rss2html/lib/Rss2Html/Feed.pm

package Rss2Html::Feed;

=head1 Name 

Rss2Html::Feed - a feed

=head1 Description

This class represents a single feed. 

It currently has only one public method, update(), which updates the
feed.

=cut

use strict;
use warnings;
use v5.14;
use Moose;
use Try::Tiny;

use Cache::Memcached;
use Encode qw(decode_utf8);
use HTTP::Date;
use XML::Atom::Client;
use XML::RAI;

with 'MooseX::Log::Log4perl';

has 'id' => (
    is => 'rw',
);
has 'url' => (
    is => 'rw',
);
has 'active' => (
    is => 'rw',
);
has 'last_update' => (
    is => 'rw',
);
has 'title' => (
    is => 'rw',
);
has 'type' => (
    is => 'rw',
);
has 'allow_img' => (
    is => 'rw',
);
has 'expire' => (
    is => 'rw',
);

has 'dbh' => (
    is => 'rw',
);

my $mcd = Cache::Memcached->new(servers => ['127.0.0.1:11211']);


=head1 Methods

=cut

=head2 update

Update the feed. This is unconditional. The logic to decide which feeds
must be updated is in L<Rss2Html::FeedList::update_adaptive>.

=cut

sub update {
    my ($self) = @_;
    my $dbh = $self->dbh;

    my $now = int(time());

    if ($self->{type} eq 'rss') {
	local $@ = "unknown error";

        # XML::RAI has a parse_uri method, but we explicitely fetch the URI to get better diagnostics.
        # Probably should do this for atom, too, so we can autodetect the feed type.
        my $ua = LWP::UserAgent->new;
        $ua->agent("rss2html/1.0 (+http://www.hjp.at/projekte/rss2html/)");
        my $response = $ua->get($self->{url});
        if ($response->code != 200) {
            $self->log->warn("GET $self->{url} failed: " . $response->status_line);
            return;
        }
        $self->log->info("$self->{url} has content type " . $response->content_type);

	my $rai = eval {XML::RAI->parse_string($response->content) };
	if ($rai) {
	    $rai->time_format('EPOCH');
	    if ($rai->channel->title ne $self->{title}) {
		$self->log->info("set title");
		$dbh->do("update feeds set title=? where id=?", {},
			 $rai->channel->title, $self->{id});
	    }
	    $self->log->info("checking " . scalar(@{$rai->items}) . " items in db");
	    for my $item ( @{$rai->items} ) {
		my $item_db = $dbh->selectrow_hashref("select * from items where link=?", {}, $item->link);
		if ($item_db) {
		    $self->log->info("item $item_db->{id} seen");
		    $dbh->do("update items set seen=? where id=?", {}, $now, $item_db->{id});
		} else {
		    $self->log->info("new");

		    my $issued = $item->issued // $now;
                    if ($issued < $self->{last_update} || $issued > $now) {
                        # $issued is clearly wrong. Could be any time between $self->{last_update} and $now.
                        # Choose a random time in the interval.
                        my $guess_issued = $self->{last_update} + int(rand($now - $self->{last_update}));
                        $self->log->info("fixing up issued time: $issued -> $guess_issued");
                        $issued = $guess_issued;
                    }

		    $self->log->info("item " . $item->link . " new");
		    $dbh->do("insert into items(title, link, content, issued, seen, feed_id) values(?, ?, ?, ?, ?, ?)",
			     {},
			     $item->title, $item->link, $item->content, $issued, $now, $self->{id}
			  );
		    $self->invalidate_item_info;
		}
	    }
	} else {
	    $self->log->error("error getting $self->{url}: $@");
	}
    } elsif ($self->{type} eq 'atom') {
	my $api = XML::Atom::Client->new();
        my $atomfeed;
        try {
            # This doesn't work. XML::Atom::Client EXITS on error!
            $atomfeed = $api->getFeed($self->{url});
        } catch {
            $self->log->error("error fetching $self->{url}: $@");
        }
	if ($atomfeed) {
	    my @items = $atomfeed->entries;
	    for my $item (@items) {
		my $link = $self->atom_main_link($item);
		my $item_db = $dbh->selectrow_hashref("select * from items where link=?", {}, $link);
		if ($item_db) {
		    $self->log->info("item $item_db->{id} seen");
		    $dbh->do("update items set seen=? where id=?", {}, $now, $item_db->{id});
		} else {
		    $self->log->info("new");
		    my $title = decode_utf8($item->title); # XXX - Workaround?
		    my $content = $item->content;
                    my $summary = $item->summary;
		    my $body = $content          ? $content->body        :
                               defined($summary) ? decode_utf8($summary) : undef;

		    $self->log->info("item " . $link . " new");

                    my $issued = str2time($item->updated) // $now;
                    if ($issued < $self->{last_update} || $issued > $now) {
                        # $issued is clearly wrong. Could be any time between $self->{last_update} and $now.
                        # Choose a random time in the interval.
                        my $guess_issued = $self->{last_update} + int(rand($now - $self->{last_update}));
                        $self->log->info("fixing up issued time: $issued -> $guess_issued");
                        $issued = $guess_issued;
                    }

		    $dbh->do("insert into items(title, link, content, issued, seen, feed_id) values(?, ?, ?, ?, ?, ?)",
			     {},
			     $title, $link, $body, $issued, $now, $self->{id}
			  );
		    $self->invalidate_item_info;
		}
	    }
	}
    } else {
	$self->log->info("ignoring feed type $self->{type} of feed #$self->{id}: $self->{title}");
        return;
    }

    $dbh->do("update feeds set last_update=? where id=?", {}, $now, $self->{id});
}


sub atom_main_link {
    my ($self, $item) = @_; # XXX should probably be a method of $item
    for my $link ($item->link) {
        # workaround for https://github.com/miyagawa/xml-atom/issues/16
        my $href = $link->href // $link->elem->getAttributeNS('http://www.w3.org/2005/Atom', 'href');
        my $rel = $link->rel // $link->elem->getAttributeNS('http://www.w3.org/2005/Atom', 'rel');
        my $type = $link->type // $link->elem->getAttributeNS('http://www.w3.org/2005/Atom', 'type');

        if (!$href) {
            $self->log->warn("href undefined, skip");
            next;
        }
        $self->log->info("checking href ", $href, "\n");
        if (defined $rel && $rel ne 'alternate') {
            $self->log->info("rel ", $rel, " unexpected, skip");
            next;
        }
        if (defined $type && $type ne 'text/html') {
            $self->log->info("type ", $type, " unexpected, skip\n");
            next;
        }
        $self->log->info("match!\n");
        return $href;
    }
}

sub invalidate_item_info {
    my ($self) = @_;

    my $dbh = $self->dbh;
    my $users = $dbh->selectcol_arrayref("select distinct username from read");
    for my $user (@$users) {
	$mcd->delete($self->item_info_key($user));
    }
}

sub item_info_key {
    my ($self, $user) = @_;
    return "rss2html/item_info/" . $user . "/" . $self->id;
}

#---
__PACKAGE__->meta->make_immutable;
1;

# vim: tw=132