FM / LWP

/usr/local/share/perl5/LWP

Name	Size	Mode	Actions
Authen/	-	0755	rm
Protocol/	-	0755	rm
ConnCache.pm	7621	0444	edit dl rm
Debug.pm	2573	0444	edit dl rm
DebugFile.pm	43	0444	edit dl rm
MemberMixin.pm	846	0444	edit dl rm
Protocol.pm	7915	0444	edit dl rm
RobotUA.pm	7713	0444	edit dl rm
Simple.pm	6326	0444	edit dl rm
UserAgent.pm	59802	0444	edit dl rm

Edit: /usr/local/share/perl5/LWP/Protocol.pm (7915B)

package LWP::Protocol;

require LWP::MemberMixin;
@ISA = qw(LWP::MemberMixin);
$VERSION = "6.15";

use strict;
use Carp ();
use HTTP::Status ();
use HTTP::Response;

my %ImplementedBy = (); # scheme => classname

sub new
{
    my($class, $scheme, $ua) = @_;

my $self = bless {
	scheme => $scheme,
	ua => $ua,

# historical/redundant
        max_size => $ua->{max_size},
    }, $class;

$self;
}

sub create
{
    my($scheme, $ua) = @_;
    my $impclass = LWP::Protocol::implementor($scheme) or
	Carp::croak("Protocol scheme '$scheme' is not supported");

# hand-off to scheme specific implementation sub-class
    my $protocol = $impclass->new($scheme, $ua);

return $protocol;
}

sub implementor
{
    my($scheme, $impclass) = @_;

if ($impclass) {
	$ImplementedBy{$scheme} = $impclass;
    }
    my $ic = $ImplementedBy{$scheme};
    return $ic if $ic;

return '' unless $scheme =~ /^([.+\-\w]+)$/;  # check valid URL schemes
    $scheme = $1; # untaint
    $scheme =~ s/[.+\-]/_/g;  # make it a legal module name

# scheme not yet known, look for a 'use'd implementation
    $ic = "LWP::Protocol::$scheme";  # default location
    $ic = "LWP::Protocol::nntp" if $scheme eq 'news'; #XXX ugly hack
    no strict 'refs';
    # check we actually have one for the scheme:
    unless (@{"${ic}::ISA"}) {
	# try to autoload it
	eval "require $ic";
	if ($@) {
	    if ($@ =~ /Can't locate/) { #' #emacs get confused by '
		$ic = '';
	    }
	    else {
		die "$@\n";
	    }
	}
    }
    $ImplementedBy{$scheme} = $ic if $ic;
    $ic;
}

sub request
{
    my($self, $request, $proxy, $arg, $size, $timeout) = @_;
    Carp::croak('LWP::Protocol::request() needs to be overridden in subclasses');
}

# legacy
sub timeout    { shift->_elem('timeout',    @_); }
sub max_size   { shift->_elem('max_size',   @_); }

sub collect
{
    my ($self, $arg, $response, $collector) = @_;
    my $content;
    my($ua, $max_size) = @{$self}{qw(ua max_size)};

eval {
	local $\; # protect the print below from surprises
        if (!defined($arg) || !$response->is_success) {
            $response->{default_add_content} = 1;
        }
        elsif (!ref($arg) && length($arg)) {
            open(my $fh, ">", $arg) or die "Can't write to '$arg': $!";
	    binmode($fh);
            push(@{$response->{handlers}{response_data}}, {
                callback => sub {
                    print $fh $_[3] or die "Can't write to '$arg': $!";
                    1;
                },
            });
            push(@{$response->{handlers}{response_done}}, {
                callback => sub {
		    close($fh) or die "Can't write to '$arg': $!";
		    undef($fh);
		},
	    });
        }
        elsif (ref($arg) eq 'CODE') {
            push(@{$response->{handlers}{response_data}}, {
                callback => sub {
		    &$arg($_[3], $_[0], $self);
		    1;
                },
            });
        }
        else {
            die "Unexpected collect argument '$arg'";
        }

$ua->run_handlers("response_header", $response);

if (delete $response->{default_add_content}) {
            push(@{$response->{handlers}{response_data}}, {
		callback => sub {
		    $_[0]->add_content($_[3]);
		    1;
		},
	    });
        }

my $content_size = 0;
        my $length = $response->content_length;
        my %skip_h;

while ($content = &$collector, length $$content) {
            for my $h ($ua->handlers("response_data", $response)) {
                next if $skip_h{$h};
                unless ($h->{callback}->($response, $ua, $h, $$content)) {
                    # XXX remove from $response->{handlers}{response_data} if present
                    $skip_h{$h}++;
                }
            }
            $content_size += length($$content);
            $ua->progress(($length ? ($content_size / $length) : "tick"), $response);
            if (defined($max_size) && $content_size > $max_size) {
                $response->push_header("Client-Aborted", "max_size");
                last;
            }
        }
    };
    my $err = $@;
    delete $response->{handlers}{response_data};
    delete $response->{handlers} unless %{$response->{handlers}};
    if ($err) {
        chomp($err);
        $response->push_header('X-Died' => $err);
        $response->push_header("Client-Aborted", "die");
        return $response;
    }

return $response;
}

sub collect_once
{
    my($self, $arg, $response) = @_;
    my $content = \ $_[3];
    my $first = 1;
    $self->collect($arg, $response, sub {
	return $content if $first--;
	return \ "";
    });
}

__END__

=head1 NAME

LWP::Protocol - Base class for LWP protocols

=head1 SYNOPSIS

package LWP::Protocol::foo;
 require LWP::Protocol;
 @ISA=qw(LWP::Protocol);

=head1 DESCRIPTION

This class is used a the base class for all protocol implementations
supported by the LWP library.

When creating an instance of this class using
C<LWP::Protocol::create($url)>, and you get an initialized subclass
appropriate for that access method. In other words, the
LWP::Protocol::create() 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.

The following methods and functions are provided:

=over 4

=item $prot = LWP::Protocol->new()

The LWP::Protocol constructor is inherited by subclasses. As this is a
virtual base class this method should B<not> be called directly.

=item $prot = LWP::Protocol::create($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.

=item $class = LWP::Protocol::implementor($scheme, [$class])

Get and/or set implementor class for a scheme.  Returns '' if the
specified scheme is not supported.

=item $prot->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
L<LWP::UserAgent> for description of the arguments.

=item $prot->collect($arg, $response, $collector)

Called to collect the content of a request, and process it
appropriately into a scalar, file, or by calling a callback.  If $arg
is undefined, then the content is stored within the $response.  If
$arg is a simple scalar, then $arg is interpreted as a file name and
the content is written to this file.  If $arg is a reference to a
routine, 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 from collect() is the $response object reference.

B<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.

=item $prot->collect_once($arg, $response, $content)

Can be called when the whole response content is available as
$content.  This will invoke collect() with a collector callback that
returns a reference to $content the first time and an empty string the
next.

=back

=head1 SEE ALSO

Inspect the F<LWP/Protocol/file.pm> and F<LWP/Protocol/http.pm> files
for examples of usage.

=head1 COPYRIGHT

This library is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.

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