6 MB /usr/sbin/apache2 -k start 12990 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 13015 1079 150.3 MB 5.2 MB /usr/sbin/apache2 -k start 13016 1079 159.8 MB 14.4 MB /usr/sbin/apache2 -k start 13045 1079 147.9 MB 4.3 MB /usr/sbin/apache2 -k start 13046 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 13047 1079 152.4 MB 8.9 MB /usr/sbin/apache2 -k start 13288 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 13324 1079 152.4 MB 8.9 MB /usr/sbin/apache2 -k start 13329 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 13331 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 13959 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 13960 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 13961 1079 149.0 MB 3.8 MB /usr/sbin/apache2 -k start 14037 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 14040 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 14051 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 14052 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 14053 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 14059 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 14061 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 14069 1079 148.7 MB 3.4 MB /usr/sbin/apache2 -k start 14089 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 14127 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 14132 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 14149 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 14481 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 14548 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 14552 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 14553 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 14554 1079 146.7 MB 3.4 MB /usr/sbin/apache2 -k start 14555 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 14556 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 14557 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 14593 1079 148.8 MB 3.6 MB /usr/sbin/apache2 -k start 14594 1079 159.8 MB 14.4 MB /usr/sbin/apache2 -k start 14606 1079 146.7 MB 3.4 MB /usr/sbin/apache2 -k start 14792 1079 149.0 MB 3.8 MB /usr/sbin/apache2 -k start 14808 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 14914 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 14915 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 14917 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 14918 1079 145.9 MB 0.3 MB /usr/sbin/apache2 -k start 14920 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 14927 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 14997 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 14998 1079 159.7 MB 14.4 MB /usr/sbin/apache2 -k start 14999 1079 149.0 MB 3.8 MB /usr/sbin/apache2 -k start 15016 1079 145.6 MB 0.2 MB /usr/sbin/apache2 -k start 15239 1079 145.9 MB 0.4 MB /usr/sbin/apache2 -k start 15244 1079 145.9 MB 0.3 MB /usr/sbin/apache2 -k start 15249 1079 145.6 MB 0.2 MB
[Rails] find total months passed between two ActiveSupport::TimeWithZone objects
unit.created_at.class = ActiveSupport::TimeWithZone Time.zone.now.class = ActiveSupport::TimeWithZone Time.zone.now - unit.created_at = 47709736.32316899 I think that's the number of seconds that have passed between when the unit was created and the current time. Is this correct? If so, is there any easier way to find the total months that passed between two time objects like this? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/rubyonrails-talk/ee22138c-7949-4ebb-b1d6-1776362c4f99%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] DateTime now
When using DateTime.now, does the now method return the time based on the remote OS system time or the local time where the user actually invoked the now method, if they are using ssh and running the commands in a rails console, for example? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/rubyonrails-talk/46b3432f-5ab4-42f8-9ac2-1ea8bb30cbb0%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] rails is not to logging controller, action, parameters, complection time, etc in development mode
For this one particular project, rails is not to logging controller, action, parameters, complection time, etc in development mode. And I am not sure why. When I check in the console the log level I notice: Rails.logger.level = 0 So I am not sure why it doesn't log the information it usually does during a request. -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/rubyonrails-talk/ae27ecd7-90a7-44c2-a6bc-c0282e6f3518%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] installing rvm in home directory or system-wide?
Is there any advantages of installing rvm system-wide as opposed to just in the home directory of a user? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/rubyonrails-talk/0a7e0bb6-2e4c-44be-90e6-12099105d787%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] Does each ip request to a ruby on rails application on a server spawn a new ruby process?
When I view the output of the top command on ubuntu, I notice sometimes there is 6 ruby processes. When are each of these processes spawned? http://tinypic.com/view.php?pic=2i24rwhs=5 I cannot imagine that it's every time someone loads the rails application from a different ip address, otherwise I would assume there would be more ruby processes spawned. -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/rubyonrails-talk/594957ab-4038-43c2-883d-640f26599541%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] cap deploy:setup fails
I run cap deploy:setup
And towards the end, I see the following issues:
** [out :: xxx.xx.xx.132] Unrecognized command line flag:
'--autolibs=read-only' ( see: 'rvm usage' )
** [out :: xxx.xx.xx.134] Already installed ruby-1.9.3-p0.
** [out :: xxx.xx.xx.134] To reinstall use:
** [out :: xxx.xx.xx.134]
** [out :: xxx.xx.xx.134] rvm reinstall ruby-1.9.3-p0
** [out :: xxx.xx.xx.134]
** [out :: xxx.xx.xx.132] Ruby ruby-1.9.3-p0 is not installed.
** [out :: xxx.xx.xx.134] gemset created spree_ecommerce =
/usr/local/rvm/gems/ruby-1.9.3-p0@spree_ecommerce
command finished in 931ms
failed: bash -c '__LAST_STATUS=0; export
CURL_HOME=\${TMPDIR:-${HOME}}/.rvm-curl-config.$$\; mkdir ${CURL_HOME}/;
{ [[ -r ${HOME}/.curlrc ]] cat ${HOME}/.curlrc; echo \silent\; echo
\show-error\; } $CURL_HOME/.curlrc; sudo -p '\\''sudo password: '\\''
sg rvm -c \/usr/local/rvm/bin/rvm --autolibs=read-only install
ruby-1.9.3-p0 -j $(cat /proc/cpuinfo 2/dev/null | (grep vendor_id || echo
'\\''vendor_id : Other'\\'';) | wc -l) \; sudo -p '\\''sudo password:
'\\'' sg rvm -c \/usr/local/rvm/bin/rvm ruby-1.9.3-p0 do rvm gemset create
spree_ecommerce\ || __LAST_STATUS=$?; rm -rf $CURL_HOME; exit
${__LAST_STATUS}' on xxx.xx.xx.132
Note that I have another rails application, that deploys fine, whose deploy
configuration is very very similar. Here's the deploy.rb:
require 'capistrano/ext/multistage'
require rvm/capistrano
require 'bundler/capistrano'
after deploy:update_code, deploy:symlink_shared_configs
load 'deploy/assets'
set :application, SpreeSite
set :stages, [staging, production]
set :default_stage, production
set :scm, git
set :repository, g...@github.com:MyAccount/SpreeSite.git
set :branch, master
default_run_options[:pty] = true
role :web, xxx.xx.xx.134 # Your HTTP server,
Apache/etc
role :app, xxx.xx.xx.134 # This may be the
same as your `Web` server
role :db, xxx.xx.xx.132, :primary = true# This is where
Rails migrations will run
set :deploy_to, ~/public_html/mysite.com/
set :user, ubuntuuser
set :use_sudo, false
set :deploy_via, :remote_cache
set :rvm_ruby_string, 'ruby-1.9.3-p0@spree_ecommerce' #this failed on
remote server when using ruby-1.9.3@spree_ecommerce !!
set :rvm_autolibs_flag, read-only
set :rvm_type, :system
set :rvm_install_with_sudo, true
before 'deploy:setup', 'rvm:install_rvm' # install RVM
before 'deploy:setup', 'rvm:install_ruby' # install Ruby and create
gemset, OR:
before 'deploy:setup', 'rvm:create_gemset' # only create gemset
# If you are using Passenger mod_rails uncomment this:
namespace :deploy do
desc Symlink configuration files
task :symlink_shared_configs, :roles = [:db,:app] do
run ln -nfs #{shared_path}/config/database.yml
#{release_path}/config/database.yml
end
task :start do ; end
task :stop do ; end
task :restart, :roles = :app, :except = { :no_release = true } do
run #{try_sudo} touch
#{File.join(current_path,'tmp','restart.txt')}
end
end
#deploy/production.rb:
set :deploy_to, /home/ubuntuuser/public_html/mysite.com/
set :rails_env, 'production'
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[Rails] ruby pack unexpected results
I have two hex values and expect back the value 3007
What pack does is take the array of hexes and formats them into a string
(if ASCII representation, then ASCII character, otherwise the raw hex as
string). Then I take the string of hexes and unpack them, that is, get the
unsigned int representation of those bytes:
[0xBF, 0xB].pack('C*').unpack('I')[0]
So I expect back 3007, but the above produces nil.
This is what I want to achieve:
[0xBF, 0xB].reverse.inject { |s,v| s * 256 + v }
= 3007
But I want to use unpack instead of inject.
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[Rails] uninstall dependencies along with the gem
I installed spree by adding it in gemfile. It was giving me errors, so I went to the github site, and installed spree using gem install spree. But now it looks like i have two sets of gems for the dependencies of spree: spree_api (2.0.3, 0.40.0) spree_auth (0.40.0) spree_backend (2.0.3) spree_cmd (2.0.3) spree_core (2.0.3, 0.40.0) spree_dash (0.40.0) spree_frontend (2.0.3) spree_promo (0.40.0) spree_sample (2.0.3, 0.40.0) How do I uninstall spree and all of the gems that were installed along with it? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/rubyonrails-talk/f9d6b22c-7d2d-4a0d-951f-62904f3d09f4%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] yaml and ip addresses
I was using this code
url = http://#{agent_host}:#{agent_port}/home/create_unit?;
And it worked fine in development but for my config.yml, I was
specifying localhost for agent_host. However in production, agent_host
is an actual ip address and it just wouldn't work. So I had to
explicitly put the ip address in production:
url = http://xxx.xxx.xx.xxx/home/create_unit?;
This is what that config file had:
agent_development:
host: localhost
port: 3001
agent_production:
host: xxx.xxx.xx.xxx
port: 80
agent_staging:
host: xxx.xxx.xx.xxx
port: 80
where the x's are replaced with actual numeric values that represent
ip address.
How does the yaml interpret that ip address? As a decimal value? I'm
not sure why when I substitute it into the string interpolation, that
it doesn't in production.
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[Rails] undefined method `stringify_keys' for #String:0x007fe8a3ba0a48
From my understanding, you can pass a block to the link_to helper, but the following code gives me an error undefined method `stringify_keys' for #String:0x007fe8a3ba0a48. = link_to(One time Payment with Paypal or Credit Card, @order.payment_payment_standard_url(new_order_url(invoice: @invoice), payment_notifications_url, @invoice)) do = image_tag https://www.paypalobjects.com/webstatic/ mktg/logo/AM_mc_vs_dc_ae.jpg -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/rubyonrails-talk/b58db872-c5b1-4bea-b7a6-9ec52f856ff6%40r3g2000yqe.googlegroups.com?hl=en-US. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] relationship of shopping cart and order
Most implementations of shopping carts I have seen is that a user stores line items in a cart, where the line items represent products or subscriptions. So a cart has many products through line items and a product can have many carts through line items. Then a customer makes an order and so you introduce a new model order. The order has information such as customer's name, the payment type, and if you are working with a payment gateway, such as paypal, it will contain paypal tokens and recurring tokens. So the order and the cart are two different models, two different purposes. Cart is a thing that enables a customer to store things in, and a order is the thing that handles payments. So I was watching this railscasts and he updates a purchased_at attribute on the cart itself: http://railscasts.com/episodes/142-paypal-notifications?view=comments But is a cart really purchased, or is it the order that is purchased? If the order contains all payment information, shouldn't the order contain the purchased_at attribute and not the cart? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] You have already activated rake 10.0.4, but your Gemfile requires rake 10.0.3.
I'm careful to create separate gemsets for each project, so when I run bundle install, it only installs gems for that gemset. This way gems dont creep into the wrong projects. Now I just pulled a project from github. I made sure I was in the correct gemset, and then I run bundle install and it works fine. but then when I use rake to create the database rake db:create. I get this error: You have already activated rake 10.0.4, but your Gemfile requires rake 10.0.3. What does it mean you already activated rake 10.0.4? All that should be installed for this gemset is whatever is in Gemfile. -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] staging deploy connected to production database
I'm not sure why but I have both a staging and production deploy using the 'capistrano/ext/multistage' gem. I set staging to the default: set :stages, [staging, production] set :default_stage, staging It deploys correctly to the right path: #deploy/staging.rb set :deploy_to, /home/myuser/public_html/mysite/ But it connects to the production database not staging database in my database.yml file: staging: adapter: mysql2 encoding: utf8 database: staging_database pool: 5 username: username password: password socket: /var/run/mysqld/mysqld.sock host: host production: adapter: mysql2 encoding: utf8 database: production_database pool: 5 username: username password: password socket: /var/run/mysqld/mysqld.sock host: host Why is it linking to the production database and not staging? I don't see where that option is specified during the deploy process. -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] rvm/capistrano
When I ran cap deploy:setup, the following actually installed rvm, ruby and the online_store gemset on my staging server: set :rvm_ruby_string, 'ruby-1.9.3-p0@online_store' set :rvm_autolibs_flag, read-only set :rvm_type, :system set :rvm_install_with_sudo, true before 'deploy:setup', 'rvm:install_rvm' # install RVM before 'deploy:setup', 'rvm:install_ruby' # install Ruby and create gemset, OR: before 'deploy:setup', 'rvm:create_gemset' # only create gemset Now that's what you would expect. However, I already had rvm, ruby installed on my server, and all I wanted installed was the gemset called online_store. So why was this unable to detect that rvm and ruby was already installed? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] capistrano/mod_rails
I was following these instructions for capistrano deployment: https://github.com/capistrano/capistrano/wiki/2.x-From-The-Beginning Under the section Application Layer Initialization, it says: We need to tell Capistrano how to “spin up” (start) our application layer. The precise way this works will vary depending on how you’re running your application layer. If you’re using mod_rails, for instance, it will be very different than if you’re using mongrel. Here, I’ll assume you’re using mongrel. By default, when Capistrano needs to start your application layer, it will try to execute a script called “spin”, in the “script” directory of your application, on each remote server. We’ll need to write that script, and then check it into the source repository. Well I'm using mod_rails/passenger. Do I need to be writing any scripts as it suggests when using mod_rails? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] patch levels and ruby
How do you know which patch level to use for ruby? I have one project that uses ruby-1.9.3-p0. When I cd into another project, it says: ruby-1.9.3-p392 is not installed. So which to use: ruby-1.9.3-p0 or ruby-1.9.3-p392? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/rubyonrails-talk/e795aa06-bf20-482b-9443-1df67fa1a1bb%40googlegroups.com?hl=en-US. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] Re: patch levels and ruby
I'm using capistrano. I added this to the recipe: set :rvm_ruby_string, 'ruby-1.9.3-p0@online_store' # use the same ruby as used locally for deployment set :rvm_autolibs_flag, read-only# more info: rvm help autolibs set :rvm_type, :system set :rvm_install_with_sudo, true before 'deploy:setup', 'rvm:install_rvm' # install RVM before 'deploy:setup', 'rvm:install_ruby' # install Ruby and create gemset, OR: before 'deploy:setup', 'rvm:create_gemset' # only create gemset Thats why patch level p0 is there. If I drop the -p0, will it install the latest rvm with each cap deploy? On May 14, 12:53 pm, Walter Lee Davis wa...@wdstudio.com wrote: On May 14, 2013, at 12:37 PM, John Merlino wrote: How do you know which patch level to use for ruby? I have one project that uses ruby-1.9.3-p0. When I cd into another project, it says: ruby-1.9.3-p392 is not installed. So which to use: ruby-1.9.3-p0 or ruby-1.9.3-p392? Personally, with the rash of security updates we have seen lately, I would always use the latest Ruby you can in your major branch. Make sure your tests pass in the app that runs on v.0, and then update to the latest and run them again. If you're using rvm, that's likely how you got locked into v.0 and v.[whatever] in two different apps. If so, then check to see if you have an .rvmrc file in that folder. (Or local equivalent for some other ruby-switcher.) Walter -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. To view this discussion on the web visithttps://groups.google.com/d/msgid/rubyonrails-talk/e795aa06-bf20-482b For more options, visithttps://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] Re: patch levels and ruby
My /usr/local/rvm/gems looks like this (on ubuntu server): cache ruby-1.9.3-p0@globalruby-1.9.3-p194 ruby-1.9.3-p194@TrackingSystem ruby-1.9.3-p0 ruby-1.9.3-p0@online_store ruby-1.9.3-p194@global ruby-1.9.3-p392@TrackingSystem Is this normal to be using so many patch levels? Obviously I want different gemsets for different projects to manage with bundler. But patch levels? On May 14, 1:06 pm, John Merlino stoici...@aol.com wrote: I'm using capistrano. I added this to the recipe: set :rvm_ruby_string, 'ruby-1.9.3-p0@online_store' # use the same ruby as used locally for deployment set :rvm_autolibs_flag, read-only # more info: rvm help autolibs set :rvm_type, :system set :rvm_install_with_sudo, true before 'deploy:setup', 'rvm:install_rvm' # install RVM before 'deploy:setup', 'rvm:install_ruby' # install Ruby and create gemset, OR: before 'deploy:setup', 'rvm:create_gemset' # only create gemset Thats why patch level p0 is there. If I drop the -p0, will it install the latest rvm with each cap deploy? On May 14, 12:53 pm, Walter Lee Davis wa...@wdstudio.com wrote: On May 14, 2013, at 12:37 PM, John Merlino wrote: How do you know which patch level to use for ruby? I have one project that uses ruby-1.9.3-p0. When I cd into another project, it says: ruby-1.9.3-p392 is not installed. So which to use: ruby-1.9.3-p0 or ruby-1.9.3-p392? Personally, with the rash of security updates we have seen lately, I would always use the latest Ruby you can in your major branch. Make sure your tests pass in the app that runs on v.0, and then update to the latest and run them again. If you're using rvm, that's likely how you got locked into v.0 and v.[whatever] in two different apps. If so, then check to see if you have an .rvmrc file in that folder. (Or local equivalent for some other ruby-switcher.) Walter -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. To view this discussion on the web visithttps://groups.google.com/d/msgid/rubyonrails-talk/e795aa06-bf20-482b For more options, visithttps://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] manual vs automatic bundler deployment with capistrano
I assume this is the most up to date documentation for running bundler install when deploying a rails application with capistrano: http://gembundler.com/v1.3/deploying.html In the documentation, it offers two methods for deploying capistrano with bundler: manual vs automatic. Which is preferred? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] capistrano and scm_username and github
In the capistrano wiki, it contains this line: set :scm_username, “foo”. If you access your source repository with a different user name than you are logged into your local machine with, Capistrano needs to know. Actually the way I access my repository through my app is through ssh keys. The only user name I have with github is the one I use to log into github to view my repositories. So I'm not sure if scm_username is needed and what username does it want. -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] Net::HTTP
I'm looking at the documentation:
http://ruby-doc.org/stdlib-2.0/libdoc/net/http/rdoc/Net/HTTP.html
And I notice two uses of Net::HTTP. Both are using GET requests. But
what's the difference? When to use which?
Net::HTTP.start(uri.host, uri.port) do |http|
request = Net::HTTP::Get.new uri
response = http.request request # Net::HTTPResponse object
end
uri = URI('http://example.com/index.html')
res = Net::HTTP.get_response(uri)
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Re: [Rails] rvm installation script
https://rvm.io/rvm/install Look at the first line: Install RVM with ruby (# for pretty output): $ \curl -#L https://get.rvm.io | bash -s stable --autolibs=3 --ruby But later on on that page it sasy: 1. Download and run the RVM installation script Installing the stable release version: user$ \curl -L https://get.rvm.io | bash -s stable So I assume that the addition of --autolibs=3 --ruby means that it instlals all ruby dependencies for you so you dont have to run: rvm requirements ... # For Ruby / Ruby HEAD (MRI, Rubinius, REE), install the following: ruby: /usr/bin/apt-get install build-essential openssl libreadline6 libreadline6-dev curl git-core zlib1g zlib1g-dev libssl-dev libyaml-dev libsqlite3-dev sqlite3 libxml2-dev libxslt-dev autoconf libc6-dev ncurses-dev automake libtool bison subversion pkg-config and install those manually. Is that correct? On Sunday, May 5, 2013 10:41:01 AM UTC-4, Colin Law wrote: On 5 May 2013 00:30, John Merlino stoi...@aol.com javascript: wrote: Which of these scripts is preferred to install rvm on ubuntu server: curl -#L https://get.rvm.io | bash -s stable --autolibs=4 --ruby I don't think-#L is a good idea, but I assume that is a typo curl -L get.rvm.io | bash -s stable --auto I can't see the documentation for --auto, have you got a link for it? Colin -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msg/rubyonrails-talk/-/6u649LpHdMgJ. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] rvm installation script
Which of these scripts is preferred to install rvm on ubuntu server: curl -#L https://get.rvm.io | bash -s stable --autolibs=4 --ruby curl -L get.rvm.io | bash -s stable --auto -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] where exactly are gems?
when you add a gem to the Gemfile and then run bundle install, where does the command look for the gem? If you had gem 'rails', :git = 'github.com/rails/rails.git, I assume it would update your system .rvm gems directory with the latest github commits. But what is the default repository that bundler looks for gems? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] bundle.lock and production deploy
From my understanding, Gemfile.lock lists all the gems installed for the application along with the specific versions used. This means your app will only use the versions mentioned here and no others, even if updates for those gems are available. When you are deploying your application to staging or production, your application is going on a separate server so you want to make sure all the same versions of the gems are installed there as your local development system, so you should use bundle lock in this situation. So does that mean when you use capistrano to do a production deploy, and you always run bundle install during a deploy, should you run bundle lock before you run bundle install during the deploy process to production to make sure that gems aren't updated in production if they are not updated in development computer? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] mysql on different server than rails application
There's a common problem when you run bundle install and it tries to install the msql2 gem but fails when mysql itself is not installed on the machine. What if you have mysql installed on a different machine (because you don't want your web application which is accessible to the public and your mysql database on the same machine)? In this case, do you still have to install mysql on the web application machine just for the sole purpose of making this error go away? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] running bundle sometimes installs other gems than ones specified in Gemfile
Quick question. Often I add a gem to my Gemfile and then run bundle install and I notice that it installs a bunch of other stuff (in addition to what I wanted): Installing warden (1.2.1) Installing devise (2.2.3) Installing fastercsv (1.5.5) Installing formtastic (2.2.1) Installing has_scope (0.5.1) Installing responders (0.9.3) Installing inherited_resources (1.4.0) Does this mean that the gem I want to install is dependent on the aforementioned gems? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] Re: running bundle sometimes installs other gems than ones specified in Gemfile
So this means I don't need to add devise to my Gemfile now and run a bundle because devise is already isntalled and fully functioning in my app? On Apr 23, 6:17 pm, Scott Ribe scott_r...@elevated-dev.com wrote: On Apr 23, 2013, at 3:52 PM, John Merlino wrote: Does this mean that the gem I want to install is dependent on the aforementioned gems? Yes, one of the features is that it finds and installs dependencies for you, so you only have to list what you know that you're using directly, and not worry about all the requirements to get to where you can use them. -- Scott Ribe scott_r...@elevated-dev.comhttp://www.elevated-dev.com/ (303) 722-0567 voice -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] heruko performance vs shared hosting performance
This guy is using godaddy shared hosting for his wordpress blog. I think it's currently $5 a month. I was thinking to use Rails for his next project. But I wouldn't want costs to exceed more than $20 per month. I contacted heroku and they said that 1 dyno is free to host your ruby on rails app and each additional dyno is $30 a month. A single Heroku dyno provides 512mb ram and 1024mb swap. It has 4 (virtual) CPU cores (Intel Xeon X5550 @ 2.67GHz). 512mb ram doesn't seem to be much, particularly for memory-intensive processing. Although, the multiple CPU cores may enhance multi-threading. That said, this really isn't going to be a memory hog. Now I was curious to compare these specs with that of a shared hosting environment (where many different customers share the same resources). For example, godaddy says this about their shared hosting Currently there is not a ‘set number’ for CPU resources. Mostly because we have multiple hardware platforms in the wild. Simply put, if your processes degrade performance for other customers on the server(s) we will take actions to protect the other customers. So that's not much of a comparison. But does anyone have any experience on shared hosting (I know that most shared hosting environments dont support ruby - but Im sure you used it for other platfroms like asp.net/php) vs heroku, and if someone is used to shared hosting with moderate traffic to their site, would you notice a significant performance downgrade if the site is moved to heroku on 1 dyno? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] heruko performance vs shared hosting performance
This guy is using godaddy shared hosting for his wordpress blog. I think it's currently $5 a month. I was thinking to use Rails for his next project. But I wouldn't want costs to exceed more than $20 per month. I contacted heroku and they said that 1 dyno is free to host your ruby on rails app and each additional dyno is $30 a month. A single Heroku dyno provides 512mb ram and 1024mb swap. It has 4 (virtual) CPU cores (Intel Xeon X5550 @ 2.67GHz). 512mb ram doesn't seem to be much, particularly for memory-intensive processing. Although, the multiple CPU cores may enhance multi-threading. That said, this really isn't going to be a memory hog. Now I was curious to compare these specs with that of a shared hosting environment (where many different customers share the same resources). For example, godaddy says this about their shared hosting Currently there is not a ‘set number’ for CPU resources. Mostly because we have multiple hardware platforms in the wild. Simply put, if your processes degrade performance for other customers on the server(s) we will take actions to protect the other customers. So that's not much of a comparison. But does anyone have any experience on shared hosting (I know that most shared hosting environments dont support ruby - but Im sure you used it for other platfroms like asp.net/php) vs heroku, and if someone is used to shared hosting with moderate traffic to their site, would you notice a significant performance downgrade if the site is moved to heroku on 1 dyno? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] strange behavior with active relation any? method
In console, I run the following and any? returns true:
drivers = Driver.select(drivers.*,
drivers.id).joins([:reports, :driving_habits]).where(extract(MONTH
FROM reports.time) = ? AND extract(YEAR FROM reports.time) = ?, 3,
2013).uniq.order(drivers.id asc).page(2).per(1)
drivers.any?
= true
This correctly evaluates to true because the relation contains one
returned record.
However, I run the same query within the Rails app itself, and any?
must evaluate @drivers in the view to either false or nil, because the
else is triggered instead when I click on second page in view. What's
even weirder is that when I call inspect on @drivers, then
@drivers.any? is evaluated to true in the view when I click on the
second page using kaminari:
@drivers = Driver.select(drivers.*, #{sort_column})
.joins([:reports, :driving_habits])
.by_month(for_selected_month.to_i,
for_selected_year.to_i)
.order(sort_column + + sort_direction)
.page(params[:page]).per(1)
puts The drivers #{@drivers.inspect}
What's driving all this weird behavior?
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[Rails] invoking helper method in controller and view breaks the separation of concern?
I came across some posts which postulate that it's undesirable to
share helper methods across controller and views because UI code
(designed to render HTML) should be separate from controller code
(designed for handling requests). That makes sense but there are
times, a good example is filtering, when it only makes sense to create
a reusable method to query against the params hash from both
controller and view. For example, I created some custom filtering and
sorting. When a http request is initially made, my controller must be
able to query the database for results without user input.
# controller layer (query a default without user input)
helper_method :sort_column, :sort_direction, :for_selected_month,
:for_selected_year
def driver_reports_table
@drivers = Driver.select(drivers.*,
#{sort_column}).joins([:reports,
:driving_habits]).by_month(for_selected_month.to_i,
for_selected_year.to_i).order(sort_column + +
sort_direction).page(params[:page]).per(10)
@unit = current_unit
respond_to do |format|
format.html { render :partial = '/home/reports/
driver_reports_table', :layout = false, :locals = { :drivers =
@drivers, :unit = @unit } }
format.json { render :json = @drivers}
end
end
private
def sort_column
if legal_attributes.include? params[:order]
params[:order]
else
drivers.id
end
end
def sort_direction
%w[asc desc].include?(params[:direction]) ? params[:direction] :
asc
end
def for_selected_month
(params[:date] params[:date][:month]) || Time.now.month
end
def for_selected_year
(params[:date] params[:date][:year]) || Time.now.year
end
def legal_attributes
@columns ||= Driver.column_names + DrivingHabit.column_names
end
In my view layer, the user will interact with form elements and links
to modify the values of the params hash
In one situation, I have a form tag where the user will set the date
and date and month/year attributes of the params hash:
#view
= form_tag driver_reports_path, :method = 'get', :id =
'drivers_filter' do
%fieldset.filter_tab
= select_month(Date.today)
= select_year(Date.today, :start_year = 2012, :end_year =
Time.now.year)
= submit_tag Filter Date
= render '/home/reports/driver_reports_table'
In another situation, I have links where the user will set the sort
and direction attributes of the params hash, depending on which link
they click:
#partial
= hidden_field_tag :sort, params[:sort]
= hidden_field_tag :direction, params[:direction]
...
%table.sortable
%tr
= sortable id, :order = drivers.id
#helper
def sortable(column, query_string={})
title ||= column.titleize
query_string[:order] = query_string[:order] || column
css_class = 'driver_refresh'
css_class (column ==
sort_column.gsub(driving_habits.,).gsub(drivers.,) ? current
#{sort_direction} : )
query_string[:direction] = column ==
sort_column.gsub(driving_habits.,).gsub(drivers.,)
sort_direction == asc ? desc : asc
query_string[:page] = nil
content_tag :th, link_to(title,
driver_reports_path(params.merge(query_string)), {:class =
css_class })
end
Each of the situations compensate for the other. If the user selects
an option from the select tag and thus populates the date attributes,
when they click a link, it will merge the date attributes from the
form with the link attributes that were selected and thus send them
together to the server. Conversely, when the form is submitted,
because of the hidden field tags with the current value of the sort
and direction attributes stored in them, those attributes will be send
with the form attributes.
As you can see, my view helper makes use of the sort_column and
sort_direction methods to check the current values in the params hash
to determine how to render the links. So those methods have importance
both in the controller and view layer. So it would make sense to
define the methods once and reuse them in both layers. So what is
wrong with this technique and how else could it be done so as not to
violate the MVC structure and separation of concerns?
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[Rails] Re: storing values in session variable vs instance variable
instance variables are alive as long as the object instance is alive. My question then would be from one http request to the next does the same controller instance remain alive? If so, then there's no need for sessions at all. Right? On Tuesday, March 19, 2013 12:23:44 PM UTC-4, Ruby-Forum.com User wrote: Norm Scherer wrote in post #1102294: On 03/18/2013 10:37 AM, John Merlino wrote: Is there a good practice when to use the session variable. Sometimes I find myself using both the session variable and instance variable. For example, I have a table that allows a user to select a date. I store the date both in the session and in the instance variable. Should I not bother to store it in session? In what situations should you use the session variable? -- The rails session persists across requests while instance variables do not. If you need something in a following request it (or a reference) must be in the session. If you do not need it later I always use an instance variable. I wouldn't say that this is precisely accurate. You could continue passing a variable from one request to another, and to third, and so on. Session variables are useful when you really need a value to persist for the entire session. I would also say that it's good practice to use session variable sparingly. Session variables are somewhat akin to global variables in the sense that they represent globally accessible shared state (at least within the context of the current session). Session variables are also long lived, taking up memory as long as the session is kept alive. Although in a Rails application sessions are torn down and recreate upon every request, but that might even be worse than just leaving them in memory between requests. Another thing to keep in mind is that by default Rails uses a cookie based session storage mechanism, which means sessions have a hard 4K limit (cookies are limited to 4K by spec). Another reason to avoid putting large amounts of data in the session. A typical use case for session variable are things like the id of the current user. Notice I said the id not the user object itself. It's better to load the user object when, and only when, necessary. There are other great uses for session variables, but think twice about if it's really necessary and try to keep the amount of data as small as possible. Remember for every variable in the session is just one more thing that has to be loaded from persistent storage on every single request. -- Posted via http://www.ruby-forum.com/. -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msg/rubyonrails-talk/-/WjlpqhZwf88J. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] using multiple joins in queries
I have this query:
Report.
joins(:alerts).
joins(:alert_code).
where(:unit_id = unit_id).
where{time my{self.time}}.
where(alert_codes.name LIKE ?, %Inside virtual
fence%).
order(reports.time DESC).first
Basically, it breaks:
ActiveRecord::ConfigurationError (Association named 'alert_code' was
not found; perhaps you misspelled it?):
My associations look like this:
report has_many alerts
alert belongs_to :alert_code, :foreign_key = :code
I am trying to get the first report whose alerts belongs to alert_code
whose name is inside virtual fence. So there are 3 associations
here. Trying to establish the connection.
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[Rails] storing values in session variable vs instance variable
Is there a good practice when to use the session variable. Sometimes I find myself using both the session variable and instance variable. For example, I have a table that allows a user to select a date. I store the date both in the session and in the instance variable. Should I not bother to store it in session? In what situations should you use the session variable? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscr...@googlegroups.com. To post to this group, send email to rubyonrails-talk@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msg/rubyonrails-talk/-/wT4_mu7jFkMJ. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] render and render_to_string
render_to_string returns the result of executing some template or
partial in a string instead of sending it as the response body to the
browser. Render returns the result of evaluating some template or
partial as a string of html, like render_to_string, but it then sends
it back as part of the response body to the browser. Now with ajax,
when I use jquery's get method like this:
$.get(url, function(resp) {
$('#tabs').append(resp);
})
If I use render_to_string, it sends an actual string back the browser
and thats what is appended to the DOM. When I use render, it returns
HTML back to the browser and thats what is correctly appended to the
DOM.
So what causes the difference? Does render send as part of the
response body a header like text/html or something?
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[Rails] check how long individual active record queries take to the database
I know that Rails output log shows how many milliseconds a sql query
take but I'm looking for something more fine-tuned. I want to know how
long individual activerecord queries take on an indiivdual basis. For
example, I have code that looks like this:
items = current_user.accessible_items
@items = items.where{item_id ==
my{current_user.item_id}}.ordered
@other_items = current_user.accessible_items.where{item_id !=
my{current_user.item_id}}.ordered
@accounts = @other_items.accounts.ordered
There are several database hits here. How can I check how long they
take?
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[Rails] Re: evaluating expressions left to right
That was my hunch. Thanks for clarifying. On Wednesday, December 26, 2012 6:48:18 PM UTC-5, Matt Jones wrote: On Tuesday, 25 December 2012 20:13:16 UTC-5, John Merlino wrote: ok, it didn't look like nested methods. But I made to believe that this: sum=square*deviation|a is exactly the same as this: sum=(square*(deviation|(a))) So if this is true, then still a question remains. That's not how it parses, thanks to operator precedence - the same reason that 2+5*10+3 parses as 2.+((5.*(10)).+(3)) and not 2.+(5.*(10.+(3))). You can use a tool like Ripper ( http://www.rubyinside.com/using-ripper-to-see-how-ruby-is-parsing-your-code-5270.html) to see exactly how something is being parsed. Trying your expression yields: [:program, [[:binary, [:vcall, [:@ident, sum, [1, 0]]], :=, [:binary, [:binary, [:vcall, [:@ident, square, [1, 5]]], :*, [:vcall, [:@ident, deviation, [1, 12, :|, [:vcall, [:@ident, a, [1, 22]]] Or, distilled back to a fully-parenthized code version: sum = ((square*deviation) | a) With the method calls written out explicitly: sum.=((square.*(deviation)).|(a)) Essentially, this creates a function that calculates the squared deviation from the mean (square*deviation), applies it to the list a, and then sums the resulting values. This sort of confusion is why most people recommend avoiding operator overloading in most cases - there are a bunch of precedence rules built into the language, and you're essentially stuck with them. --Matt Jones -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msg/rubyonrails-talk/-/Td1UvO4YivgJ. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] Re: evaluating expressions left to right
ok, it didn't look like nested methods. But I made to believe that
this:
sum=square*deviation|a
is exactly the same as this:
sum=(square*(deviation|(a)))
So if this is true, then still a question remains.
Here's the original context again:
module Functional
def compose(f)
if self.respond_to?(:arity) self.arity == 1
lambda { |*args| self[f[*args]] }
else
lambda {|*args| self[*f[*args]] }
end
end
alias * compose
def apply(enum)
enum.map self
end
alias | apply
def reduce(enum)
enum.inject self
end
alias = reduce
end
class Proc
include Functional
end
#client code
a = [1,2,3]
sum = lambda { |x,y| x+y }
mean = (sum=a)/a.size
deviation = lambda { |x| x-mean }
square = lambda { |x| x*x }
standardDeviation = Math.sqrt((sum=square*deviation|a)/(a.size-1))
On the last line, this executes first:
deviation|a
this returns a new array of how far each of elements are from the
mean.
Then this array gets passed to * which is invoked on square (a lambda
object):
square*returned_array
That calls compose where f parameter is the returned array from above.
So then this line is returned by compose since the array object doesnt
respond to arity:
lambda {|*args| self[*f[*args]] }
So it appears the return value of compose is the lambda object. That
presents a problem because = expects an enum argument.
sum=this_should_be_an_enum
On Dec 23, 3:14 am, 7stud -- li...@ruby-forum.com wrote:
In this method call:
meth1(meth2(meth3))
...which value has has to be computed first so that meth1 can return?
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[Rails] passing lambda when expecting an enumerable
Here are two methods defined in the Proc class, designed to be used
for functional programming:
def apply(enum)
enum.map self
end
alias | apply
def reduce(enum)
enum.inject self
end
alias = reduce
Here's an application of them:
sum = lambda {|x,y| x+y }
mean = (sum=a)/a.size
deviation = lambda {|x| x-mean }
square = lambda {|x| x*x }
standardDeviation = Math.sqrt((sum=square|(deviation|a))/(a.size-1))
This excerpt is taken from The Ruby Programming Language.
Here's the thing. In the last line of the above code it uses
sum=square. That reduce method expects an enumerable as an
argument. And instead it is being sent a lambda held in square
variable. This should fail because the inject method does not exist on
the lambda. It exists on arrays, and other enumerable types. So what
am I missing here?
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[Rails] Re: passing lambda when expecting an enumerable
ok I see what it;s doing. Its first calculating this part:
(deviation|a)
to check how far the elements deviate from the mean and returns an
array of the differences.
Then what happens next is that the square| is invoked on the returned
array from above:
square|deviation_returned_array
So it squares the result set, which returns an array of the
deviation_returned_array squared. THen we invoke reduce passing
squared_deviation_returned_array enumerable to the sum proc, which
just totals the result set:
sum=squared_deviation_returned_array
And then divide by (a.size-1) and take the square root of it.
So I guess the lesson here is not only do parentheses indicate
priority in evaluating an expression, but the expressions next to the
ones in parentheses are evaluated before starting to evaluate from
left to right.
On Dec 22, 10:10 am, John Merlino stoici...@aol.com wrote:
Here are two methods defined in the Proc class, designed to be used
for functional programming:
def apply(enum)
enum.map self
end
alias | apply
def reduce(enum)
enum.inject self
end
alias = reduce
Here's an application of them:
sum = lambda {|x,y| x+y }
mean = (sum=a)/a.size
deviation = lambda {|x| x-mean }
square = lambda {|x| x*x }
standardDeviation = Math.sqrt((sum=square|(deviation|a))/(a.size-1))
This excerpt is taken from The Ruby Programming Language.
Here's the thing. In the last line of the above code it uses
sum=square. That reduce method expects an enumerable as an
argument. And instead it is being sent a lambda held in square
variable. This should fail because the inject method does not exist on
the lambda. It exists on arrays, and other enumerable types. So what
am I missing here?
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[Rails] evaluating expressions left to right
class Proc
def apply(enum)
enum.map self
end
alias | apply
def reduce(enum)
enum.inject self
end
alias = reduce
def compose(f)
if self.respond_to?(:arity) self.arity == 1
lambda {|*args| self[f[*args]] }
else
lambda {|*args| self[*f[*args]] }
end
end
alias * compose
end
sum = lambda {|x,y| x+y }# A function to add two numbers
mean = (sum=a)/a.size # Or sum.reduce(a) or a.inject(sum)
deviation = lambda {|x| x-mean } # Function to compute difference from
mean
square = lambda {|x| x*x } # Function to square a number
standardDeviation = Math.sqrt((sum=square*deviation|a)/(a.size-1))
Ok so now I have another example from this book which does not contain
parentheses around deviation|a. So then why is this part:
(sum=square*deviation|a)
not evaluated from left to right.
Apparently, it evaluates this part:
deviation|a
first
and this part second:
square*deviation|a
and then finally:
sum=
So it looks like it is evaluating from right to left. Even though it
should be evaluating from left to right...
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[Rails] reading bytes and blocking
I come across this method: read(n=nil, buffer=nil) – read n bytes (or fewer, if EOF is reached), blocking if necessary, until the bytes are ready. What does it mean blocking if necessary? Blocking what? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] why is thread asleep?
In this example:
1.9.3p0 :001 def threading
1.9.3p0 :002? i = 0
1.9.3p0 :003? while i = 50
1.9.3p0 :004? sleep(2)
1.9.3p0 :005? i += 1
1.9.3p0 :006? if i == 50
1.9.3p0 :007? puts the thread is finished at #{Time.now}
1.9.3p0 :008? end
1.9.3p0 :009? end
1.9.3p0 :010? end
= nil
1.9.3p0 :011 t = Thread.new { threading }
= #Thread:0x007f833d301660 sleep
1.9.3p0 :012 t.status
= sleep
1.9.3p0 :013 t.stop?
= true
1.9.3p0 :014 t.alive?
= true
#few minutes later:
1.9.3p0 :015 the thread is finished at 2012-10-25 21:52:43 -0400
As soon as threading is invoked in the new thread, I check its status.
And the status is sleep. Why is it sleep and not runnable?
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[Rails] Re: why is thread asleep?
Oh I see, because of the call to Kernel.sleep forces the thread in a
sleeping state.
On Oct 25, 9:55 pm, John Merlino stoici...@aol.com wrote:
In this example:
1.9.3p0 :001 def threading
1.9.3p0 :002? i = 0
1.9.3p0 :003? while i = 50
1.9.3p0 :004? sleep(2)
1.9.3p0 :005? i += 1
1.9.3p0 :006? if i == 50
1.9.3p0 :007? puts the thread is finished at #{Time.now}
1.9.3p0 :008? end
1.9.3p0 :009? end
1.9.3p0 :010? end
= nil
1.9.3p0 :011 t = Thread.new { threading }
= #Thread:0x007f833d301660 sleep
1.9.3p0 :012 t.status
= sleep
1.9.3p0 :013 t.stop?
= true
1.9.3p0 :014 t.alive?
= true
#few minutes later:
1.9.3p0 :015 the thread is finished at 2012-10-25 21:52:43 -0400
As soon as threading is invoked in the new thread, I check its status.
And the status is sleep. Why is it sleep and not runnable?
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[Rails] limitations of passing a block to class_eval
One shortcoming of define_method is that it does not allow you to
specify a method body that expects a block. If you need to dynamically
create a method that accepts a block, you will need to use the def
statement within class_eval. Here's a trivial example:
class Module
def acts_as_thing(name, block)
self.class_eval {
define_method(name, block)
}
end
end
class Thing
#using define_method does not allow us to specify a method body that
expects a block, because the block used in define method becomes the
method body itself, not a block passed to a method body.
acts_as_thing :animals do
puts animal group
end
def initialize(name)
@name = name
end
end
#To address the limitations of define_method, that is, to dynamically
create a method that accepts a block, we need to use the def statement
with class_eval.
Thing.class_eval {
def spell_out_name
yield @name
end
}
thing = Thing.new(dog)
thing.animals # = animal group
thing.spell_out_name {|name| puts The name is #{name}.} # = The
name is dog.
Here's my question. I am reading a book called The Ruby Programming
Language. It says the following:
If the method you are creating is sufficiently dynamic, you may not
be able to pass a block to class_eval and will instead have to specify
the method definition as a string to be evaluated.
I'm not sure what they are talking about here. What does it mean by
sufficiently dynamic? In my example above, I proved that a method
defined within the context of class_eval can accept a block.
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[Rails] Why does Kernel define class_eval?
First, I'd like to say it makes sense to define instance_eval in
BasicObject. Both object instances (e.g. obj = Object.new or obj =
MyClass.new) and class objects (e.g. MyClass = Class.new) are both
instances of a class, in the former of the class Object or a client-
defined class (which implicitly inherits from Object) and in the
latter of the class Class. But because they are both instances, we
want to give them both access to the method instance_eval. It makes
sense to define this method instance_eval in either Object or
BasicObject, so that they will be inherited by regular object
instances and class objects.
class_eval is justifiably declared in the Module class. class_eval
evaluates a class and adds instance methods to that class. All class
objects are instances of Class, and Module is the superclass of Class.
Hence, all class objects have access to the instance methods of
Module, where class_eval is defined, in addition to them having access
to the instance methods of class Class. For example:
1.9.3p0 :092 MyClass.class_eval {
1.9.3p0 :093 def my_class
1.9.3p0 :094? puts yes im an instance method of
#{self.class.name}
1.9.3p0 :095? end
1.9.3p0 :096? }
= nil
1.9.3p0 :097 MyClass.new.my_class
yes im an instance method of MyClass
Basically, what we did with class_eval is evaluate the class context
to add methods to it for the class' instances. So it really would not
make sense to have a class_eval definition available to instances
themselves. Yet, in the current library, it's possible:
1.9.3p0 :098 obj = Object.new
= #Object:0x007ff4ec8fc0f8
1.9.3p0 :099 obj.class_eval {}
= nil
What's written above really doesn't make any sense, but it works.
There's no NoMethodError exception raised when invoking class_eval on
the object instance. In actuality, that class_eval invocation does not
trace to Module's definition of class_eval. That would be impossible,
because obj is an instance of Object class, which inherits from
BasicObject and the inheritance chain stops there. There's no Module
in obj's inheritance chain. So then where is class_eval defined for
obj? It's defined in Kernel:
1.9.3p0 :083 Kernel.instance_methods(false).include? :class_eval
= true
As you may know, the Kernel module is included in Object and hence all
its method definitions become available as instance methods to Object,
so that when our obj instance invokes class_eval, it will first search
Object class, and then check the module Kernel, where the definition
will be found.
But I don't see why class_eval is defined in Object. The obj instance
is not a class object, and therefore the new method is not available
to it, so it's not like we can add instance methods to obj within the
block of class_eval:
1.9.3p0 :098 obj = Object.new
= #Object:0x007ff4ec8fc0f8
1.9.3p0 :101 obj.class_eval {
1.9.3p0 :102 def my_class
1.9.3p0 :103? puts yes im an instance method of
#{self.class.name}
1.9.3p0 :104? end
1.9.3p0 :105? }
= nil
1.9.3p0 :106 obj.new.my_class
NoMethodError: undefined method `new' for #Object:0x007ff4ec8fc0f8
#as expected, the exception is raised, because obj is not a class
object.
So why is class_eval in Kernel? obj is not a class object, and we
shouldn't be allowed to invoke class_eval on obj...
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[Rails] What is the best way to check if a method is a singleton method or an instance method?
Let's say I want to check if a method of an object is an instance method or a singleton method, what is the best way to do it? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] IRB vs ruby-doc.org
The ruby documentation says instance_variable_set is a public instance method of Object: http://ruby-doc.org/core-1.9.3/Object.html#method-i-instance_variable_set And I believe it because you can call it on instances of Object: 1.9.3p0 :005 Object.new.instance_variable_set :@a, 1 = 1 It can't be a public instance method of Class or Module, because otherwise the Object instance wouldnt have access to it, since the above Object instance is an instance of Object, whose superclass is BasicObject and that's it. So my question is why when I launch IRB in Rails 3/Ruby 1.9.3, and return as an array the instance methods of Object, instance_variable_set is no where to be found: 1.9.3p0 :001 Object.instance_methods(false) = [:psych_to_yaml, :to_yaml_properties, :to_yaml, :in?, :blank?, :present?, :presence, :acts_like?, :try, :html_safe?, :duplicable?, :to_param, :to_query, :`, :instance_values, :instance_variable_names, :to_json, :with_options, :as_json] Shouldn't instance_variable_set be listed here? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] marshal vs yaml
I notice how Rails makes heavy use of YAML serialization, but a lot of the Ruby literature I come across places emphasis on Marshal. One powerful technique with marshal is the marshal_dump and marshal_load hooks used to customize storing and retrieving object states. For example, let's say I have an object that can store as instance variables an arbitrary array of integers. And let's say I simply want to marshal that array rather than the whole object state, and then later retrieve that data and store it into an allocated but unitialized new instance of the object. Then the marshal_dump and marshal_load hooks come in handy: class Point def initialize(*coords) @coords = coords end def marshal_dump @coords.pack(w*) end def marshal_load(s) @coords = s.unpack(w*) end end Is there a more effective way to achieve something like this in YAML that the Rails community prefers? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msg/rubyonrails-talk/-/GZdvmxERMyYJ. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] dup/clone and taintedness
I was reading this: these methods allocate a new instance of the class of the object on which they are invoked. They then copy all the instance variables and the taintedness of the receiver object to the newly allocated object. What does it mean taintedness? thanks for response -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] TypeError: can't make subclass of Class
Why can't a class be an instance of class Class and also inherit from class Class in ruby? Let's say I defined a singleton method on Class: 1.9.3p0 :032 class Class 1.9.3p0 :033? def Class.class_singleton 1.9.3p0 :034? puts 'class singleton' 1.9.3p0 :035? end 1.9.3p0 :036? end And I want to create a class that can inherit that singleton method: 1.9.3p0 :039 class Q Class 1.9.3p0 :040? end TypeError: can't make subclass of Class How then could it be possible to access that singleton method without directly calling it on Class? And why is inheriting from Class not allowed? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] more misleading content on the web regarding ruby method lookup algorithm
I read this article: http://www.madebydna.com/all/code/2011/06/24/eigenclasses-demystified.html Author makes claim that are flat out wrong. She says: Class gets pushed up the lookup chain and becomes a superclass. That statement is flat out wrong. A class object does not inherit from class Class. In fact, if you try it you will get a TypeError. A class object is an instance of class Class. If a class object does not inherit from anything, then it implicitly inherits from class Object, which itself is an instance of class Class. What happens is as follows: First off, when a class (aka singleton) method is defined on class Dog, an eigenclass is created. For all intents and purposes, this eigenclass becomes the class of the Dog object. Class does not get pushed up the lookup chain. It's the superclass that gets pushed up the lookup chain, which in this example, is Mammal. In other words, it will look at Dog's eigenclass and if it doesn't find it there, it will then look at Mammal's eigenclass, and then Object (so its Object that continuously gets pushed back) and then BasicObject. Here's an example that shows Class does not get pushed back, because the class object never even inherits the eigenclass of Class to begin with (the class object is simply an instance of Class): Loading development environment (Rails 3.1.2) 1.9.3p0 :001 class Mammal 1.9.3p0 :002? def Mammal.mammal_singleton 1.9.3p0 :003? puts 'mammal singleton' 1.9.3p0 :004? end 1.9.3p0 :005? end = nil 1.9.3p0 :006 1.9.3p0 :007class Dog Mammal 1.9.3p0 :008? def Dog.dog_singleton 1.9.3p0 :009? puts 'dog singleton' 1.9.3p0 :010? end 1.9.3p0 :011? end = nil 1.9.3p0 :012 1.9.3p0 :013class Object 1.9.3p0 :014? def Object.object_singleton 1.9.3p0 :015? puts 'object singleton' 1.9.3p0 :016? end 1.9.3p0 :017? end = nil 1.9.3p0 :018 1.9.3p0 :019class Class 1.9.3p0 :020? def Class.class_singleton 1.9.3p0 :021? puts 'class singleton' 1.9.3p0 :022? end 1.9.3p0 :023? end = nil 1.9.3p0 :024 Dog.dog_singleton dog singleton = nil 1.9.3p0 :025 Dog.mammal_singleton mammal singleton = nil 1.9.3p0 :026 Dog.object_singleton object singleton = nil 1.9.3p0 :027 Dog.class_singleton NoMethodError: undefined method `class_singleton' for Dog:Class from (irb):27 #It fails because class Class is not in the eigenclass lookup chain of Dog class object, since class Class is not a superclass of Dog. However, by defining an instance method in class Class, then that will be able to be invoked on Dog, since Dog is an instance of class Class: 1.9.3p0 :028 class Class 1.9.3p0 :029? def class_instance 1.9.3p0 :030? puts 'class instance' 1.9.3p0 :031? end 1.9.3p0 :032? end = nil 1.9.3p0 :033 Dog.class_instance class instance = nil So the real question is this, which that article obscured. If I invoke a method on Dog, will it search the Class hierarchy for an associated instance method first (and continue looking up the lookup algorithm for instance methods via Module, Object, and BasicObject which class Class inherits from) or will it search Dog's eigenclass and its superclasses' eigenclasses (all the way up to the eigenclass of Object and BasicObject) first? The proof is in the pudding: 1.9.3p0 :044 class Object 1.9.3p0 :045? def Object.sing_method 1.9.3p0 :046? puts 'singleton method' 1.9.3p0 :047? end 1.9.3p0 :048? def inst_method 1.9.3p0 :049? puts 'instance method' 1.9.3p0 :050? end 1.9.3p0 :051? end = nil 1.9.3p0 :052 Dog.sing_method singleton method = nil 1.9.3p0 :053 Dog.inst_method instance method = nil #as suspected, invocations on Dog lead to both eigenclass methods of Object and instance methods of Object, since Dog is an instance of class Class, and class Class inherits from Object via Module, and Dog at the same time inherits from Object (via inheritance), which is done implicitly by Ruby. Now which get invoked first, the instance methods or eigenclass methods? 1.9.3p0 :062 class Object 1.9.3p0 :063? def Object.method_lookup 1.9.3p0 :064? puts 'eigenclass method called first!' 1.9.3p0 :065? end 1.9.3p0 :066? def method_lookup 1.9.3p0 :067? puts 'instance method is called first!' 1.9.3p0 :068? end 1.9.3p0 :069? end = nil 1.9.3p0 :070 Dog.method_lookup eigenclass method called first! = nil And there you have it, the method resolution algorithm looks up the singleton methods prior to the instance methods of a class object. -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] protected method access
I just want to make a note of something I read here:
http://en.wikibooks.org/wiki/Ruby_Programming/Syntax/Classes#Protected
def =(other)
self.age = other.age
end
It says:
If age is private, this method will not work, because other.age is
not accessible. If age is protected, this will work fine, because
self and other are of same class, and can access each other's
protected methods.
That statement is not actually true. They won't access each other's
protected methods. They will access their own protected methods of the
same class.
Demonstration:
1.9.3p0 :001 class A
1.9.3p0 :002? protected
1.9.3p0 :003? def method
1.9.3p0 :004? puts self is #{self.object_id}
1.9.3p0 :005? end
1.9.3p0 :006? end
1.9.3p0 :009 class A
1.9.3p0 :010? def calling_method(o)
1.9.3p0 :011? self.method
1.9.3p0 :012? o.method
1.9.3p0 :013? end
1.9.3p0 :014? end
= nil
1.9.3p0 :015 b = A.new
= #A:0x007fcfe5b20900
1.9.3p0 :016 a.calling_method(b)
self is 70265443297880
self is 70265444304000
As you can see, b is not invoking a's protected method. It's invoking
its own, that was stored separately in this object, just as the
instance vars are stored separately per object. I'm sure that's what
the book intended, but when it comes to writing, you have to be
careful to clarify for accuracy.
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[Rails] Re: Class, Module, Object
, :pretty_print_cycle, :pretty_print, :xyz] 1.9.3p0 :099 Object.included_modules = [PP::ObjectMixin, ActiveSupport::Dependencies::Loadable, JSON::Ext::Generator::GeneratorMethods::Object, Kernel] And there you go, it worked. On Sep 22, 8:09 pm, Ignacio Piantanida ijpiantan...@gmail.com wrote: Class, Module and Object are instances of the Class class. Class.class = Class Module.class = Class Object.class = Class Class inherits from Module, which inherits from Object Class.superclass = Module Module.superclass = Object So, every instance of the Class class is_a?(Class) and is_a?(Module) and is_a?(Object). 2012/9/22 John Merlino stoici...@aol.com reload! Reloading... = true puts Class Module true = nil puts Module Class false = nil puts Module Object true = nil puts Object Module false = nil Object.parent = Object The above indicates that the Class object instance inherits from the Module object instance and the Module object instance inherits from Object. And Object doesn't inherit from anything. So why do these return true: Module.is_a?(Class) = true Object.is_a?(Module) = true -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visithttps://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] Re: Class, Module, Object
I want to fix a typo. I said: Since Object, Class, and Module are instances of Class class, they don't have access to Class's singleton methods, but rather they have access to Class's instance methods: I meant to say: Object and Module do not inherit from Class and so they don't have access to Class's singleton methods, but since Object, Class, and Module are instances of Class class, they all have access to Class's instance methods: On Oct 3, 11:08 pm, John Merlino stoici...@aol.com wrote: Yes, Object, Class, and Module are more than just constants. Object, Class, and Module are instances of Class class: 1.9.3p0 :031 Class.class = Class 1.9.3p0 :032 Module.class = Class 1.9.3p0 :033 Object.class = Class Since Object, Class, and Module are instances of Class class, they don't have access to Class's singleton methods, but rather they have access to Class's instance methods: 1.9.3p0 :052 class Class 1.9.3p0 :053? def Class.abc 1.9.3p0 :054? puts 'abc' 1.9.3p0 :055? end 1.9.3p0 :056? end = nil 1.9.3p0 :076 Module.abc NoMethodError: undefined method `abc' for Module:Class 1.9.3p0 :077 Object.abc NoMethodError: undefined method `abc' for Object:Class However, since we defined the singleton method on Class, it will work on a Class invocation: 1.9.3p0 :078 Class.abc abc = nil But instance methods work: 1.9.3p0 :012 Class.instance_methods(false) = [:allocate, :new, :superclass, :cattr_reader, :cattr_writer, :cattr_accessor, …] 1.9.3p0 :015 Object.cattr_writer = [] 1.9.3p0 :017 Module.cattr_reader = [] 1.9.3p0 :018 Class.cattr_writer = [] This here is an indication that Object and Module are instances of Class but DO NOT inherit from Class. Let's check that out with the superclass call: 1.9.3p0 :079 Class.superclass = Module 1.9.3p0 :080 Module.superclass = Object 1.9.3p0 :081 Object.superclass = BasicObject 1.9.3p0 :082 BasicObect.superclass = nil Thus, Class inherits from Module, and Module in turn inherits from Object, which in turn inherits from BasicObject in ruby 1.9. We can test that out by seeing if we define a singleton method on Module, then Class should be able to invoke it, since there is inheritance between them. 1.9.3p0 :067 class Module 1.9.3p0 :068? def Module.qqqw 1.9.3p0 :069? puts 'qqqw' 1.9.3p0 :070? end 1.9.3p0 :071? end = nil 1.9.3p0 :072 Module.singleton_methods(false) = [:nesting, :constants, :attr_internal_naming_format, :attr_internal_naming_format=, :qqqw] 1.9.3p0 :073 Class.qqqw qqqw = nil 1.9.3p0 :074 Object.qqqw NoMethodError: undefined method `qqqw' for Object:Class 1.9.3p0 :084 class Object 1.9.3p0 :085? def Object.ttyy 1.9.3p0 :086? puts 'ttyy' 1.9.3p0 :087? end 1.9.3p0 :088? end = nil 1.9.3p0 :089 Module.ttyy ttyy = nil 1.9.3p0 :090 Class.ttyy ttyy = nil This shows the role of inheritance. We defined a singleton method on Object, and thus since Module inherits from Object, it had access to it, and so did Class, since Class inherits from Module, which in turn inherits from Object. Now that's the metaclass (eigenclass) inheritance relationship (the fact that the eighenclass of Class inherits the singleton methods of the eighenclass of Module which in turn inherits the singleton methods of eigenclass of Object). If the inheritance relationship did not exist as it does, then we wouldnt be able to call singleton methods of Module on Class, for example. Furthermore, we have a circular relationship. Since Class is an instance of Class, Module is an instance of Class, and Object is an instance of Class, they all have access to instance methods of Class, as already stated. What's more interesting is the circular relationship that has been created via the combination of instantiation and inheritance. If Object is an instance of Class, and Class inherits from Module, then that means Class is an instance of Module, and so since Object is an instance of Class, it itself is an instance of Module. Hence, we can access the INSTANCE METHODS of any of these classes via the other Class. 1.9.3p0 :094 Class.is_a?(Module) = true 1.9.3p0 :095 Module.is_a?(Class) = true 1.9.3p0 :096 Object.is_a?(Module) = true 1.9.3p0 :097 Object.is_a?(Class) = true Now lets access an instance method of Module on Object: 1.9.3p0 :098 Module.instance_methods(false) = [:freeze, :===, :==, :=, :, :=, :, :=, :to_s, :included_modules, :include?, :name, :ancestors, :instance_methods, :public_instance_methods, :protected_instance_methods, :private_instance_methods, :constants, :const_get, :const_set, :const_defined?, :class_variables, :remove_class_variable, :class_variable_get, :class_variable_set, :class_variable_defined?, :public_constant, :private_constant, :module_exec, :class_exec, :module_eval, :class_eval, :method_defined?, :public_method_defined?, :private_method_defined
[Rails] Re: global methods under object supposedly unaccessible
A private method is internal to the implementation of a class, and it can only be called by other instance methods of the class (or its subclasses). Private methods are implicitly invoked on self, and may not be explicitly invoked on an object. If m is a private method, then you must ibnvoke it in functional style as m. But look at this: 1.9.3p0 :032 class Object 1.9.3p0 :033? def apple2 1.9.3p0 :034? puts 'apple2' 1.9.3p0 :035? end 1.9.3p0 :036? end = nil 1.9.3p0 :037 self.apple2 apple2 = nil Or this: 1.9.3p0 :038 def apple2 1.9.3p0 :039? puts 'apple2' 1.9.3p0 :040? end = nil 1.9.3p0 :041 self.apple2 apple2 = nil I invoked apple2 on self (an explicit receiver). However, according to documentation, defining apple2 in Object should have made it private. Only this would work: 1.9.3p0 :025 class Object 1.9.3p0 :026? private 1.9.3p0 :027? def apple1 1.9.3p0 :028? puts 'apple1' 1.9.3p0 :029? end 1.9.3p0 :030? end = nil 1.9.3p0 :031 self.apple1 NoMethodError: private method `apple1' called for main:Object However, in the above example, I was forced to use the private method. The documentation says any global methods declared outside of a class definition - those methods are defined as private instance methods of Object. In my first examples, I defined a method outside of class definition. But was still able to invoke it on self (self being Object in that case). On Sep 23, 7:16 pm, 7stud -- li...@ruby-forum.com wrote: 1) Post the definition ofprivate. 2) Execute this program: puts 'hello' 3) What conclusions do you draw from that? -- Posted viahttp://www.ruby-forum.com/. -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] struct square brackets method used to instantiate?
I know that Struct class defines the [] instance method: 1.9.3p0 :014 Struct.instance_methods(false) = [:==, :eql?, :hash, :inspect, :to_s, :to_a, :values, :size, :length, :each, :each_pair, : [], : []=, :select, :values_at, :members, :pretty_print, :pretty_print_cycle, :as_json] This allows you to mimic hash behavior via Struct: 1.9.3p0 :016 HashLike = Struct.new(:x,:y) = HashLike 1.9.3p0 :017 h = HashLike.new(1,2) = #struct HashLike x=1, y=2 1.9.3p0 :018 h[:x] = 1 1.9.3p0 :019 h[:y] = 100 = 100 But I come across a use case where the square brackets method was used as instantiation: 1.9.3p0 :001 Point = Struct.new :x, :y do 1.9.3p0 :002 def distance(point) 1.9.3p0 :003? Math.sqrt((point.x - self.x) ** 2 + 1.9.3p0 :004 (point.y - self.y) ** 2) 1.9.3p0 :005? end 1.9.3p0 :006? end = Point 1.9.3p0 :007 Point[3,4].distance Point[0,0] = 5.0 That confuses me. How can [] be used both as both hash key accessors and also instantiation (e.g. new)? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] Re: in Rails, what is the main (global) scope called?
Top-level methods or constants defined outside of any class or module are implicitly defined in Object. On Sep 21, 1:30 pm, John Merlino stoici...@aol.com wrote: For example, you see filescalled rails/actionpack/lib/action_controller/base.rb which adds methods and such to the open module ActionController. Whatscopeis ActionController in? Is it justcalledtheglobalscope? Obviously, there is namespace resolution lookup. And a good example of this is in the Base class of the same file. It references one module like this: AbstractController::Layouts and another module like this: Rendering. One uses the :: namespace resolution operator, because Layouts module is not within thescopethat class Base is, which is module ActionControllerscope, so it has to reference AbstractController which must be in theGLOBALscopein order for ruby to find it and then it can look there to find Layouts. In contrast, Rendering is defined within the ActionControllerscope, and since class Base is defined within the ActionControllerscopeas well, it doesn't need to use the :: operator. It can simply search within thatscopeand find the module Rendering. So what is thatglobalscopethat ActionController and AbstractController are in withinRails? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] How is the Kernel module an ancestor of Object?
inheritance chain: Class - Module - Object Kernel.is_a?(Module) # = true Kernel is an instance of Module, which in turn inherits from Object. So how is Kernel an ancestor of Object? I found it on line 262 of The Ruby Programming Language: The Kernel module is an ancestor of Object. -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] method name resolution
For the method invocation expression o.m, Ruby performs name resolution with the following steps: 1) first, it checks the eigenclass of o for singleton methods named m. 2) If no method m is found in the eigenclass, Ruby searches the class of the o for an instance method named m. 3) If no method m is found in the class, Ruby searches the instance methods of any modules included by the class of o. If that class includes more than one module, then they are searched in the reveerse of the order in which they wre included. That is, the most recently included module is searched first. If no instance method m is found in the class of o or in its modules, then the search moves up the inheirtance hierarchy to the superclass. Steps 2 and 3 are repeated for each class in the inheritance heirarchy until each ancestor class and its included modules have been searched. If no method named m is found after completing the search, then a method named method_missing is invoked instead. In order to find an appropriate definition of this method, the name resolution algorithm starts over at step 1. The kernel module provides a default implementation of method_missing, so this second pass of name resolution is guaranteed to succeed. Notice the part Steps 2 and 3 are repeated for each class in the inheritance heirarchy... What if the superclass has an eigenclass method? Why doesn't it repeat Step 1? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] Re: method name resolution
The answer is that when Ruby searches for singleton methods in the eigenclass of an object, it also searches the superclass (and all ancestors) of the eigenclass as well. On Sep 25, 11:05 pm, John Merlino stoici...@aol.com wrote: For the method invocation expression o.m, Ruby performs name resolution with the following steps: 1) first, it checks the eigenclass of o for singleton methods named m. 2) If no method m is found in the eigenclass, Ruby searches the class of the o for an instance method named m. 3) If no method m is found in the class, Ruby searches the instance methods of any modules included by the class of o. If that class includes more than one module, then they are searched in the reveerse of the order in which they wre included. That is, the most recently included module is searched first. If no instance method m is found in the class of o or in its modules, then the search moves up the inheirtance hierarchy to the superclass. Steps 2 and 3 are repeated for each class in the inheritance heirarchy until each ancestor class and its included modules have been searched. If no method named m is found after completing the search, then a method named method_missing is invoked instead. In order to find an appropriate definition of this method, the name resolution algorithm starts over at step 1. The kernel module provides a default implementation of method_missing, so this second pass of name resolution is guaranteed to succeed. Notice the part Steps 2 and 3 are repeated for each class in the inheritance heirarchy... What if the superclass has an eigenclass method? Why doesn't it repeat Step 1? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] global methods under object supposedly unaccessible
documentation: By default, all methods in Ruby classes are public - accessible by anyone. There are, nonetheless, only two exceptions for this rule: the global methods defined under the Object class, and the initialize method for any class. Both of them are implicitly private. class Object def something puts something end end = nil class XYZ end = nil xyz = XYZ.new = #XYZ:0x10d067580 xyz.something something So then why was I able to access something? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] Class, Module, Object
reload! Reloading... = true puts Class Module true = nil puts Module Class false = nil puts Module Object true = nil puts Object Module false = nil Object.parent = Object The above indicates that the Class object instance inherits from the Module object instance and the Module object instance inherits from Object. And Object doesn't inherit from anything. So why do these return true: Module.is_a?(Class) = true Object.is_a?(Module) = true -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] in Rails, what is the main (global) scope called?
For example, you see files called rails/actionpack/lib/action_controller/base.rb which adds methods and such to the open module ActionController. What scope is ActionController in? Is it just called the global scope? Obviously, there is namespace resolution lookup. And a good example of this is in the Base class of the same file. It references one module like this: AbstractController::Layouts and another module like this: Rendering. One uses the :: namespace resolution operator, because Layouts module is not within the scope that class Base is, which is module ActionController scope, so it has to reference AbstractController which must be in the GLOBAL scope in order for ruby to find it and then it can look there to find Layouts. In contrast, Rendering is defined within the ActionController scope, and since class Base is defined within the ActionController scope as well, it doesn't need to use the :: operator. It can simply search within that scope and find the module Rendering. So what is that global scope that ActionController and AbstractController are in within Rails? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] Re: append_features(mod)
1.9.3p0 :003 class A 1.9.3p0 :004? end 1.9.3p0 :009 A.is_a?(Module) = true 1.9.3p0 :010 A.is_a?(Class) = true 1.9.3p0 :011 Class.is_a?(Module) = true class is module, so answer is append_features is run On Sep 20, 1:23 am, John Merlino stoici...@aol.com wrote: append_features(mod) The documentation says: When this module is included in another, Ruby calls append_features in this module, passing it the receiving module in mod. Ruby’s default implementation is to add the constants, methods, and module variables of this module to mod if this module has not already been added to mod or one of its ancestors. See also Module#include. What if this module is included in a class, will append_features of this module still be called, passing in the class as mod? This is in particular reference to ActiveRecord::Concern, which has its own implementation of append_features overriding ruby's. -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] Re: append_features(mod)
So that explains a lot. When module B is included in class C, we extend ActiveSupport::Concern, which invokes the extended hook in the module Concern, passing module B as local variable base. We want to indicate that module B is a concern, so we set an instance variable @_dependencies on it set to an empty array. Next, since B is included in class C, the included hook in module B is called. The included hook of ruby is overwritten by the included hook of ActiveSupport::Concern. It checks if base was passed as the first argument to the included hook, if not, the block passed to the included hook in module B (which was included in class C) is set to the @_included_block instance variable of Concern. Finally, since a class is an instance of Module, a class is a module. Hence, since we included module B in class C (which itself is a Module), the append_features hook is executed. What append_features does is that when this module is included in another, Ruby calls append_features in this module, passing it the receiving module in mod. ActiveSupport::Concern captures the append_features call and implements its own definition. The class C is passed as base to append_features when module B is included in class C, and we check if class C has the @_dependencies instance variable defined. Since we did not extend ActiveSpport::Concern in class C, it does not have that instance variable set, so the else clause is, in effect, triggered. What we then do is iterate through each of the modules stored in @_dependencies and include them in class C (base). We can have multiple modules in the @_dependencies instance variable, and we have them all included in base here, so that if one depends on another, they are all available now in class C. It then extends ClassMethods and includes InstanceMethods if they are defined in module B. It finally invokes class_eval method on base (class C), passing in the instance variable @_included_block if it is defined. @_included_block stores the block that we passed into included call in module B, if we did not pass an argument (other than the block) to the included call. So that block gets evaluated in the class context of C, and hence we can call class methods within that block. Next notice that module A is included in module B. Ruby now evaluates module A. The extended method is called, and it points to ActiveSupport::Concern again. So the extended hook of Concern is invoked, we pass module A as local variable base, and we set the @_dependencies instance variable to an empty array. However, there is no included hook in module A, so that is skipped. Ruby then invokes append_features, since module A was included in module B. appended_features gets passed the receiving module (module B) in module A context. We check if module B has the @_dependencies instance method defined. It does actually (since remember in module B we extended ActiveSupport::Concern which we did not do in class A). So since module B has that instance variable set, we simply include self (module A) into the array of modules held in @_dependencies array. Hence, we can have a ton of modules stored in @_dependencies by following the same process. Ultimately, all of the modules will be included in the first module or class that does not extend ActiveSupport::Concern. The reason why this is done is so that module dependencies will be included when the module is included in the parent class (or module). Apparently, ruby has no built in utility to accomplish dependency resolution when one module depends on others and that one module is included in a class. On Sep 20, 8:11 pm, John Merlino stoici...@aol.com wrote: 1.9.3p0 :003 class A 1.9.3p0 :004? end 1.9.3p0 :009 A.is_a?(Module) = true 1.9.3p0 :010 A.is_a?(Class) = true 1.9.3p0 :011 Class.is_a?(Module) = true class is module, so answer is append_features is run On Sep 20, 1:23 am, John Merlino stoici...@aol.com wrote: append_features(mod) The documentation says: When this module is included in another, Ruby calls append_features in this module, passing it the receiving module in mod. Ruby’s default implementation is to add the constants, methods, and module variables of this module to mod if this module has not already been added to mod or one of its ancestors. See also Module#include. What if this module is included in a class, will append_features of this module still be called, passing in the class as mod? This is in particular reference to ActiveRecord::Concern, which has its own implementation of append_features overriding ruby's. -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] Re: multiple modules defining same method included into a class
Yep: 1.9.3p0 :005 module B 1.9.3p0 :006? def name 1.9.3p0 :007? puts 'b module' 1.9.3p0 :008? end 1.9.3p0 :009? end = nil 1.9.3p0 :010 module C 1.9.3p0 :011? def name 1.9.3p0 :012? puts 'c module' 1.9.3p0 :013? end 1.9.3p0 :014? end = nil 1.9.3p0 :015 class A 1.9.3p0 :016? include B 1.9.3p0 :017? include C 1.9.3p0 :018? end = A 1.9.3p0 :019 A.new.name c module = nil On Sep 18, 9:14 am, Matt Jones al2o...@gmail.com wrote: On Monday, 17 September 2012 21:04:58 UTC-4, John Merlino wrote: In Ruby, classes are never closed: you can always add methods to an existing class. This applies to the classes you write as well as the standard, built-in classes. All you have to do is open up a class definition for an existing class, and the new contents you specify will be added to whatever's there. In the same regard, if module is used with the name of a pre-existing module that module is re-opened. If a method is defined in a re-opened module with the same name as a pre-existing method in the same module the old method is overwritten with the new. And, of course, modules can be made immutable, effectively preventing them from being reopened by freezing the module object. Frozen modules raise RuntimeErrors when methods are defined, or variables manipulated, in their context. When you include a module in a class, without a prefix (prefix meaning something like this: AbstractController::Layouts), then ruby searches for the module of that name within the scope of the current module wrapping the class that the include was called in. So, for example: module ActionController class Base include Rendering Since we include Rendering within the scope of the Base class object, ruby first looksup the constant Rendering, that is, looking for a module named Rendering in the ActionController namespace, since that is the namesapce that Base is defined in??? Well, ActionController module does define a module named Rendering: module ActionController module Rendering def render(*args) raise ::AbstractController::DoubleRenderError if response_body super self.content_type ||= Mime[lookup_context.rendered_format].to_s response_body end So now the method render(*args) is included in the Base class as an instance method. So when we call, for example, (hypothetically) ActionView::Base.new.render :action = my_action, :layout = false, ActionView::Base is instantiated and we invoke the render instance method, and since no render method is declared in the Base class context, ruby scope chain does lookup into the module Rendering and finds the method so calls it. Now, as you may know, it's possible to pass multiple kinds of arguments to render, depending on whether you want to render a template or a partial or file, etc. The * syntax does the job here, allowing you vary the number of arguments passed. It checks if there is already a response to the request, and raises an Exception, if so. Otherwise, it calls super. During this super call, I got a little confused. In ActionController::Base, there is another module included called AbstractController::Layouts. Layouts in turn includes a module called Rendering. Since there is a Rendering module within the AbstractController namespace, it is found, and it indeed contains a method called render. def render(*args, block) options = _normalize_render(*args, block) self.response_body = render_to_body(options) end And because render is included in Layouts, it's included as an instance method, and because Layouts was included in ActionController::Base, that render method utlimately makes its way up to the Base class. Now we have two modules (ActionController::Rendering and AbstractController::Rendering that are including this method into Base. So why doesn't one of them get overwritten? Why does the call to super work? The modules aren't included exactly - they're just added to the list of ancestors (try ActionController::Base.ancestors for an eyeful) where methods are looked up. Modules included later in the source are higher on the list (similar to subclass methods vs. base class methods) and calling 'super' simply specifies that the *next* available method up the chain should be called. This works (as of recent Rails versions) for generated methods as well: class SomeModel ActiveRecord::Base has_many :wats def wats # calling 'super' here hits the generated accessor from has_many end end There's one additional wrinkle for many of the modules in Rails itself - many of them are extended with ActiveSupport::Concern, which tidies a bunch of things up and (most relevant here) changes the semantics of include SomeOtherModule. See this article for more: http://opensoul.org/blog/archives/2011/02/07/concerning-activesupport... --Matt Jones -- You
[Rails] append_features(mod)
append_features(mod) The documentation says: When this module is included in another, Ruby calls append_features in this module, passing it the receiving module in mod. Ruby’s default implementation is to add the constants, methods, and module variables of this module to mod if this module has not already been added to mod or one of its ancestors. See also Module#include. What if this module is included in a class, will append_features of this module still be called, passing in the class as mod? This is in particular reference to ActiveRecord::Concern, which has its own implementation of append_features overriding ruby's. -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] Re: inheriting from StandardError
So we must build an entire class just for sake of more specific rescue
statements:
class MyError StandardError
end
try_counter = 0
begin
try_counter += 1
puts 'Here 1'
raise MyError.new Text unless try_counter 5
puts 'Here 2'
rescue MyError
puts 'Here 3 - MyError encountered'
retry
rescue StandardError
puts Here 4 - Other error encountered (#{$!.inspect}) +
caller.inspect
raise
else
puts 'Here 5 - No errors'
ensure
puts 'Here 6 - Always done'
end
On Sep 16, 4:02 pm, Frederick Cheung frederick.che...@gmail.com
wrote:
On Sunday, September 16, 2012 7:57:44 PM UTC+1, John Merlino wrote:
class ActionNotFound StandardError #:nodoc:
end
unless action_name = method_for_action(action_name)
raise ActionNotFound, The action '#{action}' could not be found for
#{self.class.name}
end
But why even bother to create the subclasses (which as shown above,
have no definition of themselves), when substituting ActionNotFound
with StandardError during the raise call will have the same effect.
Because it doesn't have the same effect. Raising specific subclasses allows
you to write targeted rescue clauses rather than rescuing indiscriminately.
Fred
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[Rails] multiple modules defining same method included into a class
In Ruby, classes are never closed: you can always add methods to an existing class. This applies to the classes you write as well as the standard, built-in classes. All you have to do is open up a class definition for an existing class, and the new contents you specify will be added to whatever's there. In the same regard, if module is used with the name of a pre-existing module that module is re-opened. If a method is defined in a re-opened module with the same name as a pre-existing method in the same module the old method is overwritten with the new. And, of course, modules can be made immutable, effectively preventing them from being reopened by freezing the module object. Frozen modules raise RuntimeErrors when methods are defined, or variables manipulated, in their context. When you include a module in a class, without a prefix (prefix meaning something like this: AbstractController::Layouts), then ruby searches for the module of that name within the scope of the current module wrapping the class that the include was called in. So, for example: module ActionController class Base include Rendering Since we include Rendering within the scope of the Base class object, ruby first looksup the constant Rendering, that is, looking for a module named Rendering in the ActionController namespace, since that is the namesapce that Base is defined in??? Well, ActionController module does define a module named Rendering: module ActionController module Rendering def render(*args) raise ::AbstractController::DoubleRenderError if response_body super self.content_type ||= Mime[lookup_context.rendered_format].to_s response_body end So now the method render(*args) is included in the Base class as an instance method. So when we call, for example, (hypothetically) ActionView::Base.new.render :action = my_action, :layout = false, ActionView::Base is instantiated and we invoke the render instance method, and since no render method is declared in the Base class context, ruby scope chain does lookup into the module Rendering and finds the method so calls it. Now, as you may know, it's possible to pass multiple kinds of arguments to render, depending on whether you want to render a template or a partial or file, etc. The * syntax does the job here, allowing you vary the number of arguments passed. It checks if there is already a response to the request, and raises an Exception, if so. Otherwise, it calls super. During this super call, I got a little confused. In ActionController::Base, there is another module included called AbstractController::Layouts. Layouts in turn includes a module called Rendering. Since there is a Rendering module within the AbstractController namespace, it is found, and it indeed contains a method called render. def render(*args, block) options = _normalize_render(*args, block) self.response_body = render_to_body(options) end And because render is included in Layouts, it's included as an instance method, and because Layouts was included in ActionController::Base, that render method utlimately makes its way up to the Base class. Now we have two modules (ActionController::Rendering and AbstractController::Rendering that are including this method into Base. So why doesn't one of them get overwritten? Why does the call to super work? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] Re: multiple modules defining same method included into a class
So it does appear that the ActionController::Rendering module does include AbstractController::Rendering, which means a call to super in the render method of ActionController::Rendering will in turn call the render method of AbstractController::Rendering. What makes this somewhat confusing is that ActionController::Rendering is included in ActionController::Base, but AbstractController::Rendering is included in ActionController::Base as well. Yet AbstractController::Rendering is also included in ActionController::Rendering. Wouldn't AbstractController::Rendering being included ActionController::Rendering and the fact that ActionController::Rendering is included in ActionController::Base make AbstractController::Rendering being included in ActionController::Base redundant? On Sep 17, 9:04 pm, John Merlino stoici...@aol.com wrote: In Ruby, classes are never closed: you can always add methods to an existing class. This applies to the classes you write as well as the standard, built-in classes. All you have to do is open up a class definition for an existing class, and the new contents you specify will be added to whatever's there. In the same regard, if module is used with the name of a pre-existing module that module is re-opened. If a method is defined in a re-opened module with the same name as a pre-existing method in the same module the old method is overwritten with the new. And, of course, modules can be made immutable, effectively preventing them from being reopened by freezing the module object. Frozen modules raise RuntimeErrors when methods are defined, or variables manipulated, in their context. When you include a module in a class, without a prefix (prefix meaning something like this: AbstractController::Layouts), then ruby searches for the module of that name within the scope of the current module wrapping the class that the include was called in. So, for example: module ActionController class Base include Rendering Since we include Rendering within the scope of the Base class object, ruby first looksup the constant Rendering, that is, looking for a module named Rendering in the ActionController namespace, since that is the namesapce that Base is defined in??? Well, ActionController module does define a module named Rendering: module ActionController module Rendering def render(*args) raise ::AbstractController::DoubleRenderError if response_body super self.content_type ||= Mime[lookup_context.rendered_format].to_s response_body end So now the method render(*args) is included in the Base class as an instance method. So when we call, for example, (hypothetically) ActionView::Base.new.render :action = my_action, :layout = false, ActionView::Base is instantiated and we invoke the render instance method, and since no render method is declared in the Base class context, ruby scope chain does lookup into the module Rendering and finds the method so calls it. Now, as you may know, it's possible to pass multiple kinds of arguments to render, depending on whether you want to render a template or a partial or file, etc. The * syntax does the job here, allowing you vary the number of arguments passed. It checks if there is already a response to the request, and raises an Exception, if so. Otherwise, it calls super. During this super call, I got a little confused. In ActionController::Base, there is another module included called AbstractController::Layouts. Layouts in turn includes a module called Rendering. Since there is a Rendering module within the AbstractController namespace, it is found, and it indeed contains a method called render. def render(*args, block) options = _normalize_render(*args, block) self.response_body = render_to_body(options) end And because render is included in Layouts, it's included as an instance method, and because Layouts was included in ActionController::Base, that render method utlimately makes its way up to the Base class. Now we have two modules (ActionController::Rendering and AbstractController::Rendering that are including this method into Base. So why doesn't one of them get overwritten? Why does the call to super work? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] inheriting from StandardError
I often see custom Exception classes inheriting from StandardError.
Errors which you can generally deal with are subclassed from
StandardError:
module AbstractController
class Error StandardError #:nodoc:
end
class ActionNotFound StandardError #:nodoc:
end
unless action_name = method_for_action(action_name)
raise ActionNotFound, The action '#{action}' could not be found for
#{self.class.name}
end
But why even bother to create the subclasses (which as shown above,
have no definition of themselves), when substituting ActionNotFound
with StandardError during the raise call will have the same effect.
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[Rails] Re: inheriting from StandardError
I would understand if there was some level of customization involved
that distinguishes it from the super class:
class DoubleRenderError Error
DEFAULT_MESSAGE = Render and/or redirect were called multiple
times in this action. Please note that you may only call render OR
redirect, and at most once per action. Also note that neither redirect
nor render terminate execution of the action, so if you want to exit
an action after redirecting, you need to do something like
\redirect_to(...) and return\.
def initialize(message = nil)
super(message || DEFAULT_MESSAGE)
end
end
But in the exampels I provided in the initial post that was not the
case. ActionNotFound, for example, had no implementation of its own.
It seems to be a waste of memory allocation.
On Sep 16, 2:57 pm, John Merlino stoici...@aol.com wrote:
I often see custom Exception classes inheriting from StandardError.
Errors which you can generally deal with are subclassed from
StandardError:
module AbstractController
class Error StandardError #:nodoc:
end
class ActionNotFound StandardError #:nodoc:
end
unless action_name = method_for_action(action_name)
raise ActionNotFound, The action '#{action}' could not be found for
#{self.class.name}
end
But why even bother to create the subclasses (which as shown above,
have no definition of themselves), when substituting ActionNotFound
with StandardError during the raise call will have the same effect.
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[Rails] formats in action view base
When you invoke ActionView::Base, it in turn invokes a LookupContext
object. The LookupContext class object has some class level macros
that builds some instance methods corresponding to a format:
register_detail(:formats) { ActionView::Base.default_formats ||
[:html, :text, :js, :css, :xml, :json] }
def self.register_detail(name, options = {}, block)
self.registered_details name
initialize = registered_details.map { |n| @details[:#{n}] =
details[:#{n}] || default_#{n} }
Accessors.send :define_method, :default_#{name}, block
Accessors.module_eval -METHOD, __FILE__, __LINE__ + 1
def #{name}
@details.fetch(:#{name}, [])
end
def #{name}=(value)
value = value.present? ? Array(value) : default_#{name}
_set_detail(:#{name}, value) if value != @details[:#{name}]
end
remove_possible_method :initialize_details
def initialize_details(details)
#{initialize.join(\n)}
end
METHOD
end
So these methods are included as instance methods via the Accessors
module. Later the LookupContext class override the formats method with
its own definition:
def formats=(values)
if values
values.concat(default_formats) if values.delete */*
if values == [:js]
values :html
@html_fallback_for_js = true
end
end
super(values)
end
1) So what was the purpose of adding a formats method to the Accessors
module and then include it into LookupContext, if it will always be
overriden by LookupContext's own implementation?
2) What is meant by expand [*/*] values in the comment # Override
formats= to expand [*/*] values which is directly above the
formats implementation on LookupContext?
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[Rails] Re: formats in action view base
that this would in turn invoke the formats method that
we included from our Accessors module to the LookupContext class.
However, the way the call chain works is that the class context is
looked up prior to the modules included into that class context. In
the class context, we actually do define the formats method, so this
gets invoked instead of the one defined in the Accessors module. Let's
say the format value we passed it was the symbol :js, representing the
ubiquitous javascript scripting language. I think */* refers to all
possible formats (please help, I'm not sure about that...). So if
values array contains the string */* in its index, then we merge
with it the returned array of default_formats, which is
[:html, :text, :js, :css, :xml, :json]. We also check if the
parameter is [:js]. If so, we add :html as fallback to :js. We also
set the @html_fallback_for_js instance variable to true, just in case
we ever need to check if we already set the html as a default to
javascript.
def formats=(values)
if values
values.concat(default_formats) if values.delete */*
if values == [:js]
values :html
@html_fallback_for_js = true
end
end
super(values)
end
7) This is where I am really unsure. We then call the same setter
method of the super class passing in our values array. The
LookupContext class does not inherit from any other class. However,
the Accessors module is included in it, which does define a formats
setter method so I think this is what gets called next. If this is the
case, then what happens next is the setter method we dynamically
created when the class was loaded gets called (which we included from
the Accessors module), and we encapsulate the value into an array. We
check if @details instance variable :formats key already has that
value, and if not then we make a copy of @details and set the value to
the :formats key. (Another question why do we make a copy?)
protected
def _set_detail(key, value)
@details = @details.dup if @details_key
@details_key = nil
@details[key] = value
end
This is my assessment of the sequence of actions. My main question is
if it's true that a call to super in an instance method will call the
method in an included module of the same name, as shown in the example
provided above, with detailed descriptions.
On Sep 15, 2:25 pm, John Merlino stoici...@aol.com wrote:
When you invoke ActionView::Base, it in turn invokes a LookupContext
object. The LookupContext class object has some class level macros
that builds some instance methods corresponding to a format:
register_detail(:formats) { ActionView::Base.default_formats ||
[:html, :text, :js, :css, :xml, :json] }
def self.register_detail(name, options = {}, block)
self.registered_details name
initialize = registered_details.map { |n| @details[:#{n}] =
details[:#{n}] || default_#{n} }
Accessors.send :define_method, :default_#{name}, block
Accessors.module_eval -METHOD, __FILE__, __LINE__ + 1
def #{name}
@details.fetch(:#{name}, [])
end
def #{name}=(value)
value = value.present? ? Array(value) : default_#{name}
_set_detail(:#{name}, value) if value != @details[:#{name}]
end
remove_possible_method :initialize_details
def initialize_details(details)
#{initialize.join(\n)}
end
METHOD
end
So these methods are included as instance methods via the Accessors
module. Later the LookupContext class override the formats method with
its own definition:
def formats=(values)
if values
values.concat(default_formats) if values.delete */*
if values == [:js]
values :html
@html_fallback_for_js = true
end
end
super(values)
end
1) So what was the purpose of adding a formats method to the Accessors
module and then include it into LookupContext, if it will always be
overriden by LookupContext's own implementation?
2) What is meant by expand [*/*] values in the comment # Override
formats= to expand [*/*] values which is directly above the
formats implementation on LookupContext?
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[Rails] calling method on base intended to simulate initialize on instances?
class A
def initialize
setup_b
setup_c
end
def b_and_c
#{@b} and #{@c}
end
private
def setup_b
@b = 'b'
end
def setup_c
@c = 'c'
end
def setup_d
@d = 'd'
end
end
a = A.new
a.instance_variable_get(@b) # = b
a.instance_variable_get(@c) # = c
a.instance_variable_get(@d) # = nil
a = A.new.b_and_c # = b and c
Now what I did above is to make a point. initialize allows us to
create some initial setup for new objects, so that when we call a
public method like b_and_c, we can expect certain values back based on
the initialization hook that must occur first. From my understanding,
modules do not have an initialize method, so then how do you simulate
it? Well, I was looking at Rails and notice this:
class Template
module Handlers
autoload :ERB, 'action_view/template/handlers/erb'
autoload :Builder, 'action_view/template/handlers/builder'
autoload :Raw, 'action_view/template/handlers/raw'
def self.extended(base)
base.register_default_template_handler :erb, ERB.new
base.register_template_handler :builder, Builder.new
base.register_template_handler :raw, Raw.new
end
@@template_handlers = {}
@@default_template_handlers = nil
def self.extensions
@@template_extensions ||= @@template_handlers.keys
end
def register_default_template_handler(extension, klass)
register_template_handler(extension, klass)
@@default_template_handlers = klass
end
def register_template_handler(extension, handler)
@@template_handlers[extension.to_sym] = handler
@@template_extensions = nil
end
class Template
extend Template::Handlers
class LookupContext
register_detail(:handlers){ Template::Handlers.extensions }
Basically, when ruby loads the Template class (I will assume that it
must be loaded prior to Handlers module or LookupContext class), it
immediately executes a class method, which is called extend, and
passes the module Handlers as the lone argument. What the extend
method does is copy the methods of the module Handlers to the Template
class as class methods. But what else happens is the self.extended
hook is immediately triggered, just as initialize is when you
instantiate a class. We pass our Template class object as the
parameter base. And we call the register_default_template_handler
method (which is now a class method of Template), passing it a
symbol :erb and an instance of ERB, which returns a string from
call(). We in turn call register_template_handler, passing in the same
two arguments. We simply append the key/value pair to the
@@template_handlers class variable, which is a hash data type, and
allows us to add a number of key/value pairs corresponding to
extensions and template types. (e.g. :erb extension corresponding to
an ERB template type). Hence, when we invoke the module method
extensions on the module, it can return a value for the
@@template_handlers class variable, since it was initialized with
values during the hook, prior to the extensions method call.
I have a few questions about this.
1) Is is true to say that the class variables of the module get
initialized prior than the extended hook. Reason why say this is that
the extended hook calls a method that expects the variable to be set
already.
2) Do all the methods of the module get copied over to base (Template
class object) prior to the hook being called? Reason why I say this is
because we call base.register_default_template_handler, where base is
Tempalte object an register_default_template_handler is defined in the
module that gets copied to base as a class method via extend. Hence,
in order for base.register_default_template_handler to work, the
methods must have been copied first.
3) Can anyone tell me what @@template_extensions is for? I dont see
that initialized with a value anywhere other than nil.
thanks for response
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[Rails] define_method vs module_eval
Rails code:
Accessors.send :define_method, :default_#{name}, block
Accessors.module_eval -METHOD, __FILE__, __LINE__ + 1
def #{name}
@details.fetch(:#{name}, [])
end
def #{name}=(value)
value = value.present? ? Array(value) : default_#{name}
_set_detail(:#{name}, value) if value != @details[:#{name}]
end
remove_possible_method :initialize_details
def initialize_details(details)
#{initialize.join(\n)}
end
METHOD
end
Here we invoke send() on the module Accessors, passing
the :define_method symbol, which represents the define_method private
method available from Class class. We create an instance method called
default_locale, whose value is the block passed from register_detail
class method of ActionView::LookupContext. Note that we later use
include Accessors within LookupContext class to make that available
as an instance method of LookupContext. We then create more instance
methods using module_eval, with here-documents to specify our
delimiter (METHOD) and the dynamic constants (__FILE__, __LINE__) for
accurate error reporting on stacktrace. My question is why not include
default_#{name} as part of the evaluated string in module_eval, rather
than invoking send() directly above that using define_method?
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[Rails] Re: mattr_accessor inside a class
it looks as if it is onyl available on the class because if you look it says self.class.fallbacks, yet that wouldnt make sense either because then what would be the point of its existance if you had to reach the class for it it, why not just create a class level macro instead? On Sep 9, 3:10 pm, John Merlino stoici...@aol.com wrote: Rails extends Ruby with mattr_accessor (Module accessor). As Ruby's attr_accessor generates getter/setter methods for instances, mattr_accessor provide getter/setter methods at the module level. In below example, you see that mattr_accessor declared in the class context of LookupContext. It's declared in class, not module. However, modules are defined in LookupContext, for example, the module ViewPaths, which makes use of the accessor. So is it safe to say that if a module accessor is declared in class, then it can only be available to modules of that class? class LookupContext mattr_accessor :fallbacks module ViewPaths self.class.fallbacks.each do |resolver| -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] Re: dash symbol
ok this was oversight on my part. First of all, instead of using the helper helper in the console, you can directly access actionview just by specifying the constant. So ActionView::Helpers::FormBuilder.instance_methods would work. But what was oversight is that I was wondering that FormBuilder's field_helpers class method which returns an array of methods for the object was actually removing all the methods it defines. But if you look at its assignment, it is grabbing the methods of FormHelper, not FormBuilder. It does FormHelper.instance_methods and FormHelper is what defines the key methods that we often invoke on the form builder that have generic output: ActionView::Helpers::FormHelper.instance_methods = [:convert_to_model, :form_for, :fields_for, :label, :text_field, :password_field, :hidden_field, :file_field, :text_area, :check_box, :radio_button, :search_field, :telephone_field, :phone_field, :url_field, :email_field, :number_field, :range_field] The reason why we exclude :label, :check_box, :radio_button, :fields_for, :hidden_field, :file_field is because they have their own unqiue definition which is done in the form builder itself. So whene we cal text_field, for example, that method was dybamically built using class_eval. and what it does is just call the method from selector.inspect on tempalte, and of course the tempalte is ActionView::Helpers::FormHelper, since that is also where form_for itself is defined. and in our view we invoke form_for, where self is ActionView with tha tmodule included. On Sep 8, 3:51 pm, John Merlino stoici...@aol.com wrote: Yeah so I would like to see the returned array of instance methods of field_helpers of FormBuilder. I try to return it in console: 1.9.3p0 :016 FormBuilder.field_helpers NoMethodError: undefined method `field_helpers' for FormBuilder:Class Why is it saying undefined method field_helpers when that method exists on the FormBuilder class: class_attribute :field_helpers On Sep 8, 2:49 pm, Jordon Bedwell envyge...@gmail.com wrote: In ruby a minus on an array removes elements. So its removing elements from the array. On Sep 8, 2012 1:42 PM, John Merlino stoici...@aol.com wrote: In the example below, what is the dash doing between the class attribute and array: (field_helpers - [:label, :check_box, :radio_button, :fields_for, :hidden_field, :file_field]).each do |selector| -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visithttps://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] What module are the % % and %= % defined in?
What module of ActionView are the % % and %= % defined in? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] Re: What module are the % % and %= % defined in?
ok ActionView::Base includes this module ::ERB::Util and ERB class seems to do so On Sep 9, 1:53 pm, John Merlino stoici...@aol.com wrote: What module of ActionView are the % % and %= % defined in? -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] mattr_accessor inside a class
Rails extends Ruby with mattr_accessor (Module accessor). As Ruby's attr_accessor generates getter/setter methods for instances, mattr_accessor provide getter/setter methods at the module level. In below example, you see that mattr_accessor declared in the class context of LookupContext. It's declared in class, not module. However, modules are defined in LookupContext, for example, the module ViewPaths, which makes use of the accessor. So is it safe to say that if a module accessor is declared in class, then it can only be available to modules of that class? class LookupContext mattr_accessor :fallbacks module ViewPaths self.class.fallbacks.each do |resolver| -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] LookupContext missing constructor
The title of this message is wrong. LookupContext must have a
constructor:
ActionView::LookupContext.new(nil)
= #ActionView::LookupContext:0x007f8e84755d18 @details_key=nil,
@details={:handlers=[:erb, :builder, :coffee], :formats=[:html, :text, :js,
:css, :ics, :csv, :xml, :rss, :atom, :yaml, :multipart_form, :url_encoded_form,
:json], :locale=[:en, :en]},
@skip_default_locale=false, @frozen_formats=false, @cache=true,
@prefixes=[], @view_paths=[]
My problem is I can't find it:
https://github.com/rails/rails/blob/master/actionpack/lib/action_view/lookup_context.rb
There's other initialize methods for other classes, but not for
LookupContext. Where is it?
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[Rails] Re: LookupContext missing constructor
I think I found it on line 170:
def initialize(view_paths, details = {}, prefixes = [])
@details, @details_key = {}, nil
@skip_default_locale = false
@cache = true
@prefixes = prefixes
@rendered_format = nil
self.view_paths = view_paths
initialize_details(details)
end
It's after 3 module definitions of the same class. It seems almost
intentionally designed to be confusing.
On Sep 9, 3:25 pm, John Merlino stoici...@aol.com wrote:
The title of this message is wrong. LookupContext must have a
constructor:
ActionView::LookupContext.new(nil)
= #ActionView::LookupContext:0x007f8e84755d18 @details_key=nil,
@details={:handlers=[:erb, :builder, :coffee], :formats=[:html, :text, :js,
:css, :ics, :csv, :xml, :rss, :atom, :yaml, :multipart_form,
:url_encoded_form, :json], :locale=[:en, :en]},
@skip_default_locale=false, @frozen_formats=false, @cache=true,
@prefixes=[], @view_paths=[]
My problem is I can't find it:
https://github.com/rails/rails/blob/master/actionpack/lib/action_view...
There's other initialize methods for other classes, but not for
LookupContext. Where is it?
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[Rails] misleading variable value
I'm going to invoke action view base from console, passing a string
object:
1.9.3p0 :016 ActionView::Base.new('app/views')
= #ActionView::Base:0x007fd95c5e8f48 @_config={},
@view_renderer=#ActionView::Renderer:0x007fd95c5e8c50
@lookup_context=#ActionView::LookupContext:0x007fd95c5e8ed0
@details_key=nil,
@details={:handlers=[:erb, :builder, :coffee], :formats=[:html, :text, :js,
:css, :ics, :csv, :xml, :rss, :atom, :yaml, :multipart_form, :url_encoded_form,
:json], :locale=[:en, :en]},
@skip_default_locale=false, @frozen_formats=false, @cache=true,
@prefixes=[], @view_paths=[/Users/johnmerlino/github/my_diet/app/
views], @_assigns={}, @_controller=nil,
@view_flow=#ActionView::OutputFlow:0x007fd95c5e8c28 @content={},
@output_buffer=nil, @virtual_path=nil
Look at the return value assigned to @view_paths. It should not be an
array. It should be a PathSet object instance, which has an instance
variable called @paths, which holds an array of
OptimizedFileSystemResolver object instances, which themselves hold a
@path instance variable that is the very string represented in that
@view_paths array above. So what's going on?
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[Rails] dash symbol
In the example below, what is the dash doing between the class attribute and array: (field_helpers - [:label, :check_box, :radio_button, :fields_for, :hidden_field, :file_field]).each do |selector| -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] Re: dash symbol
Yeah so I would like to see the returned array of instance methods of field_helpers of FormBuilder. I try to return it in console: 1.9.3p0 :016 FormBuilder.field_helpers NoMethodError: undefined method `field_helpers' for FormBuilder:Class Why is it saying undefined method field_helpers when that method exists on the FormBuilder class: class_attribute :field_helpers On Sep 8, 2:49 pm, Jordon Bedwell envyge...@gmail.com wrote: In ruby a minus on an array removes elements. So its removing elements from the array. On Sep 8, 2012 1:42 PM, John Merlino stoici...@aol.com wrote: In the example below, what is the dash doing between the class attribute and array: (field_helpers - [:label, :check_box, :radio_button, :fields_for, :hidden_field, :file_field]).each do |selector| -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visithttps://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] not seeing where name attribute is added to input fields
Without going to detail, I'll just show important code:
text field is passed the name of object, could be a symbol (:user) or
string (user[]). method is datbase attribute or virtual attribute.
the options hash, among other things, includes the object if persisted
(e.g. @user).
def text_field(object_name, method, options = {})
Tags::TextField.new(object_name, method, self, options).render
end
TextField doesn't have initialize, it calls on super which is Base,
and we create some instance variables holding our object information
and so forth:
class Base
...
def initialize(object_name, method_name, template_object,
options = {})
@object_name, @method_name = object_name.to_s.dup,
method_name.to_s.dup
@template_object = template_object
@object_name.sub!(/\[\]$/,) || @object_name.sub!(/\[\]\]
$/,])
@object = retrieve_object(options.delete(:object))
@options = options
...
We call render on text field object
def render
options = @options.stringify_keys
options[size] = options[maxlength] unless options.key?
(size)
options[type] ||= field_type
options[value] = options.fetch(value)
{ value_before_type_cast(object) } unless field_type == file
options[value] = ERB::Util.html_escape(options[value])
add_default_name_and_id(options)
tag(input, options)
end
def tag(name, options = nil, open = false, escape = true)
#{name}#{tag_options(options, escape) if options}#{open ?
: /}.html_safe
end
and thats pretty much it. Wheres the name attribute and its value
appended to the returned string from render?
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[Rails] :index = nil
On here: http://api.rubyonrails.org/classes/ActionView/Helpers/FormHelper.html#method-i-check_box-label-Gotcha you see this code: %= fields_for project[invoice_attributes][], invoice, :index = nil do |form| % %= form.check_box :paid % ... % end % why are they using :index = nil in the example? I mean I know that what it does is ensure that the invoice objects do not get passed an index number so that you have this: project[invoice_attributes][] rather than this: project[invoice_attributes][1]. But why in the above example, do they want to achieve this? It seems as though invoice is an existing object and therefore is not a new record. -- You received this message because you are subscribed to the Google Groups Ruby on Rails: Talk group. To post to this group, send email to rubyonrails-talk@googlegroups.com. To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
[Rails] Re: Regexp pre_match
yep, last_match returns a MatchData object, which contains some
wrapper methods, including a string of the last successful pattern
match. Hence, pre_match would fall under MatchData, not Regexp.
On Sep 6, 10:21 am, Rick richard.t.ll...@gmail.com wrote:
http://www.ruby-doc.org/core-1.9.3/MatchData.html#method-i-pre_match
On Thursday, September 6, 2012 1:40:31 AM UTC-4, John Merlino wrote:
I looked in ruby documentation
http://www.ruby-doc.org/core-1.9.3/Regexp.html
I cannot find a method called pre_match but its used in Rails...
@template.instance_variable_get(@#{Regexp.last_match.pre_match})
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