IkiWiki/Plugin/aggregate.pm

   1 #!/usr/bin/perl
   2 # Feed aggregation plugin.
   3 package IkiWiki::Plugin::aggregate;
   4
   5 use warnings;
   6 use strict;
   7 use IkiWiki 2.00;
   8 use HTML::Parser;
   9 use HTML::Tagset;
  10 use HTML::Entities;
  11 use URI;
  12 use open qw{:utf8 :std};
  13
  14 my %feeds;
  15 my %guids;
  16
  17 sub import { #{{{
  18         hook(type => "getopt", id => "aggregate", call => \&getopt);
  19         hook(type => "checkconfig", id => "aggregate", call => \&checkconfig);
  20         hook(type => "needsbuild", id => "aggregate", call => \&needsbuild);
  21         hook(type => "preprocess", id => "aggregate", call => \&preprocess);
  22         hook(type => "delete", id => "aggregate", call => \&delete);
  23         hook(type => "savestate", id => "aggregate", call => \&savestate);
  24         if (exists $config{aggregate_webtrigger} && $config{aggregate_webtrigger}) {
  25                 hook(type => "cgi", id => "aggregate", call => \&cgi);
  26         }
  27 } # }}}
  28
  29 sub getopt () { #{{{
  30         eval q{use Getopt::Long};
  31         error($@) if $@;
  32         Getopt::Long::Configure('pass_through');
  33         GetOptions(
  34                 "aggregate" => \$config{aggregate},
  35                 "aggregateinternal!" => \$config{aggregateinternal},
  36         );
  37 } #}}}
  38
  39 sub checkconfig () { #{{{
  40         if ($config{aggregate} && ! ($config{post_commit} &&
  41                                      IkiWiki::commit_hook_enabled())) {
  42                 launchaggregation();
  43         }
  44 } #}}}
  45
  46 sub cgi ($) { #{{{
  47         my $cgi=shift;
  48
  49         if (defined $cgi->param('do') &&
  50             $cgi->param("do") eq "aggregate_webtrigger") {
  51                 $|=1;
  52                 print "Content-Type: text/plain\n\n";
  53                 $config{cgi}=0;
  54                 $config{verbose}=1;
  55                 $config{syslog}=0;
  56                 print gettext("Aggregation triggered via web.")."\n\n";
  57                 if (launchaggregation()) {
  58                         IkiWiki::lockwiki();
  59                         IkiWiki::loadindex();
  60                         require IkiWiki::Render;
  61                         IkiWiki::refresh();
  62                         IkiWiki::saveindex();
  63                 }
  64                 else {
  65                         print gettext("Nothing to do right now, all feeds are up-to-date!")."\n";
  66                 }
  67                 exit 0;
  68         }
  69 } #}}}
  70
  71 sub launchaggregation () { #{{{
  72         # See if any feeds need aggregation.
  73         loadstate();
  74         my @feeds=needsaggregate();
  75         return unless @feeds;
  76         if (! lockaggregate()) {
  77                 debug("an aggregation process is already running");
  78                 return;
  79         }
  80         # force a later rebuild of source pages
  81         $IkiWiki::forcerebuild{$_->{sourcepage}}=1
  82                 foreach @feeds;
  83
  84         # Fork a child process to handle the aggregation.
  85         # The parent process will then handle building the
  86         # result. This avoids messy code to clear state
  87         # accumulated while aggregating.
  88         defined(my $pid = fork) or error("Can't fork: $!");
  89         if (! $pid) {
  90                 IkiWiki::loadindex();
  91                 # Aggregation happens without the main wiki lock
  92                 # being held. This allows editing pages etc while
  93                 # aggregation is running.
  94                 aggregate(@feeds);
  95
  96                 IkiWiki::lockwiki;
  97                 # Merge changes, since aggregation state may have
  98                 # changed on disk while the aggregation was happening.
  99                 mergestate();
 100                 expire();
 101                 savestate();
 102                 IkiWiki::unlockwiki;
 103                 exit 0;
 104         }
 105         waitpid($pid,0);
 106         if ($?) {
 107                 error "aggregation failed with code $?";
 108         }
 109
 110         clearstate();
 111         unlockaggregate();
 112
 113         return 1;
 114 } #}}}
 115
 116 # Used by ikiwiki-transition aggregateinternal.
 117 sub migrate_to_internal { #{{{
 118         if (! lockaggregate()) {
 119                 error("an aggregation process is currently running");
 120         }
 121
 122         IkiWiki::lockwiki();
 123         loadstate();
 124         $config{verbose}=1;
 125
 126         foreach my $data (values %guids) {
 127                 next unless $data->{page};
 128
 129                 $config{aggregateinternal} = 0;
 130                 my $oldname = pagefile($data->{page});
 131
 132                 $config{aggregateinternal} = 1;
 133                 my $newname = pagefile($data->{page});
 134
 135                 debug "moving $oldname -> $newname";
 136                 if (-e $newname) {
 137                         if (-e $oldname) {
 138                                 error("$newname already exists");
 139                         }
 140                         else {
 141                                 debug("already renamed to $newname?");
 142                         }
 143                 }
 144                 elsif (-e $oldname) {
 145                         rename($oldname, $newname) || error("$!");
 146                 }
 147                 else {
 148                         debug("$oldname not found");
 149                 }
 150         }
 151
 152         savestate();
 153         IkiWiki::unlockwiki;
 154
 155         unlockaggregate();
 156 } #}}}
 157
 158 sub needsbuild (@) { #{{{
 159         my $needsbuild=shift;
 160
 161         loadstate();
 162
 163         foreach my $feed (values %feeds) {
 164                 if (exists $pagesources{$feed->{sourcepage}} &&
 165                     grep { $_ eq $pagesources{$feed->{sourcepage}} } @$needsbuild) {
 166                         # Mark all feeds originating on this page as
 167                         # not yet seen; preprocess will unmark those that
 168                         # still exist.
 169                         markunseen($feed->{sourcepage});
 170                 }
 171         }
 172 } # }}}
 173
 174 sub preprocess (@) { #{{{
 175         my %params=@_;
 176
 177         foreach my $required (qw{name url}) {
 178                 if (! exists $params{$required}) {
 179                         error sprintf(gettext("missing %s parameter"), $required)
 180                 }
 181         }
 182
 183         my $feed={};
 184         my $name=$params{name};
 185         if (exists $feeds{$name}) {
 186                 $feed=$feeds{$name};
 187         }
 188         else {
 189                 $feeds{$name}=$feed;
 190         }
 191         $feed->{name}=$name;
 192         $feed->{sourcepage}=$params{page};
 193         $feed->{url}=$params{url};
 194         my $dir=exists $params{dir} ? $params{dir} : $params{page}."/".IkiWiki::titlepage($params{name});
 195         $dir=~s/^\/+//;
 196         ($dir)=$dir=~/$config{wiki_file_regexp}/;
 197         $feed->{dir}=$dir;
 198         $feed->{feedurl}=defined $params{feedurl} ? $params{feedurl} : "";
 199         $feed->{updateinterval}=defined $params{updateinterval} ? $params{updateinterval} * 60 : 15 * 60;
 200         $feed->{expireage}=defined $params{expireage} ? $params{expireage} : 0;
 201         $feed->{expirecount}=defined $params{expirecount} ? $params{expirecount} : 0;
 202         if (exists $params{template}) {
 203                 $params{template}=~s/[^-_a-zA-Z0-9]+//g;
 204         }
 205         else {
 206                 $params{template} = "aggregatepost"
 207         }
 208         $feed->{template}=$params{template} . ".tmpl";
 209         delete $feed->{unseen};
 210         $feed->{lastupdate}=0 unless defined $feed->{lastupdate};
 211         $feed->{numposts}=0 unless defined $feed->{numposts};
 212         $feed->{newposts}=0 unless defined $feed->{newposts};
 213         $feed->{message}=gettext("new feed") unless defined $feed->{message};
 214         $feed->{error}=0 unless defined $feed->{error};
 215         $feed->{tags}=[];
 216         while (@_) {
 217                 my $key=shift;
 218                 my $value=shift;
 219                 if ($key eq 'tag') {
 220                         push @{$feed->{tags}}, $value;
 221                 }
 222         }
 223
 224         return "<a href=\"".$feed->{url}."\">".$feed->{name}."</a>: ".
 225                ($feed->{error} ? "<em>" : "").$feed->{message}.
 226                ($feed->{error} ? "</em>" : "").
 227                " (".$feed->{numposts}." ".gettext("posts").
 228                ($feed->{newposts} ? "; ".$feed->{newposts}.
 229                                     " ".gettext("new") : "").
 230                ")";
 231 } # }}}
 232
 233 sub delete (@) { #{{{
 234         my @files=@_;
 235
 236         # Remove feed data for removed pages.
 237         foreach my $file (@files) {
 238                 my $page=pagename($file);
 239                 markunseen($page);
 240         }
 241 } #}}}
 242
 243 sub markunseen ($) { #{{{
 244         my $page=shift;
 245
 246         foreach my $id (keys %feeds) {
 247                 if ($feeds{$id}->{sourcepage} eq $page) {
 248                         $feeds{$id}->{unseen}=1;
 249                 }
 250         }
 251 } #}}}
 252
 253 my $state_loaded=0;
 254
 255 sub loadstate () { #{{{
 256         return if $state_loaded;
 257         $state_loaded=1;
 258         if (-e "$config{wikistatedir}/aggregate") {
 259                 open(IN, "$config{wikistatedir}/aggregate") ||
 260                         die "$config{wikistatedir}/aggregate: $!";
 261                 while (<IN>) {
 262                         $_=IkiWiki::possibly_foolish_untaint($_);
 263                         chomp;
 264                         my $data={};
 265                         foreach my $i (split(/ /, $_)) {
 266                                 my ($field, $val)=split(/=/, $i, 2);
 267                                 if ($field eq "name" || $field eq "feed" ||
 268                                     $field eq "guid" || $field eq "message") {
 269                                         $data->{$field}=decode_entities($val, " \t\n");
 270                                 }
 271                                 elsif ($field eq "tag") {
 272                                         push @{$data->{tags}}, $val;
 273                                 }
 274                                 else {
 275                                         $data->{$field}=$val;
 276                                 }
 277                         }
 278
 279                         if (exists $data->{name}) {
 280                                 $feeds{$data->{name}}=$data;
 281                         }
 282                         elsif (exists $data->{guid}) {
 283                                 $guids{$data->{guid}}=$data;
 284                         }
 285                 }
 286
 287                 close IN;
 288         }
 289 } #}}}
 290
 291 sub savestate () { #{{{
 292         return unless $state_loaded;
 293         garbage_collect();
 294         my $newfile="$config{wikistatedir}/aggregate.new";
 295         my $cleanup = sub { unlink($newfile) };
 296         open (OUT, ">$newfile") || error("open $newfile: $!", $cleanup);
 297         foreach my $data (values %feeds, values %guids) {
 298                 my @line;
 299                 foreach my $field (keys %$data) {
 300                         if ($field eq "name" || $field eq "feed" ||
 301                             $field eq "guid" || $field eq "message") {
 302                                 push @line, "$field=".encode_entities($data->{$field}, " \t\n");
 303                         }
 304                         elsif ($field eq "tags") {
 305                                 push @line, "tag=$_" foreach @{$data->{tags}};
 306                         }
 307                         else {
 308                                 push @line, "$field=".$data->{$field};
 309                         }
 310                 }
 311                 print OUT join(" ", @line)."\n" || error("write $newfile: $!", $cleanup);
 312         }
 313         close OUT || error("save $newfile: $!", $cleanup);
 314         rename($newfile, "$config{wikistatedir}/aggregate") ||
 315                 error("rename $newfile: $!", $cleanup);
 316 } #}}}
 317
 318 sub garbage_collect () { #{{{
 319         foreach my $name (keys %feeds) {
 320                 # remove any feeds that were not seen while building the pages
 321                 # that used to contain them
 322                 if ($feeds{$name}->{unseen}) {
 323                         delete $feeds{$name};
 324                 }
 325         }
 326
 327         foreach my $guid (values %guids) {
 328                 # any guid whose feed is gone should be removed
 329                 if (! exists $feeds{$guid->{feed}}) {
 330                         unlink pagefile($guid->{page})
 331                                 if exists $guid->{page};
 332                         delete $guids{$guid->{guid}};
 333                 }
 334                 # handle expired guids
 335                 elsif ($guid->{expired} && exists $guid->{page}) {
 336                         unlink pagefile($guid->{page});
 337                         delete $guid->{page};
 338                         delete $guid->{md5};
 339                 }
 340         }
 341 } #}}}
 342
 343 sub mergestate () { #{{{
 344         # Load the current state in from disk, and merge into it
 345         # values from the state in memory that might have changed
 346         # during aggregation.
 347         my %myfeeds=%feeds;
 348         my %myguids=%guids;
 349         clearstate();
 350         loadstate();
 351
 352         # All that can change in feed state during aggregation is a few
 353         # fields.
 354         foreach my $name (keys %myfeeds) {
 355                 if (exists $feeds{$name}) {
 356                         foreach my $field (qw{message lastupdate numposts
 357                                               newposts error}) {
 358                                 $feeds{$name}->{$field}=$myfeeds{$name}->{$field};
 359                         }
 360                 }
 361         }
 362
 363         # New guids can be created during aggregation.
 364         # It's also possible that guids were removed from the on-disk state
 365         # while the aggregation was in process. That would only happen if
 366         # their feed was also removed, so any removed guids added back here
 367         # will be garbage collected later.
 368         foreach my $guid (keys %myguids) {
 369                 if (! exists $guids{$guid}) {
 370                         $guids{$guid}=$myguids{$guid};
 371                 }
 372         }
 373 } #}}}
 374
 375 sub clearstate () { #{{{
 376         %feeds=();
 377         %guids=();
 378         $state_loaded=0;
 379 } #}}}
 380
 381 sub expire () { #{{{
 382         foreach my $feed (values %feeds) {
 383                 next unless $feed->{expireage} || $feed->{expirecount};
 384                 my $count=0;
 385                 my %seen;
 386                 foreach my $item (sort { $IkiWiki::pagectime{$b->{page}} <=> $IkiWiki::pagectime{$a->{page}} }
 387                                   grep { exists $_->{page} && $_->{feed} eq $feed->{name} && $IkiWiki::pagectime{$_->{page}} }
 388                                   values %guids) {
 389                         if ($feed->{expireage}) {
 390                                 my $days_old = (time - $IkiWiki::pagectime{$item->{page}}) / 60 / 60 / 24;
 391                                 if ($days_old > $feed->{expireage}) {
 392                                         debug(sprintf(gettext("expiring %s (%s days old)"),
 393                                                 $item->{page}, int($days_old)));
 394                                         $item->{expired}=1;
 395                                 }
 396                         }
 397                         elsif ($feed->{expirecount} &&
 398                                $count >= $feed->{expirecount}) {
 399                                 debug(sprintf(gettext("expiring %s"), $item->{page}));
 400                                 $item->{expired}=1;
 401                         }
 402                         else {
 403                                 if (! $seen{$item->{page}}) {
 404                                         $seen{$item->{page}}=1;
 405                                         $count++;
 406                                 }
 407                         }
 408                 }
 409         }
 410 } #}}}
 411
 412 sub needsaggregate () { #{{{
 413         return values %feeds if $config{rebuild};
 414         return grep { time - $_->{lastupdate} >= $_->{updateinterval} } values %feeds;
 415 } #}}}
 416
 417 sub aggregate (@) { #{{{
 418         eval q{use XML::Feed};
 419         error($@) if $@;
 420         eval q{use URI::Fetch};
 421         error($@) if $@;
 422
 423         foreach my $feed (@_) {
 424                 $feed->{lastupdate}=time;
 425                 $feed->{newposts}=0;
 426                 $feed->{message}=sprintf(gettext("processed ok at %s"),
 427                         displaytime($feed->{lastupdate}));
 428                 $feed->{error}=0;
 429
 430                 debug(sprintf(gettext("checking feed %s ..."), $feed->{name}));
 431
 432                 if (! length $feed->{feedurl}) {
 433                         my @urls=XML::Feed->find_feeds($feed->{url});
 434                         if (! @urls) {
 435                                 $feed->{message}=sprintf(gettext("could not find feed at %s"), $feed->{url});
 436                                 $feed->{error}=1;
 437                                 debug($feed->{message});
 438                                 next;
 439                         }
 440                         $feed->{feedurl}=pop @urls;
 441                 }
 442                 my $res=URI::Fetch->fetch($feed->{feedurl});
 443                 if (! $res) {
 444                         $feed->{message}=URI::Fetch->errstr;
 445                         $feed->{error}=1;
 446                         debug($feed->{message});
 447                         next;
 448                 }
 449                 if ($res->status == URI::Fetch::URI_GONE()) {
 450                         $feed->{message}=gettext("feed not found");
 451                         $feed->{error}=1;
 452                         debug($feed->{message});
 453                         next;
 454                 }
 455                 my $content=$res->content;
 456                 my $f=eval{XML::Feed->parse(\$content)};
 457                 if ($@) {
 458                         # One common cause of XML::Feed crashing is a feed
 459                         # that contains invalid UTF-8 sequences. Convert
 460                         # feed to ascii to try to work around.
 461                         $feed->{message}.=" ".sprintf(gettext("(invalid UTF-8 stripped from feed)"));
 462                         $content=Encode::decode_utf8($content, 0);
 463                         $f=eval{XML::Feed->parse(\$content)};
 464                 }
 465                 if ($@) {
 466                         # Another possibility is badly escaped entities.
 467                         $feed->{message}.=" ".sprintf(gettext("(feed entities escaped)"));
 468                         $content=~s/\&(?!amp)(\w+);/&amp;$1;/g;
 469                         $content=Encode::decode_utf8($content, 0);
 470                         $f=eval{XML::Feed->parse(\$content)};
 471                 }
 472                 if ($@) {
 473                         $feed->{message}=gettext("feed crashed XML::Feed!")." ($@)";
 474                         $feed->{error}=1;
 475                         debug($feed->{message});
 476                         next;
 477                 }
 478                 if (! $f) {
 479                         $feed->{message}=XML::Feed->errstr;
 480                         $feed->{error}=1;
 481                         debug($feed->{message});
 482                         next;
 483                 }
 484
 485                 foreach my $entry ($f->entries) {
 486                         add_page(
 487                                 feed => $feed,
 488                                 copyright => $f->copyright,
 489                                 title => defined $entry->title ? decode_entities($entry->title) : "untitled",
 490                                 link => $entry->link,
 491                                 content => defined $entry->content->body ? $entry->content->body : "",
 492                                 guid => defined $entry->id ? $entry->id : time."_".$feed->{name},
 493                                 ctime => $entry->issued ? ($entry->issued->epoch || time) : time,
 494                         );
 495                 }
 496         }
 497 } #}}}
 498
 499 sub add_page (@) { #{{{
 500         my %params=@_;
 501
 502         my $feed=$params{feed};
 503         my $guid={};
 504         my $mtime;
 505         if (exists $guids{$params{guid}}) {
 506                 # updating an existing post
 507                 $guid=$guids{$params{guid}};
 508                 return if $guid->{expired};
 509         }
 510         else {
 511                 # new post
 512                 $guid->{guid}=$params{guid};
 513                 $guids{$params{guid}}=$guid;
 514                 $mtime=$params{ctime};
 515                 $feed->{numposts}++;
 516                 $feed->{newposts}++;
 517
 518                 # assign it an unused page
 519                 my $page=IkiWiki::titlepage($params{title});
 520                 # escape slashes and periods in title so it doesn't specify
 521                 # directory name or trigger ".." disallowing code.
 522                 $page=~s!([/.])!"__".ord($1)."__"!eg;
 523                 $page=$feed->{dir}."/".$page;
 524                 ($page)=$page=~/$config{wiki_file_regexp}/;
 525                 if (! defined $page || ! length $page) {
 526                         $page=$feed->{dir}."/item";
 527                 }
 528                 my $c="";
 529                 while (exists $IkiWiki::pagecase{lc $page.$c} ||
 530                        -e pagefile($page.$c)) {
 531                         $c++
 532                 }
 533
 534                 # Make sure that the file name isn't too long.
 535                 # NB: This doesn't check for path length limits.
 536                 my $max=POSIX::pathconf($config{srcdir}, &POSIX::_PC_NAME_MAX);
 537                 if (defined $max && length(htmlfn($page)) >= $max) {
 538                         $c="";
 539                         $page=$feed->{dir}."/item";
 540                         while (exists $IkiWiki::pagecase{lc $page.$c} ||
 541                                -e pagefile($page.$c)) {
 542                                 $c++
 543                         }
 544                 }
 545
 546                 $guid->{page}=$page;
 547                 debug(sprintf(gettext("creating new page %s"), $page));
 548         }
 549         $guid->{feed}=$feed->{name};
 550
 551         # To write or not to write? Need to avoid writing unchanged pages
 552         # to avoid unneccessary rebuilding. The mtime from rss cannot be
 553         # trusted; let's use a digest.
 554         eval q{use Digest::MD5 'md5_hex'};
 555         error($@) if $@;
 556         require Encode;
 557         my $digest=md5_hex(Encode::encode_utf8($params{content}));
 558         return unless ! exists $guid->{md5} || $guid->{md5} ne $digest || $config{rebuild};
 559         $guid->{md5}=$digest;
 560
 561         # Create the page.
 562         my $template=template($feed->{template}, blind_cache => 1);
 563         $template->param(title => $params{title})
 564                 if defined $params{title} && length($params{title});
 565         $template->param(content => htmlescape(htmlabs($params{content}, $feed->{feedurl})));
 566         $template->param(name => $feed->{name});
 567         $template->param(url => $feed->{url});
 568         $template->param(copyright => $params{copyright})
 569                 if defined $params{copyright} && length $params{copyright};
 570         $template->param(permalink => urlabs($params{link}, $feed->{feedurl}))
 571                 if defined $params{link};
 572         if (ref $feed->{tags}) {
 573                 $template->param(tags => [map { tag => $_ }, @{$feed->{tags}}]);
 574         }
 575         writefile(htmlfn($guid->{page}), $config{srcdir},
 576                 $template->output);
 577
 578         # Set the mtime, this lets the build process get the right creation
 579         # time on record for the new page.
 580         utime $mtime, $mtime, pagefile($guid->{page})
 581                 if defined $mtime && $mtime <= time;
 582 } #}}}
 583
 584 sub htmlescape ($) { #{{{
 585         # escape accidental wikilinks and preprocessor stuff
 586         my $html=shift;
 587         $html=~s/(?<!\\)\[\[/\\\[\[/g;
 588         return $html;
 589 } #}}}
 590
 591 sub urlabs ($$) { #{{{
 592         my $url=shift;
 593         my $urlbase=shift;
 594
 595         URI->new_abs($url, $urlbase)->as_string;
 596 } #}}}
 597
 598 sub htmlabs ($$) { #{{{
 599         # Convert links in html from relative to absolute.
 600         # Note that this is a heuristic, which is not specified by the rss
 601         # spec and may not be right for all feeds. Also, see Debian
 602         # bug #381359.
 603         my $html=shift;
 604         my $urlbase=shift;
 605
 606         my $ret="";
 607         my $p = HTML::Parser->new(api_version => 3);
 608         $p->handler(default => sub { $ret.=join("", @_) }, "text");
 609         $p->handler(start => sub {
 610                 my ($tagname, $pos, $text) = @_;
 611                 if (ref $HTML::Tagset::linkElements{$tagname}) {
 612                         while (4 <= @$pos) {
 613                                 # use attribute sets from right to left
 614                                 # to avoid invalidating the offsets
 615                                 # when replacing the values
 616                                 my($k_offset, $k_len, $v_offset, $v_len) =
 617                                         splice(@$pos, -4);
 618                                 my $attrname = lc(substr($text, $k_offset, $k_len));
 619                                 next unless grep { $_ eq $attrname } @{$HTML::Tagset::linkElements{$tagname}};
 620                                 next unless $v_offset; # 0 v_offset means no value
 621                                 my $v = substr($text, $v_offset, $v_len);
 622                                 $v =~ s/^([\'\"])(.*)\1$/$2/;
 623                                 my $new_v=urlabs($v, $urlbase);
 624                                 $new_v =~ s/\"/&quot;/g; # since we quote with ""
 625                                 substr($text, $v_offset, $v_len) = qq("$new_v");
 626                         }
 627                 }
 628                 $ret.=$text;
 629         }, "tagname, tokenpos, text");
 630         $p->parse($html);
 631         $p->eof;
 632
 633         return $ret;
 634 } #}}}
 635
 636 sub pagefile ($) { #{{{
 637         my $page=shift;
 638
 639         return "$config{srcdir}/".htmlfn($page);
 640 } #}}}
 641
 642 sub htmlfn ($) { #{{{
 643         return shift().".".($config{aggregateinternal} ? "_" : "").$config{htmlext};
 644 } #}}}
 645
 646 my $aggregatelock;
 647
 648 sub lockaggregate () { #{{{
 649         # Take an exclusive lock to prevent multiple concurrent aggregators.
 650         # Returns true if the lock was aquired.
 651         if (! -d $config{wikistatedir}) {
 652                 mkdir($config{wikistatedir});
 653         }
 654         open($aggregatelock, '>', "$config{wikistatedir}/aggregatelock") ||
 655                 error ("cannot open to $config{wikistatedir}/aggregatelock: $!");
 656         if (! flock($aggregatelock, 2 | 4)) { # LOCK_EX | LOCK_NB
 657                 close($aggregatelock) || error("failed closing aggregatelock: $!");
 658                 return 0;
 659         }
 660         return 1;
 661 } #}}}
 662
 663 sub unlockaggregate () { #{{{
 664         return close($aggregatelock) if $aggregatelock;
 665         return;
 666 } #}}}
 667
 668 1