path: root/IkiWiki/Plugin/aggregate.pm

#!/usr/bin/perl
# Blog aggregation plugin.
package IkiWiki::Plugin::aggregate;

use warnings;
use strict;
use IkiWiki 2.00;
use HTML::Parser;
use HTML::Tagset;
use HTML::Entities;
use URI;
use open qw{:utf8 :std};

my %feeds;
my %guids;

sub import { #{{{
    hook(type => "getopt", id => "aggregate", call => \&getopt);
    hook(type => "checkconfig", id => "aggregate", call => \&checkconfig);
    hook(type => "needsbuild", id => "aggregate", call => \&needsbuild);
    hook(type => "preprocess", id => "aggregate", call => \&preprocess);
        hook(type => "delete", id => "aggregate", call => \&delete);
    hook(type => "savestate", id => "aggregate", call => \&savestate);
} # }}}

sub getopt () { #{{{
        eval q{use Getopt::Long};
    error($@) if $@;
        Getopt::Long::Configure('pass_through');
        GetOptions("aggregate" => \$config{aggregate});
} #}}}

sub checkconfig () { #{{{
    if ($config{aggregate} && ! ($config{post_commit} && 
                                 IkiWiki::commit_hook_enabled())) {
        # See if any feeds need aggregation.
        loadstate();
        my @feeds=needsaggregate();
        return unless @feeds;
        if (! lockaggregate()) {
            debug("an aggregation process is already running");
            return;
        }
        # force a later rebuild of source pages
        $IkiWiki::forcerebuild{$_->{sourcepage}}=1
            foreach @feeds;

        # Fork a child process to handle the aggregation.
        # The parent process will then handle building the
        # result. This avoids messy code to clear state
        # accumulated while aggregating.
        defined(my $pid = fork) or error("Can't fork: $!");
        if (! $pid) {
            IkiWiki::loadindex();

            # Aggregation happens without the main wiki lock
            # being held. This allows editing pages etc while
            # aggregation is running.
            aggregate(@feeds);

            IkiWiki::lockwiki;
            # Merge changes, since aggregation state may have
            # changed on disk while the aggregation was happening.
            mergestate();
            expire();
            savestate();
            IkiWiki::unlockwiki;
            exit 0;
        }
        waitpid($pid,0);
        if ($?) {
            error "aggregation failed with code $?";
        }

        clearstate();
        unlockaggregate();
    }
} #}}}

sub needsbuild (@) { #{{{
    my $needsbuild=shift;
    
    loadstate();

    foreach my $feed (values %feeds) {
        if (exists $pagesources{$feed->{sourcepage}} && 
            grep { $_ eq $pagesources{$feed->{sourcepage}} } @$needsbuild) {
            # Mark all feeds originating on this page as 
            # not yet seen; preprocess will unmark those that
            # still exist.
            markunseen($feed->{sourcepage});
        }
    }
} # }}}

sub preprocess (@) { #{{{
    my %params=@_;

    foreach my $required (qw{name url}) {
        if (! exists $params{$required}) {
            return "[[aggregate ".sprintf(gettext("missing %s parameter"), $required)."]]";
        }
    }

    my $feed={};
    my $name=$params{name};
    if (exists $feeds{$name}) {
        $feed=$feeds{$name};
    }
    else {
        $feeds{$name}=$feed;
    }
    $feed->{name}=$name;
    $feed->{sourcepage}=$params{page};
    $feed->{url}=$params{url};
    my $dir=exists $params{dir} ? $params{dir} : $params{page}."/".IkiWiki::titlepage($params{name});
    $dir=~s/^\/+//;
    ($dir)=$dir=~/$config{wiki_file_regexp}/;
    $feed->{dir}=$dir;
    $feed->{feedurl}=defined $params{feedurl} ? $params{feedurl} : "";
    $feed->{updateinterval}=defined $params{updateinterval} ? $params{updateinterval} * 60 : 15 * 60;
    $feed->{expireage}=defined $params{expireage} ? $params{expireage} : 0;
    $feed->{expirecount}=defined $params{expirecount} ? $params{expirecount} : 0;
    delete $feed->{unseen};
    $feed->{lastupdate}=0 unless defined $feed->{lastupdate};
    $feed->{numposts}=0 unless defined $feed->{numposts};
    $feed->{newposts}=0 unless defined $feed->{newposts};
    $feed->{message}=gettext("new feed") unless defined $feed->{message};
    $feed->{error}=0 unless defined $feed->{error};
    $feed->{tags}=[];
    while (@_) {
        my $key=shift;
        my $value=shift;
        if ($key eq 'tag') {
            push @{$feed->{tags}}, $value;
        }
    }

    return "<a href=\"".$feed->{url}."\">".$feed->{name}."</a>: ".
           ($feed->{error} ? "<em>" : "").$feed->{message}.
           ($feed->{error} ? "</em>" : "").
           " (".$feed->{numposts}." ".gettext("posts").
           ($feed->{newposts} ? "; ".$feed->{newposts}.
                                " ".gettext("new") : "").
           ")";
} # }}}

sub delete (@) { #{{{
    my @files=@_;

    # Remove feed data for removed pages.
    foreach my $file (@files) {
        my $page=pagename($file);
        markunseen($page);
    }
} #}}}

sub markunseen ($) { #{{{
    my $page=shift;

    foreach my $id (keys %feeds) {
        if ($feeds{$id}->{sourcepage} eq $page) {
            $feeds{$id}->{unseen}=1;
        }
    }
} #}}}

my $state_loaded=0;

sub loadstate () { #{{{
    return if $state_loaded;
    $state_loaded=1;
    if (-e "$config{wikistatedir}/aggregate") {
        open(IN, "$config{wikistatedir}/aggregate") ||
            die "$config{wikistatedir}/aggregate: $!";
        while (<IN>) {
            $_=IkiWiki::possibly_foolish_untaint($_);
            chomp;
            my $data={};
            foreach my $i (split(/ /, $_)) {
                my ($field, $val)=split(/=/, $i, 2);
                if ($field eq "name" || $field eq "feed" ||
                    $field eq "guid" || $field eq "message") {
                    $data->{$field}=decode_entities($val, " \t\n");
                }
                elsif ($field eq "tag") {
                    push @{$data->{tags}}, $val;
                }
                else {
                    $data->{$field}=$val;
                }
            }
            
            if (exists $data->{name}) {
                $feeds{$data->{name}}=$data;
            }
            elsif (exists $data->{guid}) {
                $guids{$data->{guid}}=$data;
            }
        }

        close IN;
    }
} #}}}

sub savestate () { #{{{
    return unless $state_loaded;
    garbage_collect();
    my $newfile="$config{wikistatedir}/aggregate.new";
    my $cleanup = sub { unlink($newfile) };
    open (OUT, ">$newfile") || error("open $newfile: $!", $cleanup);
    foreach my $data (values %feeds, values %guids) {
        my @line;
        foreach my $field (keys %$data) {
            if ($field eq "name" || $field eq "feed" ||
                $field eq "guid" || $field eq "message") {
                push @line, "$field=".encode_entities($data->{$field}, " \t\n");
            }
            elsif ($field eq "tags") {
                push @line, "tag=$_" foreach @{$data->{tags}};
            }
            else {
                push @line, "$field=".$data->{$field};
            }
        }
        print OUT join(" ", @line)."\n" || error("write $newfile: $!", $cleanup);
    }
    close OUT || error("save $newfile: $!", $cleanup);
    rename($newfile, "$config{wikistatedir}/aggregate") ||
        error("rename $newfile: $!", $cleanup);
} #}}}

sub garbage_collect () { #{{{
    foreach my $name (keys %feeds) {
        # remove any feeds that were not seen while building the pages
        # that used to contain them
        if ($feeds{$name}->{unseen}) {
            delete $feeds{$name};
        }
    }

    foreach my $guid (values %guids) {
        # any guid whose feed is gone should be removed
        if (! exists $feeds{$guid->{feed}}) {
            unlink pagefile($guid->{page})
                if exists $guid->{page};
            delete $guids{$guid->{guid}};
        }
        # handle expired guids
        elsif ($guid->{expired} && exists $guid->{page}) {
            unlink pagefile($guid->{page});
            delete $guid->{page};
            delete $guid->{md5};
        }
    }
} #}}}

sub mergestate () { #{{{
    # Load the current state in from disk, and merge into it
    # values from the state in memory that might have changed
    # during aggregation.
    my %myfeeds=%feeds;
    my %myguids=%guids;
    clearstate();
    loadstate();

    # All that can change in feed state during aggregation is a few
    # fields.
    foreach my $name (keys %myfeeds) {
        if (exists $feeds{$name}) {
            foreach my $field (qw{message lastupdate numposts
                                  newposts error}) {
                $feeds{$name}->{$field}=$myfeeds{$name}->{$field};
            }
        }
    }

    # New guids can be created during aggregation.
    # It's also possible that guids were removed from the on-disk state
    # while the aggregation was in process. That would only happen if
    # their feed was also removed, so any removed guids added back here
    # will be garbage collected later.
    foreach my $guid (keys %myguids) {
        if (! exists $guids{$guid}) {
            $guids{$guid}=$myguids{$guid};
        }
    }
} #}}}

sub clearstate () { #{{{
    %feeds=();
    %guids=();
    $state_loaded=0;
} #}}}

sub expire () { #{{{
    foreach my $feed (values %feeds) {
        next unless $feed->{expireage} || $feed->{expirecount};
        my $count=0;
        my %seen;
        foreach my $item (sort { $IkiWiki::pagectime{$b->{page}} <=> $IkiWiki::pagectime{$a->{page}} }
                          grep { exists $_->{page} && $_->{feed} eq $feed->{name} && $IkiWiki::pagectime{$_->{page}} }
                          values %guids) {
            if ($feed->{expireage}) {
                my $days_old = (time - $IkiWiki::pagectime{$item->{page}}) / 60 / 60 / 24;
                if ($days_old > $feed->{expireage}) {
                    debug(sprintf(gettext("expiring %s (%s days old)"),
                        $item->{page}, int($days_old)));
                    $item->{expired}=1;
                }
            }
            elsif ($feed->{expirecount} &&
                   $count >= $feed->{expirecount}) {
                debug(sprintf(gettext("expiring %s"), $item->{page}));
                $item->{expired}=1;
            }
            else {
                if (! $seen{$item->{page}}) {
                    $seen{$item->{page}}=1;
                    $count++;
                }
            }
        }
    }
} #}}}

sub needsaggregate () { #{{{
    return values %feeds if $config{rebuild};
    return grep { time - $_->{lastupdate} >= $_->{updateinterval} } values %feeds;
} #}}}

sub aggregate (@) { #{{{
    eval q{use XML::Feed};
    error($@) if $@;
    eval q{use URI::Fetch};
    error($@) if $@;

    foreach my $feed (@_) {
        $feed->{lastupdate}=time;
        $feed->{newposts}=0;
        $feed->{message}=sprintf(gettext("processed ok at %s"),
            displaytime($feed->{lastupdate}));
        $feed->{error}=0;

        debug(sprintf(gettext("checking feed %s ..."), $feed->{name}));

        if (! length $feed->{feedurl}) {
            my @urls=XML::Feed->find_feeds($feed->{url});
            if (! @urls) {
                $feed->{message}=sprintf(gettext("could not find feed at %s"), $feed->{url});
                $feed->{error}=1;
                debug($feed->{message});
                next;
            }
            $feed->{feedurl}=pop @urls;
        }
        my $res=URI::Fetch->fetch($feed->{feedurl});
        if (! $res) {
            $feed->{message}=URI::Fetch->errstr;
            $feed->{error}=1;
            debug($feed->{message});
            next;
        }
        if ($res->status == URI::Fetch::URI_GONE()) {
            $feed->{message}=gettext("feed not found");
            $feed->{error}=1;
            debug($feed->{message});
            next;
        }
        my $content=$res->content;
        my $f=eval{XML::Feed->parse(\$content)};
        if ($@) {
            # One common cause of XML::Feed crashing is a feed
            # that contains invalid UTF-8 sequences. Convert
            # feed to ascii to try to work around.
            $feed->{message}.=" ".sprintf(gettext("(invalid UTF-8 stripped from feed)"));
            $content=Encode::decode_utf8($content);
            $f=eval{XML::Feed->parse(\$content)};
        }
        if ($@) {
            # Another possibility is badly escaped entities.
            $feed->{message}.=" ".sprintf(gettext("(feed entities escaped)"));
            $content=~s/\&(?!amp)(\w+);/&amp;$1;/g;
            $content=Encode::decode_utf8($content);
            $f=eval{XML::Feed->parse(\$content)};
        }
        if ($@) {
            $feed->{message}=gettext("feed crashed XML::Feed!")." ($@)";
            $feed->{error}=1;
            debug($feed->{message});
            next;
        }
        if (! $f) {
            $feed->{message}=XML::Feed->errstr;
            $feed->{error}=1;
            debug($feed->{message});
            next;
        }

        foreach my $entry ($f->entries) {
            add_page(
                feed => $feed,
                copyright => $f->copyright,
                title => defined $entry->title ? decode_entities($entry->title) : "untitled",
                link => $entry->link,
                content => defined $entry->content->body ? $entry->content->body : "",
                guid => defined $entry->id ? $entry->id : time."_".$feed->name,
                ctime => $entry->issued ? ($entry->issued->epoch || time) : time,
            );
        }
    }
} #}}}

sub add_page (@) { #{{{
    my %params=@_;
    
    my $feed=$params{feed};
    my $guid={};
    my $mtime;
    if (exists $guids{$params{guid}}) {
        # updating an existing post
        $guid=$guids{$params{guid}};
        return if $guid->{expired};
    }
    else {
        # new post
        $guid->{guid}=$params{guid};
        $guids{$params{guid}}=$guid;
        $mtime=$params{ctime};
        $feed->{numposts}++;
        $feed->{newposts}++;

        # assign it an unused page
        my $page=IkiWiki::titlepage($params{title});
        # escape slashes and periods in title so it doesn't specify
        # directory name or trigger ".." disallowing code.
        $page=~s!([/.])!"__".ord($1)."__"!eg;
        $page=$feed->{dir}."/".$page;
        ($page)=$page=~/$config{wiki_file_regexp}/;
        if (! defined $page || ! length $page) {
            $page=$feed->{dir}."/item";
        }
        my $c="";
        while (exists $IkiWiki::pagecase{lc $page.$c} ||
               -e pagefile($page.$c)) {
            $c++
        }

        # Make sure that the file name isn't too long. 
        # NB: This doesn't check for path length limits.
        my $max=POSIX::pathconf($config{srcdir}, &POSIX::_PC_NAME_MAX);
        if (defined $max && length(htmlfn($page)) >= $max) {
            $c="";
            $page=$feed->{dir}."/item";
            while (exists $IkiWiki::pagecase{lc $page.$c} ||
                   -e pagefile($page.$c)) {
                $c++
            }
        }

        $guid->{page}=$page;
        debug(sprintf(gettext("creating new page %s"), $page));
    }
    $guid->{feed}=$feed->{name};
    
    # To write or not to write? Need to avoid writing unchanged pages
    # to avoid unneccessary rebuilding. The mtime from rss cannot be
    # trusted; let's use a digest.
    eval q{use Digest::MD5 'md5_hex'};
    error($@) if $@;
    require Encode;
    my $digest=md5_hex(Encode::encode_utf8($params{content}));
    return unless ! exists $guid->{md5} || $guid->{md5} ne $digest || $config{rebuild};
    $guid->{md5}=$digest;

    # Create the page.
    my $template=template("aggregatepost.tmpl", blind_cache => 1);
    $template->param(title => $params{title})
        if defined $params{title} && length($params{title});
    $template->param(content => htmlescape(htmlabs($params{content}, $feed->{feedurl})));
    $template->param(name => $feed->{name});
    $template->param(url => $feed->{url});
    $template->param(copyright => $params{copyright})
        if defined $params{copyright} && length $params{copyright};
    $template->param(permalink => urlabs($params{link}, $feed->{feedurl}))
        if defined $params{link};
    if (ref $feed->{tags}) {
        $template->param(tags => [map { tag => $_ }, @{$feed->{tags}}]);
    }
    writefile(htmlfn($guid->{page}), $config{srcdir},
        $template->output);

    # Set the mtime, this lets the build process get the right creation
    # time on record for the new page.
    utime $mtime, $mtime, pagefile($guid->{page})
        if defined $mtime && $mtime <= time;
} #}}}

sub htmlescape ($) { #{{{
    # escape accidental wikilinks and preprocessor stuff
    my $html=shift;
    $html=~s/(?<!\\)\[\[/\\\[\[/g;
    return $html;
} #}}}

sub urlabs ($$) { #{{{
    my $url=shift;
    my $urlbase=shift;

    URI->new_abs($url, $urlbase)->as_string;
} #}}}

sub htmlabs ($$) { #{{{
    # Convert links in html from relative to absolute.
    # Note that this is a heuristic, which is not specified by the rss
    # spec and may not be right for all feeds. Also, see Debian
    # bug #381359.
    my $html=shift;
    my $urlbase=shift;

    my $ret="";
    my $p = HTML::Parser->new(api_version => 3);
    $p->handler(default => sub { $ret.=join("", @_) }, "text");
    $p->handler(start => sub {
        my ($tagname, $pos, $text) = @_;
        if (ref $HTML::Tagset::linkElements{$tagname}) {
            while (4 <= @$pos) {
                # use attribute sets from right to left
                # to avoid invalidating the offsets
                # when replacing the values
                my($k_offset, $k_len, $v_offset, $v_len) =
                    splice(@$pos, -4);
                my $attrname = lc(substr($text, $k_offset, $k_len));
                next unless grep { $_ eq $attrname } @{$HTML::Tagset::linkElements{$tagname}};
                next unless $v_offset; # 0 v_offset means no value
                my $v = substr($text, $v_offset, $v_len);
                $v =~ s/^([\'\"])(.*)\1$/$2/;
                my $new_v=urlabs($v, $urlbase);
                $new_v =~ s/\"/&quot;/g; # since we quote with ""
                substr($text, $v_offset, $v_len) = qq("$new_v");
            }
        }
        $ret.=$text;
    }, "tagname, tokenpos, text");
    $p->parse($html);
    $p->eof;

    return $ret;
} #}}}

sub pagefile ($) { #{{{
    my $page=shift;

    return "$config{srcdir}/".htmlfn($page);
} #}}}

sub htmlfn ($) { #{{{
    return shift().".".$config{htmlext};
} #}}}

my $aggregatelock;

sub lockaggregate () { #{{{
    # Take an exclusive lock to prevent multiple concurrent aggregators.
    # Returns true if the lock was aquired.
    if (! -d $config{wikistatedir}) {
        mkdir($config{wikistatedir});
    }
    open($aggregatelock, '>', "$config{wikistatedir}/aggregatelock") ||
        error ("cannot open to $config{wikistatedir}/aggregatelock: $!");
    if (! flock($aggregatelock, 2 | 4)) { # LOCK_EX | LOCK_NB
        close($aggregatelock) || error("failed closing aggregatelock: $!");
        return 0;
    }
    return 1;
} #}}}

sub unlockaggregate () { #{{{
    return close($aggregatelock) if $aggregatelock;
    return;
} #}}}

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