LWP::Protocol(3pm) User Contributed Perl Documentation LWP::Protocol(3pm)NAMELWP::Protocol - Base class for LWP protocols
SYNOPSIS
package LWP::Protocol::foo;
use base qw(LWP::Protocol);
DESCRIPTION
This class is used as the base class for all protocol implementations
supported by the LWP library.
When creating an instance of this class using
"LWP::Protocol::create($url)", and you get an initialized subclass
appropriate for that access method. In other words, the "create" in
LWP::Protocol function calls the constructor for one of its subclasses.
All derived "LWP::Protocol" classes need to override the request()
method which is used to service a request. The overridden method can
make use of the collect() function to collect together chunks of data
as it is received.
METHODS
The following methods and functions are provided:
new
my $prot = LWP::Protocol->new();
The LWP::Protocol constructor is inherited by subclasses. As this is a
virtual base class this method should not be called directly.
create
my $prot = LWP::Protocol::create($scheme)
Create an object of the class implementing the protocol to handle the
given scheme. This is a function, not a method. It is more an object
factory than a constructor. This is the function user agents should use
to access protocols.
implementor
my $class = LWP::Protocol::implementor($scheme, [$class])
Get and/or set implementor class for a scheme. Returns '' if the
specified scheme is not supported.
request
$response = $protocol->request($request, $proxy, undef);
$response = $protocol->request($request, $proxy, '/tmp/sss');
$response = $protocol->request($request, $proxy, \&callback, 1024);
Dispatches a request over the protocol, and returns a response object.
This method needs to be overridden in subclasses. Refer to
LWP::UserAgent for description of the arguments.
collect
my $res = $prot->collect(undef, $response, $collector); # stored in $response
my $res = $prot->collect($filename, $response, $collector);
my $res = $prot->collect(sub { ... }, $response, $collector);
Collect the content of a request, and process it appropriately into a
scalar, file, or by calling a callback. If the first parameter is
undefined, then the content is stored within the $response. If it's a
simple scalar, then it's interpreted as a file name and the content is
written to this file. If it's a code reference, then content is passed
to this routine.
The collector is a routine that will be called and which is responsible
for returning pieces (as ref to scalar) of the content to process. The
$collector signals "EOF" by returning a reference to an empty string.
The return value is the HTTP::Response object reference.
Note: We will only use the callback or file argument if
"$response->is_success()". This avoids sending content data for
redirects and authentication responses to the callback which would be
confusing.
collect_once
$prot->collect_once($arg, $response, $content)
Can be called when the whole response content is available as content.
This will invoke "collect" in LWP::Protocol with a collector callback
that returns a reference to $content the first time and an empty string
the next.
SEE ALSO
Inspect the LWP/Protocol/file.pm and LWP/Protocol/http.pm files for
examples of usage.
COPYRIGHT
Copyright 1995-2001 Gisle Aas.
This library is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
perl v5.26.1 2017-12-26 LWP::Protocol(3pm)
