XML::Feed(3) Syndication feed parser and auto-discovery

SYNOPSIS


use XML::Feed;
my $feed = XML::Feed->parse(URI->new('http://example.com/atom.xml'))
or die XML::Feed->errstr;
print $feed->title, "\n";
for my $entry ($feed->entries) {
}
## Find all of the syndication feeds on a given page, using
## auto-discovery.
my @feeds = XML::Feed->find_feeds('http://example.com/');

DESCRIPTION

XML::Feed is a syndication feed parser for both RSS and Atom feeds. It also implements feed auto-discovery for finding feeds, given a URI.

XML::Feed supports the following syndication feed formats:

  • RSS 0.91
  • RSS 1.0
  • RSS 2.0
  • Atom

The goal of XML::Feed is to provide a unified API for parsing and using the various syndication formats. The different flavors of RSS and Atom handle data in different ways: date handling; summaries and content; escaping and quoting; etc. This module attempts to remove those differences by providing a wrapper around the formats and the classes implementing those formats (XML::RSS and XML::Atom::Feed). For example, dates are handled differently in each of the above formats. To provide a unified API for date handling, XML::Feed converts all date formats transparently into DateTime objects, which it then returns to the caller.

USAGE

XML::Feed->new($format)

Creates a new empty XML::Feed object using the format $format.

    $feed = XML::Feed->new('Atom');
    $feed = XML::Feed->new('RSS');
    $feed = XML::Feed->new('RSS', version => '0.91');

XML::Feed->parse($stream)

XML::Feed->parse($stream, $format)

Parses a syndication feed identified by $stream and returns an XML::Feed object. $stream can be any one of the following:
  • Scalar reference

    A reference to string containing the XML body of the feed.

  • Filehandle

    An open filehandle from which the feed XML will be read.

  • File name

    The name of a file containing the feed XML.

  • URI object

    A URI from which the feed XML will be retrieved.

$format allows you to override format guessing.

XML::Feed->find_feeds($uri)

Given a URI $uri, use auto-discovery to find all of the feeds linked from that page (using <link> tags).

Returns a list of feed URIs.

XML::Feed->identify_format(\$xml)

Given the xml of a feed return what format it is in, with "Atom" or "RSS" for all versions of RSS. Note that you pass in a scalar ref to the xml string.

$feed->convert($format)

Converts the XML::Feed object into the $format format, and returns the new object.

$feed->splice($other_feed)

Splices in all of the entries from the feed $other_feed into $feed, skipping posts that are already in $feed.

$feed->format

Returns the format of the feed ("Atom", or some version of "RSS").

$feed->title([ $title ])

The title of the feed/channel.

$feed->base([ $base ])

The url base of the feed/channel.

$feed->link([ $uri ])

The permalink of the feed/channel.

$feed->tagline([ $tagline ])

The description or tagline of the feed/channel.

$feed->description([ $description ])

Alias for $feed->tagline.

$feed->author([ $author ])

The author of the feed/channel.

$feed->language([ $language ])

The language of the feed.

$feed->copyright([ $copyright ])

The copyright notice of the feed.

$feed->modified([ $modified ])

A DateTime object representing the last-modified date of the feed.

If present, $modified should be a DateTime object.

$feed->generator([ $generator ])

The generator of the feed.

$feed->self_link ([ $uri ])

The Atom Self-link of the feed:

<http://validator.w3.org/feed/docs/warning/MissingAtomSelfLink.html>

A string.

$feed->entries

A list of the entries/items in the feed. Returns an array containing XML::Feed::Entry objects.

$feed->items

A synonym (alias) for <$feed->entries>.

$feed->add_entry($entry)

Adds an entry to the feed. $entry should be an XML::Feed::Entry object in the correct format for the feed.

$feed->as_xml

Returns an XML representation of the feed, in the format determined by the current format of the $feed object.

$feed->first_link ([ $uri ])

The Atom First-link for feed paging and archiving (RFC 5005).

<http://tools.ietf.org/html/rfc5005>

$feed->last_link ([ $uri ])

The Atom Last-link for feed paging and archiving.

$feed->next_link ([ $uri ])

The Atom Next-link for feed paging and archiving.

$feed->previous_link ([ $uri ])

The Atom Previous-link for feed paging and archiving.

$feed->current_link ([ $uri ])

The Atom Current-link for feed paging and archiving.

$feed->next_archive_link ([ $uri ])

The Atom Next-link for feed paging and archiving.

$feed->prev_archive_link ([ $uri ])

The Atom Prev-Archive-link for feed paging and archiving.

PACKAGE VARIABLES

$XML::Feed::Format::RSS::PREFERRED_PARSER
If you want to use another RSS parser class than XML::RSS (default), you can change the class by setting $PREFERRED_PARSER variable in the XML::Feed::Format::RSS package.

    $XML::Feed::Format::RSS::PREFERRED_PARSER = "XML::RSS::LibXML";

Note: this will only work for parsing feeds, not creating feeds.

Note: Only "XML::RSS::LibXML" version 0.3004 is known to work at the moment.

$XML::Feed::MULTIPLE_ENCLOSURES
Although the RSS specification states that there can be at most one enclosure per item some feeds break this rule.

If this variable is set then "XML::Feed" captures all of them and makes them available as a list.

Otherwise it returns the last enclosure parsed.

Note: "XML::RSS" version 1.44 is needed for this to work.

VALID FEEDS

For reference, this cgi script will create valid, albeit nonsensical feeds (according to "http://feedvalidator.org" anyway) for Atom 1.0 and RSS 0.90, 0.91, 1.0 and 2.0.

    #!perl -w
    use strict;
    use CGI;
    use CGI::Carp qw(fatalsToBrowser);
    use DateTime;
    use XML::Feed;
    my $cgi  = CGI->new;
    my @args = ( $cgi->param('format') || "Atom" );
    push @args, ( version => $cgi->param('version') ) if $cgi->param('version');
    my $feed = XML::Feed->new(@args);
    $feed->id("http://".time.rand()."/");
    $feed->title('Test Feed');
    $feed->link($cgi->url);
    $feed->self_link($cgi->url( -query => 1, -full => 1, -rewrite => 1) );
    $feed->modified(DateTime->now);
    my $entry = XML::Feed::Entry->new();
    $entry->id("http://".time.rand()."/");
    $entry->link("http://example.com");
    $entry->title("Test entry");
    $entry->summary("Test summary");
    $entry->content("Foo");
    $entry->modified(DateTime->now);
    $entry->author('[email protected] (Testy McTesterson)');
    $feed->add_entry($entry);
    my $mime = ("Atom" eq $feed->format) ? "application/atom+xml" : "application/rss+xml";
    print $cgi->header($mime);
    print $feed->as_xml;

LICENSE

XML::Feed is free software; you may redistribute it and/or modify it under the same terms as Perl itself.

AUTHOR & COPYRIGHT

Except where otherwise noted, XML::Feed is Copyright 2004-2008 Six Apart. All rights reserved.

SUPPORT

For support contact the XML::Feed mailing list - [email protected].

SOURCE CODE

The latest version of XML::Feed can be found at

    http://github.com/davorg/XML-Feed