How to resolve properly exception
Hi,
How can I write exception with Perl ?
Any thing like this:
If (Application generate Error)
{
message_html('Error ')
}
Thanks
KN
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Re: How to resolve properly exception
on Fri, 14 Feb 2003 12:38:16 GMT, [EMAIL PROTECTED] (Khalid Naji) wrote: How can I write exception with Perl ? See, e.g., Object Oriented Exception Handling in Perl by Arun Udaya Shankar, available at http://www.perl.com/pub/a/2002/11/14/exception.html -- felix -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
chatroom
Hello all, I'm in the process of writing a cgi based chatroom, and I need to figure out a way to tell who is currently logged in the chatroom. The web page is a frameset with three frames: the first one has a listing of the chatrooms you can go to, the second is the actual chatroom itself which is just an html page with a meta content refresh tag on it (refreshes every 5 seconds), and the last frame has the form where you type in the text to be displayed in the html page. The form simply rewrites the html file with the new text. The users of this chatroom actually log in via apache. I've thought about making the html file a perl script that can grab the env var that holds the name of the person using the browser. The script could update another flat file stating that the person's browser refreshed the page. I can then come up with some way to tell if a person has refreshed within the last 5 to 10 seconds, and if he/she hasn't, then I can say that the person has logged out. I'm not very experienced with cookies, but I'm kind of guessing that there may be an easier way to do this using cookies. Any help is appreciated. Thanks! -Stephen Spalding __ Do you Yahoo!? Yahoo! Shopping - Send Flowers for Valentine's Day http://shopping.yahoo.com -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
DBI question
Hi List,
Sorry if this is a little offtopic but I'm trying to learn DBI for a
CGI I'm writing. Been reading http://www.perldoc.com/cpan/DBI.html but
seems a little over complex for what I need...just inserts, updates, and
queries really. Portability isn't too important. Probably going to use
DBD::ODBC on top of it anyway. Also trying to learn about packages and OOP
with perl at the same time...yikes.
Basically, i'm trying to write a little abstraction layer so that I can say
things like:
$dbh = MyPackages::DB-new(); #handles my connection stuff.
#and then
my @values = $dbh-getvalues(username,users);
#or maybe,
my @rowsHashRefs = @{$dbh-query(select username,email from users)};
#and then
foreach my $hashRef (@rowsHashRefs){
my %row = %{$hashRef};
#some html...
print user $row{'username'}'s email is $row{'email'};
#or whatever
}
Not sure how much code I'm actually saving by doing this...Does anybody have
experience using DBI or any tricks for keeping things simple and avoiding
excessive prepare, execute, selectall_hashrefs...etc.
Secondly, I thought I had something working (see my package below) but
it's complaining that I'm only passing one argument to selectall_hashref
despite the documentation saying you can use just a simple statement.
here's the error: Usage: $h-selectall_hashref($statement, $keyfield [,
\%attr [, @bind_params ] ]) at Score/DB.pm line 56.
Thanks for any pointers...
-peter
here's the package that I'm trying to write: (be warned: It's ugly)
use strict;
use DBI;
use DBD::ODBC;
package MyPackages::DB;
sub new {
#my $class=shift;
my $self={};
bless $self;
#go ahead and connect
$self-connect();
return $self;
}
sub connect{
my $self = shift;
$self-{dbh} =
DBI-connect(dbi:ODBC:myDSN,username,sekretpassword,{
AutoCommit=0,
RaiseError=1}) or die(Can't connect! $!);
}
sub getValue{
my ($self,$field,$table,$condition) = @_;
return if($#_2);
my @rowHashRefs;
if($condition){
@rowHashRefs = @{$self-query(Select $field from $table
where $condition)};
}else{
@rowHashRefs = @{$self-query(select $field from $table)};
}
#get at our hash from our arrayref [0] and pull out the value of
field:$field
#if ($#rowHasheRefs == 0){
# return ${${$arrayRef}[0]}{$field};
#}
my @fieldValues;
foreach my $rowHashRef (@rowHashRefs){
push(@fieldValues,${$rowHashRef}{$field});
}
#give back the array of values ...or do I want a reference to it?
return @fieldValues;
}
sub query{
my ($self,$qry) = @_;
return unless($qry);
return $self-{dbh}-selectall_hashref($qry); #why does it complain
here
}
1;
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RE: DBI question
Basically, i'm trying to write a little abstraction layer
Someone already did the work for you, check out Class::DBI.
Here is a good article on it, it might be all you need.
http://www.perl.com/pub/a/2002/11/27/classdbi.html
Rob
-Original Message-
From: Peter Kappus [mailto:[EMAIL PROTECTED]]
Sent: Friday, February 14, 2003 3:59 PM
To: CGI
Subject: DBI question
Hi List,
Sorry if this is a little offtopic but I'm trying to learn DBI for a
CGI I'm writing. Been reading http://www.perldoc.com/cpan/DBI.html but
seems a little over complex for what I need...just inserts, updates, and
queries really. Portability isn't too important. Probably going to use
DBD::ODBC on top of it anyway. Also trying to learn about packages and OOP
with perl at the same time...yikes.
Basically, i'm trying to write a little abstraction layer so that I can say
things like:
$dbh = MyPackages::DB-new(); #handles my connection stuff.
#and then
my @values = $dbh-getvalues(username,users);
#or maybe,
my @rowsHashRefs = @{$dbh-query(select username,email from users)};
#and then
foreach my $hashRef (@rowsHashRefs){
my %row = %{$hashRef};
#some html...
print user $row{'username'}'s email is $row{'email'};
#or whatever
}
Not sure how much code I'm actually saving by doing this...Does anybody have
experience using DBI or any tricks for keeping things simple and avoiding
excessive prepare, execute, selectall_hashrefs...etc.
Secondly, I thought I had something working (see my package below) but
it's complaining that I'm only passing one argument to selectall_hashref
despite the documentation saying you can use just a simple statement.
here's the error: Usage: $h-selectall_hashref($statement, $keyfield [,
\%attr [, @bind_params ] ]) at Score/DB.pm line 56.
Thanks for any pointers...
-peter
here's the package that I'm trying to write: (be warned: It's ugly)
use strict;
use DBI;
use DBD::ODBC;
package MyPackages::DB;
sub new {
#my $class=shift;
my $self={};
bless $self;
#go ahead and connect
$self-connect();
return $self;
}
sub connect{
my $self = shift;
$self-{dbh} =
DBI-connect(dbi:ODBC:myDSN,username,sekretpassword,{
AutoCommit=0,
RaiseError=1}) or die(Can't connect! $!);
}
sub getValue{
my ($self,$field,$table,$condition) = @_;
return if($#_2);
my @rowHashRefs;
if($condition){
@rowHashRefs = @{$self-query(Select $field from $table
where $condition)};
}else{
@rowHashRefs = @{$self-query(select $field from $table)};
}
#get at our hash from our arrayref [0] and pull out the value of
field:$field
#if ($#rowHasheRefs == 0){
# return ${${$arrayRef}[0]}{$field};
#}
my @fieldValues;
foreach my $rowHashRef (@rowHashRefs){
push(@fieldValues,${$rowHashRef}{$field});
}
#give back the array of values ...or do I want a reference to it?
return @fieldValues;
}
sub query{
my ($self,$qry) = @_;
return unless($qry);
return $self-{dbh}-selectall_hashref($qry); #why does it complain
here
}
1;
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Perl problem:(
Hello all:)
You have been greaet helps to me in the past, and im hoping you can help now:) A
friend of mine is
in a class learning perl and her script keeps getting an error that there is a bracket
missing on
line 190. When i looked at it, all i could see was the nested statement problem i had
at one time.
Do you think that is the problem? and if so, what would be the best way to fix it? I
want her to
be able to learn it, not to have it done for her, but i want to give her the best
advice possible:
Script:::
#!/usr/bin/perl
#
# lab3.pl
#
my @scorearray;
sub getinformation()
{
local $score = 0;
local $total = 0;
local $ctr = 0;
local $rpt_ctr = 0;
open (OUTFILE, info.txt)
|| die cannot open info.txt $!;
local $var = bad;
while ($var eq bad)
{
print enter student's first name: ;
$firstname = STDIN;
chop ($firstname);
$length = length($firstname);
if (!$length)
{
print Not a valid First Name, try again.\n;
next;
{
if($length 20)
{
print Not a valid First Name, try again. \n;
next;
}
if($length)
{
$var = good;
print (OUTFILE $firstname|);
}
}
local $var1 = bad;
while ($var1 eq bad)
{
print enter student's last name: ;
$lastname = STDIN;
chop ($lastname);
if (!$length1)
{
print Not a valid last name, try again. \n;
next;
}
if($length1 20)
{
print Not a valid last name, try again. \n;
next;
}
if($length1)
{
$var1 = good;
print(OUTFILE $lastname|);
}
}
local $var2 = bad;
while($var2 = bad)
{
print enter student's SSN:;
$ssn = STDIN;
chop($ssn);
$length2=length($ssn);
if(!$length2)
{
print Not a valid Social Security Number, try again.\n;
next;
}
$ssn =~ s/[^\d]//g;
if($ssn !~ m/^\d{9}$/)
{
print Not a valid Social Security Number, try again.\n;
next;
}
if($ssn =~ m/^\d{9}$/)
{
$var2 = good;
print(OUTFILE $ssn);
}
}
local $ctr1 = 1;
while ($ctr 4)
{
print enter a test score $ctr1: ;
$score = STDIN;
chop ($score);
if ($score eq q)
{
last;
}
local $error = true;
testscore($score);
if ($error eq false)
{
next;
}
else
{
$total += $score;
$ctr++;
$ctr1++;
$scorearray[$ctr]=$score;
}
};
while($rpt_ctr = $ctr)
{
print (OUTFILE $scorearray[$rpt_ctr]);
if($rpt_ctr 3)
{
print(OUTFILE |);
}
$rpt_ctr++;
}
print (OUTFILE \n);
getscore();
};
sub getscore()
{
local $display = 4 - $ctr;
local $avg = $total / 4;
print Score total is $total \n;
print number of scores entered is $ctr \n;
print Score Average is $avg \n;
print $firstname is missing $display tests\n;
warnings();
};
sub testscore()
{
if ($score 100)
{
print invalid score, please make sure the score is less than or equal
to 100\n;
$error = false;
}
if ($score 0)
{
print invalid score, please make sure the score is greater than or
equal to 0\n;
$error = false;
}
};
sub warnings()
{
if ($avg = 60)
{
print Grim Warning, $firstname !;
}
elsif ($avg = 70)
{
print Uh-oh! You maybe in trouble, $firstname !;
}
elsif ($avg = 80)
{
print Good going $firstname \n You have a
RE: Perl problem:(
First if statement.
$length = length($firstname);
if (!$length)
{
print Not a valid First Name, try again.\n;
next;
---{
Greg Smith
-Original Message-
From: t [mailto:[EMAIL PROTECTED]]
Sent: Friday, February 14, 2003 4:05 PM
To: [EMAIL PROTECTED]
Subject: Perl problem:(
Hello all:)
You have been greaet helps to me in the past, and im hoping you
can help now:) A friend of mine is
in a class learning perl and her script keeps getting an error
that there is a bracket missing on
line 190. When i looked at it, all i could see was the nested
statement problem i had at one time.
Do you think that is the problem? and if so, what would be the
best way to fix it? I want her to
be able to learn it, not to have it done for her, but i want to
give her the best advice possible:
Script:::
#!/usr/bin/perl
#
# lab3.pl
#
my @scorearray;
sub getinformation()
{
local $score = 0;
local $total = 0;
local $ctr = 0;
local $rpt_ctr = 0;
open (OUTFILE, info.txt)
|| die cannot open info.txt $!;
local $var = bad;
while ($var eq bad)
{
print enter student's first name: ;
$firstname = STDIN;
chop ($firstname);
$length = length($firstname);
if (!$length)
{
print Not a valid First Name, try again.\n;
next;
{
if($length 20)
{
print Not a valid First Name, try again. \n;
next;
}
if($length)
{
$var = good;
print (OUTFILE $firstname|);
}
}
local $var1 = bad;
while ($var1 eq bad)
{
print enter student's last name: ;
$lastname = STDIN;
chop ($lastname);
if (!$length1)
{
print Not a valid last name, try again. \n;
next;
}
if($length1 20)
{
print Not a valid last name, try again. \n;
next;
}
if($length1)
{
$var1 = good;
print(OUTFILE $lastname|);
}
}
local $var2 = bad;
while($var2 = bad)
{
print enter student's SSN:;
$ssn = STDIN;
chop($ssn);
$length2=length($ssn);
if(!$length2)
{
print Not a valid Social Security Number,
try again.\n;
next;
}
$ssn =~ s/[^\d]//g;
if($ssn !~ m/^\d{9}$/)
{
print Not a valid Social Security Number,
try again.\n;
next;
}
if($ssn =~ m/^\d{9}$/)
{
$var2 = good;
print(OUTFILE $ssn);
}
}
local $ctr1 = 1;
while ($ctr 4)
{
print enter a test score $ctr1: ;
$score = STDIN;
chop ($score);
if ($score eq q)
{
last;
}
local $error = true;
testscore($score);
if ($error eq false)
{
next;
}
else
{
$total += $score;
$ctr++;
$ctr1++;
$scorearray[$ctr]=$score;
}
};
while($rpt_ctr = $ctr)
{
print (OUTFILE $scorearray[$rpt_ctr]);
if($rpt_ctr 3)
{
print(OUTFILE |);
}
$rpt_ctr++;
}
print (OUTFILE \n);
getscore();
};
sub getscore()
{
local $display = 4 - $ctr;
local $avg = $total / 4;
print Score total is $total \n;
print number of scores entered is $ctr \n;
print Score Average is $avg \n;
print $firstname is missing $display tests\n;
warnings();
};
sub testscore()
{
if ($score 100)
{
print invalid score, please make sure the score is
less than or equal to 100\n;
$error = false;
}
if ($score 0)
{
print invalid score, please make sure the score is
greater than or equal to 0\n;
$error = false;
}
};
Re: Perl problem:(
t wrote:
Hello all:)
You have been greaet helps to me in the past, and im hoping you can help now:) A friend of mine is
in a class learning perl and her script keeps getting an error that there is a bracket missing on
line 190. When i looked at it, all i could see was the nested statement problem i had at one time.
Do you think that is the problem? and if so, what would be the best way to fix it? I want her to
be able to learn it, not to have it done for her, but i want to give her the best advice possible:
Time to start reading ;-)
perldoc -f chomp
perldoc -f chop
perldoc -f my
perldoc -f our
perldoc -f local
2 rules first off...
Don't ever use 'chop'...at least not until you know why you should never
use chop, then you can
Don't ever use 'local'...at least not until you know why you should
never use local, then you can ;-)
http://perl.plover.com/FAQs/Namespaces.html
Where is the:
use strict;
use warnings;
???
perldoc perlstyle (wouldn't hurt to have a glance at)
1. Don't need semi-colons after sub routine definitions or other blocks.
2. In general it is considered ok to put the 'main' of a Perl program
into the actual 'main' rather than in a subroutine that is the only
thing called.
3. In general the main of Perl goes before the sub definitions.
4. Don't want (need) empty parenthesis in a sub definition, I am not
sure but this might actually force the sub to not allow args?
5. warnings is a VERY bad name for a subroutine, don't use it.
6. Multiple if statements involving the same parameter(s) can be chained
using 'elsif'.
7. Very seldom should you use the same exact error/warning message
twice, this will make debugging a nightmare, tell the user what they
screwed up, yell it at them if it helps ;-)...
8. Return something from subroutines, test that return code.
9. Don't get frustrated, don't quit
Script:::
#!/usr/bin/perl
#
# lab3.pl
#
my @scorearray;
sub getinformation()
{
local $score = 0;
local $total = 0;
local $ctr = 0;
local $rpt_ctr = 0;
open (OUTFILE, info.txt)
|| die cannot open info.txt $!;
local $var = bad;
while ($var eq bad)
{
print enter student's first name: ;
$firstname = STDIN;
chop ($firstname);
$length = length($firstname);
if (!$length)
{
print Not a valid First Name, try again.\n;
next;
{
Right here is your bad brace.
if($length 20)
There is much much worse code in production environments, so don't get
discouraged at the amount I picked on, tough love
http://danconia.org
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php like behavior for my perl CGI...and DBI followup
Thanks to Rob for his Class::DBI suggestion earlier. Looks like what I
needed was simply:
my %hash;
return $sth-fetchall_arrayref(\%hash);
to return an array of hashes...
As I'm continuing with my latest project, I'm finding myself wishing I could
do some PHP type things...specifically, as I'm formatting the HTML there's
often a need to throw in spacer gifs of various dimensions to make things
look pretty...
In PHP this can be streamlined by creating a function which prints out your
image tag for your and accepts the height and width as parameters. like so:
function spacer($y,$x){
?img src=spacer.gif height=?=$y? width=?=$x??
}
To call it, you would just say:
?spacer(10,50)?
and it would throw in an image tag with a height of 10 and a width of
50...or whatever.
My question is this:
i'd like to be able to use the printeof; behavior to send large blocks
of HTML to the browser. Is there A way that I can reroute that statement to
send my string through a sub that basically does the following:
sub sendit{
my $txt = shift;
$txt =~ s/\?(.+?)\?/(?{eval($1)})/g; #evaluate what's between my
?? delimeters and print the result
print $txt;
}
I know I could say:
my $vareof;
some HTML with some
PHP-type function in it?someSub(50)?
haha!
eof
sendit($var);
BUT that seems like a lot to type...I wish I could just say:
senditeof;
somHTML with some
PHP-type function in it?someSub(50)?
haha!
eof
and have sendit() parse and execute my ?? piece and print the result.
But, alas, that seems to start a never ending perl child...
Thanks once again for any sage wisdom you may have.
-peter
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