Re: Persistant references [was] Persistent Net::Telnet Objects
First, there is no way to effectively pass compiled code between
processes at this time. It isn't likely to happen with Perl 5 because
attempts at loading compiled bytecode from disk have usually had poor
performance and other issues.
Second, what you're proposing is probably not a good idea unless this is
for a small in-house project.
What I mean is, if a request comes in for a certain form I would like to be
able to do something like this:
my $form = load_form($r);
$c{$session_id}-{handler} = $form-{handler}; # -- this being a code
ref...
$r-send_http_header;
print $form;
Then when the user completes the form and resubmits:
my $handler = $c{$session_id}-{handler};
$r-send_http_header;
print $handler-($r);
What if the same user has multiple browser windows open and starts on a
new form before finishing the existing form? Remember, sessions are
global to all browser windows.
The right thing to do here is pass the form data the old-hasioned way,
in URLs or form fields. Those are distinct for each browser window.
I would like to be able to dynamically create anonymous
subroutine handlers based on input and have them be active until the form is
submitted, at which time they are used to process the form then discarded.
But why go to all that trouble, generating subroutines on the fly? It
just doesn't seem necessary for processing form input.
- Perrin
Re: Persistant references [was] Persistent Net::Telnet Objects
I have thought about this, and it's something I'm willing to do if I have
to. I would much rather be able to store an actual code ref and avoid the
overhead of many string-form eval's. Is there no way to do this?
-- Ryan
- Original Message -
From: Garth Winter Webb [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Wednesday, May 29, 2002 11:16 PM
Subject: Re: Persistant references [was] Persistent Net::Telnet Objects
You could just pass around a string rather than a subref:
my $handler = 'sub { my $arg = @_; do_something(); }';
vs
my $handler = sub { my $arg = @_; do_something(); };
When you want to call it later on you do it like:
eval($handler)-('foo');
vs
$handler-('foo');
Garth
On Wed, 2002-05-29 at 22:17, Ryan Parr wrote:
I never do give enough info on the first e-mail. Thank you for bearing
with
me...
What I mean is, if a request comes in for a certain form I would like to
be
able to do something like this:
my $form = load_form($r);
$c{$session_id}-{handler} = $form-{handler}; # -- this being a code
ref...
$r-send_http_header;
print $form;
Then when the user completes the form and resubmits:
my $handler = $c{$session_id}-{handler};
$r-send_http_header;
print $handler-($r);
This is definately simplified, but the idea is there. I would like to be
able to store anything that can be referenced and have it be available
to
all processes. I would like to be able to dynamically create anonymous
subroutine handlers based on input and have them be active until the
form is
submitted, at which time they are used to process the form then
discarded.
Is this something that can be accomplished? The global hash using Perl
aliasing
(http://thingy.kcilink.com/modperlguide/perl/Using_the_Perl_Aliasing_Feature
_.html) works beautifully, until of course the form is submitted to
another
httpd process, and I'm hoping to not have to limit myself to just one
child.
Obviously this can't be serialized, but there has to be *some* way to do
this...
-- Ryan
- Original Message -
From: Ryan Parr [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Wednesday, May 29, 2002 9:16 PM
Subject: Persistant references [was] Persistent Net::Telnet Objects
Along these same lines I'm seeking a way to store a code reference
into a
global hash that is shared among all processes. For example:
my $session_id = get_session_from_cookie($r);
my $handler = $c{$session_id}-{handler};
$r-send_http_header;
print $handler-($r);
return OK;
Has anyone performed this kind of magical tidbit before? Is there some
main
process repository that I can access?
-- Ryan
- Original Message -
From: Rob Mueller (fastmail) [EMAIL PROTECTED]
To: French, Shawn [EMAIL PROTECTED]; [EMAIL PROTECTED]
Sent: Wednesday, May 29, 2002 5:35 PM
Subject: Re: Persistent Net::Telnet Objects
Our project needed persistent socket connections open as well. There
is
supposed to be a standard mechanism to pass file descriptors between
unix
processes, though it's bugginess level depends on your OS. There is
a
perl
module for this called Socket::PassAccessRights. So what you can do
is
create a daemon process that just hangs round holding socket
connections
open, like a socket cache basically, and passing them back and forth
between
Apache processes based on some session ID or user ID or the like.
Your daemon ends up looking something like this (with lots more
error
checking of course)
my %sockmap;
while (1) {
my $clientsock = $listen-accept();
chomp(my $sessionid = $clientsock);
my $cachesock = ($sockmap{$sessionid} ||= opennewsock());
Socket::PassAccessRights::sendfd(fileno($clientsock),
fileno($cachesock));
$clientsock-close();
}
And in your mod_perl code you do something like:
my $serversock = IO::Socket::INET-new(Server = 'localhost', Port
=
SOCKETPOOLPORT);
print $serversock $sessionid, \n;
my $Fd = Socket::PassAccessRights::recvfd(fileno($serversock));
open(my $realsocket, =$Fd);
fcntl($realsocket, F_SETFD, 0);
my $ofh = select($realsocket); $| = 1; select ($ofh);
If you do some experimenting, you'll get something that works,
you'll
also
find lots of cases that don't.
Rob
- Original Message -
From: French, Shawn [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Thursday, May 30, 2002 3:53 AM
Subject: Persistent Net::Telnet Objects
Vitals:
Apache/1.3.20 (Win32) mod_perl/1.25_01-dev mod_ssl/2.8.4
OpenSSL/0.9.6a
on
Windows 2000 with PHP 4.21
I am working on a project that requires me to have two telnet
objects
per
user session opened, and accessible throughout the user's session.
I
have
looked at Apache::Session and many other solutions
Re: Persistant references [was] Persistent Net::Telnet Objects
I never do give enough info on the first e-mail. Thank you for bearing with
me...
What I mean is, if a request comes in for a certain form I would like to be
able to do something like this:
my $form = load_form($r);
$c{$session_id}-{handler} = $form-{handler}; # -- this being a code
ref...
$r-send_http_header;
print $form;
Then when the user completes the form and resubmits:
my $handler = $c{$session_id}-{handler};
$r-send_http_header;
print $handler-($r);
This is definately simplified, but the idea is there. I would like to be
able to store anything that can be referenced and have it be available to
all processes. I would like to be able to dynamically create anonymous
subroutine handlers based on input and have them be active until the form is
submitted, at which time they are used to process the form then discarded.
Is this something that can be accomplished? The global hash using Perl
aliasing
(http://thingy.kcilink.com/modperlguide/perl/Using_the_Perl_Aliasing_Feature
_.html) works beautifully, until of course the form is submitted to another
httpd process, and I'm hoping to not have to limit myself to just one child.
Obviously this can't be serialized, but there has to be *some* way to do
this...
-- Ryan
- Original Message -
From: Ryan Parr [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Wednesday, May 29, 2002 9:16 PM
Subject: Persistant references [was] Persistent Net::Telnet Objects
Along these same lines I'm seeking a way to store a code reference into a
global hash that is shared among all processes. For example:
my $session_id = get_session_from_cookie($r);
my $handler = $c{$session_id}-{handler};
$r-send_http_header;
print $handler-($r);
return OK;
Has anyone performed this kind of magical tidbit before? Is there some
main
process repository that I can access?
-- Ryan
- Original Message -
From: Rob Mueller (fastmail) [EMAIL PROTECTED]
To: French, Shawn [EMAIL PROTECTED]; [EMAIL PROTECTED]
Sent: Wednesday, May 29, 2002 5:35 PM
Subject: Re: Persistent Net::Telnet Objects
Our project needed persistent socket connections open as well. There is
supposed to be a standard mechanism to pass file descriptors between
unix
processes, though it's bugginess level depends on your OS. There is a
perl
module for this called Socket::PassAccessRights. So what you can do is
create a daemon process that just hangs round holding socket connections
open, like a socket cache basically, and passing them back and forth
between
Apache processes based on some session ID or user ID or the like.
Your daemon ends up looking something like this (with lots more error
checking of course)
my %sockmap;
while (1) {
my $clientsock = $listen-accept();
chomp(my $sessionid = $clientsock);
my $cachesock = ($sockmap{$sessionid} ||= opennewsock());
Socket::PassAccessRights::sendfd(fileno($clientsock),
fileno($cachesock));
$clientsock-close();
}
And in your mod_perl code you do something like:
my $serversock = IO::Socket::INET-new(Server = 'localhost', Port =
SOCKETPOOLPORT);
print $serversock $sessionid, \n;
my $Fd = Socket::PassAccessRights::recvfd(fileno($serversock));
open(my $realsocket, =$Fd);
fcntl($realsocket, F_SETFD, 0);
my $ofh = select($realsocket); $| = 1; select ($ofh);
If you do some experimenting, you'll get something that works, you'll
also
find lots of cases that don't.
Rob
- Original Message -
From: French, Shawn [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Thursday, May 30, 2002 3:53 AM
Subject: Persistent Net::Telnet Objects
Vitals:
Apache/1.3.20 (Win32) mod_perl/1.25_01-dev mod_ssl/2.8.4
OpenSSL/0.9.6a
on
Windows 2000 with PHP 4.21
I am working on a project that requires me to have two telnet objects
per
user session opened, and accessible throughout the user's session. I
have
looked at Apache::Session and many other solutions but my problem is
that
to
keep a Net::Telnet object, I need to keep open sockets and
filehandles,
so
I
cannot serialize the object and store it in a database or file.
Currently I have similar code working flawlessly:
###
# startup.pl - called when apache starts (ie. PerlRequire
d:/Apache/conf/startup.pl)
##
use MySite::Session;
###
# Session.pm
##
@EXPORT = qw( %sessionHash );
our %sessionHash;
###
# init_session.pl - called IN MOD_PERL when a new session is
requested
##
use MySite::Session;
$sessionHash{$session_id . _telnetObj} = Net::Telnet-new();
###
# dostuff.pl - called IN MOD_PERL many time throughout the session
##
use MySite::Session;
my telnetObj = $sessionHash{$session_id . _telnetObj};
bless (\$telnetObj, Net::Telnet);
Although this is working right now, I don't know enough [ anything?
:) ]
about Apache or mod_perl to be sure that this will work in the future.
What
I am really concerned
Re: Persistant references [was] Persistent Net::Telnet Objects
You could just pass around a string rather than a subref:
my $handler = 'sub { my $arg = @_; do_something(); }';
vs
my $handler = sub { my $arg = @_; do_something(); };
When you want to call it later on you do it like:
eval($handler)-('foo');
vs
$handler-('foo');
Garth
On Wed, 2002-05-29 at 22:17, Ryan Parr wrote:
I never do give enough info on the first e-mail. Thank you for bearing with
me...
What I mean is, if a request comes in for a certain form I would like to be
able to do something like this:
my $form = load_form($r);
$c{$session_id}-{handler} = $form-{handler}; # -- this being a code
ref...
$r-send_http_header;
print $form;
Then when the user completes the form and resubmits:
my $handler = $c{$session_id}-{handler};
$r-send_http_header;
print $handler-($r);
This is definately simplified, but the idea is there. I would like to be
able to store anything that can be referenced and have it be available to
all processes. I would like to be able to dynamically create anonymous
subroutine handlers based on input and have them be active until the form is
submitted, at which time they are used to process the form then discarded.
Is this something that can be accomplished? The global hash using Perl
aliasing
(http://thingy.kcilink.com/modperlguide/perl/Using_the_Perl_Aliasing_Feature
_.html) works beautifully, until of course the form is submitted to another
httpd process, and I'm hoping to not have to limit myself to just one child.
Obviously this can't be serialized, but there has to be *some* way to do
this...
-- Ryan
- Original Message -
From: Ryan Parr [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Wednesday, May 29, 2002 9:16 PM
Subject: Persistant references [was] Persistent Net::Telnet Objects
Along these same lines I'm seeking a way to store a code reference into a
global hash that is shared among all processes. For example:
my $session_id = get_session_from_cookie($r);
my $handler = $c{$session_id}-{handler};
$r-send_http_header;
print $handler-($r);
return OK;
Has anyone performed this kind of magical tidbit before? Is there some
main
process repository that I can access?
-- Ryan
- Original Message -
From: Rob Mueller (fastmail) [EMAIL PROTECTED]
To: French, Shawn [EMAIL PROTECTED]; [EMAIL PROTECTED]
Sent: Wednesday, May 29, 2002 5:35 PM
Subject: Re: Persistent Net::Telnet Objects
Our project needed persistent socket connections open as well. There is
supposed to be a standard mechanism to pass file descriptors between
unix
processes, though it's bugginess level depends on your OS. There is a
perl
module for this called Socket::PassAccessRights. So what you can do is
create a daemon process that just hangs round holding socket connections
open, like a socket cache basically, and passing them back and forth
between
Apache processes based on some session ID or user ID or the like.
Your daemon ends up looking something like this (with lots more error
checking of course)
my %sockmap;
while (1) {
my $clientsock = $listen-accept();
chomp(my $sessionid = $clientsock);
my $cachesock = ($sockmap{$sessionid} ||= opennewsock());
Socket::PassAccessRights::sendfd(fileno($clientsock),
fileno($cachesock));
$clientsock-close();
}
And in your mod_perl code you do something like:
my $serversock = IO::Socket::INET-new(Server = 'localhost', Port =
SOCKETPOOLPORT);
print $serversock $sessionid, \n;
my $Fd = Socket::PassAccessRights::recvfd(fileno($serversock));
open(my $realsocket, =$Fd);
fcntl($realsocket, F_SETFD, 0);
my $ofh = select($realsocket); $| = 1; select ($ofh);
If you do some experimenting, you'll get something that works, you'll
also
find lots of cases that don't.
Rob
- Original Message -
From: French, Shawn [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Thursday, May 30, 2002 3:53 AM
Subject: Persistent Net::Telnet Objects
Vitals:
Apache/1.3.20 (Win32) mod_perl/1.25_01-dev mod_ssl/2.8.4
OpenSSL/0.9.6a
on
Windows 2000 with PHP 4.21
I am working on a project that requires me to have two telnet objects
per
user session opened, and accessible throughout the user's session. I
have
looked at Apache::Session and many other solutions but my problem is
that
to
keep a Net::Telnet object, I need to keep open sockets and
filehandles,
so
I
cannot serialize the object and store it in a database or file.
Currently I have similar code working flawlessly:
###
# startup.pl - called when apache starts (ie. PerlRequire
d:/Apache/conf/startup.pl)
##
use MySite::Session;
###
# Session.pm
##
@EXPORT = qw( %sessionHash );
our %sessionHash;
###
# init_session.pl - called IN MOD_PERL when a new session
