NAME
Blosxom::Header - Missing interface to modify HTTP headers
SYNOPSIS
use Blosxom::Header;
my $headers = { -type => 'text/html' };
my $h = Blosxom::Header->new($headers);
my $value = $h->get($key);
my $bool = $h->exists($key);
$h->set($key, $value); # overwrites existent header
$h->remove($key);
$h->{headers}; # same reference as $headers
DESCRIPTION
Blosxom, a weblog application, exports a global variable $header which is a reference to hash. This application passes $header CGI::header() to generate HTTP headers.
When plugin writers modify HTTP headers, they must write as follows:
package foo;
$blosxom::header->{'-type'} = 'text/plain';
It's obviously bad practice. Blosxom misses the interface to modify them.
This module allows you to modify them in an object-oriented way. If loaded, you might write as follows:
my $h = Blosxom::Header->new($blosxom::header);
$h->set('Content-Type' => 'text/plain');
METHODS
- $h = Blosxom::Header->new($headers);
-
Creates a new Blosxom::Header object. The object holds a reference to the original given $headers argument.
- $h->get('foo')
-
Returns a value of the specified HTTP header.
- $h->exists('foo')
-
Returns a Boolean value telling whether the specified HTTP header exists.
- $h->set('foo' => 'bar')
-
Sets a value of the specified HTTP header.
- $h->remove('foo')
-
Deletes the specified element from HTTP headers.
EXAMPLES
The following code is a Blosxom plugin to enable conditional GET and HEAD using If-None-Match
and If-Modified-Since
headers. Refer to Plack::Middleware::ConditionalGET.
plugins/conditional_get:
package conditional_get;
use strict;
use warnings;
use Blosxom::Header;
sub start { !$blosxom::static_entries }
sub last {
return unless $ENV{REQUEST_METHOD} =~ /^(GET|HEAD)$/;
my $h = Blosxom::Header->new($blosxom::header);
if (_etag_matches($h) or _not_modified_since($h)) {
$h->set('Status' => '304 Not Modified');
$h->remove($_)
for qw(Content-Type Content-Length Content-Disposition);
# Truncate output
$blosxom::output = q{};
}
return;
}
sub _etag_matches {
my $h = shift;
return unless $h->exists('ETag');
$h->get('ETag') eq _value($ENV{HTTP_IF_NONE_MATCH});
}
sub _not_modified_since {
my $h = shift;
return unless $h->exists('Last-Modified');
$h->exists('Last-Modified') eq _value($ENV{HTTP_IF_MODIFIED_SINCE});
}
sub _value {
my $str = shift;
$str =~ s{;.*$}{};
$str;
}
1;
DEPENDENCIES
SEE ALSO
The interface of this module is inspired by Plack::Util::headers.
AUTHOR
Ryo Anazawa (anazawa@cpan.org)
LICENSE AND COPYRIGHT
Copyright (c) 2011 Ryo Anazawa. All rights reserved.
This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See perlartistic.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.