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LWP::UserAgent::POE 0.05
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NAME
LWP::UserAgent::POE - Drop-in LWP::UserAgent replacement in POE
environments
SYNOPSIS
use LWP::UserAgent::POE;
my $ua = LWP::UserAgent::POE->new();
# The following command looks (and behaves) like it's blocking,
# but it actually keeps the POE kernel ticking and processing
# other tasks. post() and request() work as well.
my $resp = $ua->get( "http://www.yahoo.com" );
if($resp->is_success()) {
print $resp->content();
} else {
print "Error: ", $resp->message(), "\n";
}
POE::Kernel->run();
DESCRIPTION
LWP::UserAgent::POE is a subclass of LWP::UserAgent and works well in a
POE environment. It is a drop-in replacement for LWP::UserAgent in
systems that are already using LWP::UserAgent synchronously and want to
play nicely with POE.
The problem: LWP::UserAgent by itself is synchronous and blocks on
requests until the response from the network trickles in. This is
unacceptable in POE, as the POE kernel needs to continue processing
other tasks until the HTTP response arrives.
LWP::UserAgent::POE to the rescue. Its request() method and all related
methods like get(), post() etc. work just like in the original. But if
you peek under the hood, they're sending a request to a running
POE::Component::Client::HTTP component and return a valid $response
object when a response from the network is available. Although the
program flow seems to be blocked, it's not. LWP::UserAgent::POE works
the magic behind the scenes to keep the POE kernel ticking and process
other tasks.
The net effect is that you can use LWP::UserAgent::POE just like
LWP::UserAgent in a seemingly synchronous way.
Note that this module is not a POE component. Instead, it is a subclass
of LWP::UserAgent. It is self-contained, it even spawns the
POE::Component::Client::HTTP component in its constructor unless there's
one already running that has been started by another instance.
Cookies and other features
Just like LWP::UserAgent, LWP::UserAgent::POE supports cookies if you
define a cookie jar:
my $ua = LWP::UserAgent::POE->new(
cookie_jar => HTTP::Cookies->new(),
);
Just make sure to pass these parameters to the constructor, see the
'Bugs' section below on what hasn't been implemented yet.
Bugs
Currently, you can't call LWP::UserAgent's parameter methods, like
$ua->timeout();
as this won't be propagated to the POE component running the HTTP
requests. It might be added later. Currently, you have to add it to the
constructor, like
my $ua = LWP::UserAgent->new( timeout => 10 );
to take effect. LWP::UserAgent::POE translates the LWP::UserAgent
parameter names to POE::Component::Client::HTTP's parameters, which are
slightly different.
LEGALESE
Copyright 2008 by Mike Schilli and Rocco Caputo, all rights reserved.
This program is free software, you can redistribute it and/or modify it
under the same terms as Perl itself.
AUTHOR
The code of this module is based on Rocco Caputo's "pua-defer" code,
which has been included with his permission.
2008, Mike Schilli <cpan@perlmeister.com>