# $Id: Feed.pm 4536 2004-05-11 05:33:05Z btrott $package XML::Atom::Feed;use strict;use XML::Atom;use base qw( XML::Atom::Thing );use XML::Atom::Entry;BEGIN {    if (LIBXML) {        *entries = \&entries_libxml;        *add_entry = \&add_entry_libxml;    } else {        *entries = \&entries_xpath;        *add_entry = \&add_entry_xpath;    }}use constant NS => 'http://purl.org/atom/ns#';sub init {    my $atom = shift;    my %param = @_ == 1 ? (Stream => $_[0]) : @_;    if (UNIVERSAL::isa($param{Stream}, 'URI')) {        my @feeds = __PACKAGE__->find_feeds($param{Stream});        return $atom->error("Can't find Atom file") unless @feeds;        my $ua = LWP::UserAgent->new;        my $req = HTTP::Request->new(GET => $feeds[0]);        my $res = $ua->request($req);        if ($res->is_success) {            $param{Stream} = \$res->content;        }    }    $atom->SUPER::init(%param);}sub find_feeds {    my $class = shift;    my($uri) = @_;    my $ua = LWP::UserAgent->new;    my $req = HTTP::Request->new(GET => $uri);    my $res = $ua->request($req);    return unless $res->is_success;    my @feeds;    if ($res->content_type eq 'text/html' || $res->content_type eq 'application/xhtml+xml') {        my $base_uri = $uri;        my $find_links = sub {            my($tag, $attr) = @_;            if ($tag eq 'link') {                return unless $attr->{rel};                my %rel = map { $_ => 1 } split /\s+/, lc($attr->{rel});                (my $type = lc $attr->{type}) =~ s/^\s*//;                $type =~ s/\s*$//;                push @feeds, URI->new_abs($attr->{href}, $base_uri)->as_string                   if $rel{alternate} &&                      $type eq 'application/atom+xml';            } elsif ($tag eq 'base') {                $base_uri = $attr->{href};            }        };        require HTML::Parser;        my $p = HTML::Parser->new(api_version => 3,                                  start_h => [ $find_links, "tagname, attr" ]);        $p->parse($res->content);    } else {        @feeds = ($uri);    }    @feeds;}sub element_name { 'feed' }sub entries_libxml {    my $feed = shift;    my @res = $feed->{doc}->getElementsByTagNameNS(NS, 'entry') or return;    my @entries;    for my $res (@res) {        my $entry = XML::Atom::Entry->new(Elem => $res->cloneNode(1));        push @entries, $entry;    }    @entries;}sub entries_xpath {    my $feed = shift;    my $set = $feed->{doc}->find("descendant-or-self::*[local-name()='entry' and namespace-uri()='" . NS . "']");    my @entries;    for my $elem ($set->get_nodelist) {        ## Delete the link to the parent (feed) element, and append        ## the default Atom namespace.        $elem->del_parent_link;        my $ns = XML::XPath::Node::Namespace->new('#default' => NS);        $elem->appendNamespace($ns);        my $entry = XML::Atom::Entry->new(Elem => $elem);        push @entries, $entry;    }    @entries;}sub add_entry_libxml {    my $feed = shift;    my($entry) = @_;    $feed->{doc}->getDocumentElement->appendChild($entry->{doc}->getDocumentElement);}sub add_entry_xpath {    my $feed = shift;    my($entry) = @_;    $feed->{doc}->appendChild($entry->{doc});}1;__END__=head1 NAMEXML::Atom::Feed - Atom feed=head1 SYNOPSIS    use XML::Atom::Feed;    use XML::Atom::Entry;    my $feed = XML::Atom::Feed->new;    $feed->title('My Weblog');    my $entry = XML::Atom::Entry->new;    $entry->title('First Post');    $entry->content('Post Body');    $feed->add_entry($entry);    my @entries = $feed->entries;    my $xml = $feed->as_xml;    ## Get a list of the <link rel="..." /> tags in the feed.    my $links = $feed->link;    ## Find all of the Atom feeds on a given page, using auto-discovery.    my @uris = XML::Atom::Feed->find_feeds('http://www.example.com/');    ## Use auto-discovery to load the first Atom feed on a given page.    my $feed = XML::Atom::Feed->new(URI->new('http://www.example.com/'));=head1 USAGE=head2 XML::Atom::Feed->new([ $stream ])Creates a new feed object, and if I<$stream> is supplied, fills it with thedata specified by I<$stream>.Automatically handles autodiscovery if I<$stream> is a URI (see below).Returns the new I<XML::Atom::Feed> object. On failure, returns C<undef>.I<$stream> can be any one of the following:=over 4=item * Reference to a scalarThis is treated as the XML body of the feed.=item * ScalarThis is treated as the name of a file containing the feed XML.=item * FilehandleThis is treated as an open filehandle from which the feed XML can be read.=item * URI objectThis is treated as a URI, and the feed XML will be retrieved from the URI.If the content type returned from fetching the content at URI isI<text/html>, this method will automatically try to perform auto-discoveryby looking for a I<E<lt>linkE<gt>> tag describing the feed URL. If sucha URL is found, the feed XML will be automatically retrieved.If the URI is already of a feed, no auto-discovery is necessary, and thefeed XML will be retrieved and parsed as normal.=back=head2 XML::Atom::Feed->find_feeds($uri)Given a URI I<$uri>, use auto-discovery to find all of the Atom feeds linkedfrom that page (using I<E<lt>linkE<gt>> tags).Returns a list of feed URIs. =head2 $feed->linkIf called in scalar context, returns an I<XML::Atom::Link> objectcorresponding to the first I<E<lt>linkE<gt>> tag found in the feed.If called in list context, returns a list of I<XML::Atom::Link> objectscorresponding to all of the I<E<lt>linkE<gt>> tags found in the feed.=head2 $feed->add_link($link)Adds the link I<$link>, which must be an I<XML::Atom::Link> object, tothe feed as a new I<E<lt>linkE<gt>> tag. For example:    my $link = XML::Atom::Link->new;    $link->type('text/html');    $link->rel('alternate');    $link->href('http://www.example.com/');    $feed->add_link($link);=head1 AUTHOR & COPYRIGHTPlease see the I<XML::Atom> manpage for author, copyright, and licenseinformation.=cut