Andrew's git - gitweb.git/blob - contrib/mw-to-git/git-remote-mediawiki.perl

   1#! /usr/bin/perl
   2
   3# Copyright (C) 2011
   4#     Jérémie Nikaes <jeremie.nikaes@ensimag.imag.fr>
   5#     Arnaud Lacurie <arnaud.lacurie@ensimag.imag.fr>
   6#     Claire Fousse <claire.fousse@ensimag.imag.fr>
   7#     David Amouyal <david.amouyal@ensimag.imag.fr>
   8#     Matthieu Moy <matthieu.moy@grenoble-inp.fr>
   9# License: GPL v2 or later
  10
  11# Gateway between Git and MediaWiki.
  12# Documentation & bugtracker: https://github.com/moy/Git-Mediawiki/
  13
  14use strict;
  15use MediaWiki::API;
  16use Git;
  17use DateTime::Format::ISO8601;
  18use warnings;
  19
  20# By default, use UTF-8 to communicate with Git and the user
  21binmode STDERR, ':encoding(UTF-8)';
  22binmode STDOUT, ':encoding(UTF-8)';
  23
  24use URI::Escape;
  25
  26# Mediawiki filenames can contain forward slashes. This variable decides by which pattern they should be replaced
  27use constant SLASH_REPLACEMENT => '%2F';
  28
  29# It's not always possible to delete pages (may require some
  30# privileges). Deleted pages are replaced with this content.
  31use constant DELETED_CONTENT => "[[Category:Deleted]]\n";
  32
  33# It's not possible to create empty pages. New empty files in Git are
  34# sent with this content instead.
  35use constant EMPTY_CONTENT => "<!-- empty page -->\n";
  36
  37# used to reflect file creation or deletion in diff.
  38use constant NULL_SHA1 => '0000000000000000000000000000000000000000';
  39
  40# Used on Git's side to reflect empty edit messages on the wiki
  41use constant EMPTY_MESSAGE => '*Empty MediaWiki Message*';
  42
  43my $remotename = $ARGV[0];
  44my $url = $ARGV[1];
  45
  46# Accept both space-separated and multiple keys in config file.
  47# Spaces should be written as _ anyway because we'll use chomp.
  48my @tracked_pages = split(/[ \n]/, run_git("config --get-all remote.${remotename}.pages"));
  49chomp(@tracked_pages);
  50
  51# Just like @tracked_pages, but for MediaWiki categories.
  52my @tracked_categories = split(/[ \n]/, run_git("config --get-all remote.${remotename}.categories"));
  53chomp(@tracked_categories);
  54
  55# Import media files on pull
  56my $import_media = run_git("config --get --bool remote.${remotename}.mediaimport");
  57chomp($import_media);
  58$import_media = ($import_media eq 'true');
  59
  60# Export media files on push
  61my $export_media = run_git("config --get --bool remote.${remotename}.mediaexport");
  62chomp($export_media);
  63$export_media = !($export_media eq 'false');
  64
  65my $wiki_login = run_git("config --get remote.${remotename}.mwLogin");
  66# Note: mwPassword is discourraged. Use the credential system instead.
  67my $wiki_passwd = run_git("config --get remote.${remotename}.mwPassword");
  68my $wiki_domain = run_git("config --get remote.${remotename}.mwDomain");
  69chomp($wiki_login);
  70chomp($wiki_passwd);
  71chomp($wiki_domain);
  72
  73# Import only last revisions (both for clone and fetch)
  74my $shallow_import = run_git("config --get --bool remote.${remotename}.shallow");
  75chomp($shallow_import);
  76$shallow_import = ($shallow_import eq 'true');
  77
  78# Fetch (clone and pull) by revisions instead of by pages. This behavior
  79# is more efficient when we have a wiki with lots of pages and we fetch
  80# the revisions quite often so that they concern only few pages.
  81# Possible values:
  82# - by_rev: perform one query per new revision on the remote wiki
  83# - by_page: query each tracked page for new revision
  84my $fetch_strategy = run_git("config --get remote.${remotename}.fetchStrategy");
  85unless ($fetch_strategy) {
  86        $fetch_strategy = run_git('config --get mediawiki.fetchStrategy');
  87}
  88chomp($fetch_strategy);
  89unless ($fetch_strategy) {
  90        $fetch_strategy = 'by_page';
  91}
  92
  93# Remember the timestamp corresponding to a revision id.
  94my %basetimestamps;
  95
  96# Dumb push: don't update notes and mediawiki ref to reflect the last push.
  97#
  98# Configurable with mediawiki.dumbPush, or per-remote with
  99# remote.<remotename>.dumbPush.
 100#
 101# This means the user will have to re-import the just-pushed
 102# revisions. On the other hand, this means that the Git revisions
 103# corresponding to MediaWiki revisions are all imported from the wiki,
 104# regardless of whether they were initially created in Git or from the
 105# web interface, hence all users will get the same history (i.e. if
 106# the push from Git to MediaWiki loses some information, everybody
 107# will get the history with information lost). If the import is
 108# deterministic, this means everybody gets the same sha1 for each
 109# MediaWiki revision.
 110my $dumb_push = run_git("config --get --bool remote.${remotename}.dumbPush");
 111unless ($dumb_push) {
 112        $dumb_push = run_git('config --get --bool mediawiki.dumbPush');
 113}
 114chomp($dumb_push);
 115$dumb_push = ($dumb_push eq 'true');
 116
 117my $wiki_name = $url;
 118$wiki_name =~ s{[^/]*://}{};
 119# If URL is like http://user:password@example.com/, we clearly don't
 120# want the password in $wiki_name. While we're there, also remove user
 121# and '@' sign, to avoid author like MWUser@HTTPUser@host.com
 122$wiki_name =~ s/^.*@//;
 123
 124# Commands parser
 125while (<STDIN>) {
 126        chomp;
 127
 128        if (!parse_command($_)) {
 129                last;
 130        }
 131
 132        BEGIN { $| = 1 } # flush STDOUT, to make sure the previous
 133                         # command is fully processed.
 134}
 135
 136########################## Functions ##############################
 137
 138sub parse_command {
 139        my ($line) = @_;
 140        my @cmd = split(/ /, $line);
 141        if (!defined $cmd[0]) {
 142                return 0;
 143        }
 144        if ($cmd[0] eq 'capabilities') {
 145                die("Too many arguments for capabilities\n")
 146                    if (defined($cmd[1]));
 147                mw_capabilities();
 148        } elsif ($cmd[0] eq 'list') {
 149                die("Too many arguments for list\n") if (defined($cmd[2]));
 150                mw_list($cmd[1]);
 151        } elsif ($cmd[0] eq 'import') {
 152                die("Invalid arguments for import\n")
 153                    if ($cmd[1] eq "" || defined($cmd[2]));
 154                mw_import($cmd[1]);
 155        } elsif ($cmd[0] eq 'option') {
 156                die("Too many arguments for option\n")
 157                    if ($cmd[1] eq "" || $cmd[2] eq "" || defined($cmd[3]));
 158                mw_option($cmd[1],$cmd[2]);
 159        } elsif ($cmd[0] eq 'push') {
 160                mw_push($cmd[1]);
 161        } else {
 162                print STDERR "Unknown command. Aborting...\n";
 163                return 0;
 164        }
 165        return 1;
 166}
 167
 168# MediaWiki API instance, created lazily.
 169my $mediawiki;
 170
 171sub mw_connect_maybe {
 172        if ($mediawiki) {
 173                return;
 174        }
 175        $mediawiki = MediaWiki::API->new;
 176        $mediawiki->{config}->{api_url} = "${url}/api.php";
 177        if ($wiki_login) {
 178                my %credential = (
 179                        'url' => $url,
 180                        'username' => $wiki_login,
 181                        'password' => $wiki_passwd
 182                );
 183                Git::credential(\%credential);
 184                my $request = {lgname => $credential{username},
 185                               lgpassword => $credential{password},
 186                               lgdomain => $wiki_domain};
 187                if ($mediawiki->login($request)) {
 188                        Git::credential(\%credential, 'approve');
 189                        print STDERR qq(Logged in mediawiki user "$credential{username}".\n);
 190                } else {
 191                        print STDERR qq(Failed to log in mediawiki user "$credential{username}" on ${url}\n);
 192                        print STDERR '  (error ' .
 193                                $mediawiki->{error}->{code} . ': ' .
 194                                $mediawiki->{error}->{details} . ")\n";
 195                        Git::credential(\%credential, 'reject');
 196                        exit 1;
 197                }
 198        }
 199        return;
 200}
 201
 202sub fatal_mw_error {
 203        my $action = shift;
 204        print STDERR "fatal: could not $action.\n";
 205        print STDERR "fatal: '$url' does not appear to be a mediawiki\n";
 206        if ($url =~ /^https/) {
 207                print STDERR "fatal: make sure '$url/api.php' is a valid page\n";
 208                print STDERR "fatal: and the SSL certificate is correct.\n";
 209        } else {
 210                print STDERR "fatal: make sure '$url/api.php' is a valid page.\n";
 211        }
 212        print STDERR "fatal: (error " .
 213            $mediawiki->{error}->{code} . ': ' .
 214            $mediawiki->{error}->{details} . ")\n";
 215        exit 1;
 216}
 217
 218## Functions for listing pages on the remote wiki
 219sub get_mw_tracked_pages {
 220        my $pages = shift;
 221        get_mw_page_list(\@tracked_pages, $pages);
 222        return;
 223}
 224
 225sub get_mw_page_list {
 226        my $page_list = shift;
 227        my $pages = shift;
 228        my @some_pages = @$page_list;
 229        while (@some_pages) {
 230                my $last_page = 50;
 231                if ($#some_pages < $last_page) {
 232                        $last_page = $#some_pages;
 233                }
 234                my @slice = @some_pages[0..$last_page];
 235                get_mw_first_pages(\@slice, $pages);
 236                @some_pages = @some_pages[51..$#some_pages];
 237        }
 238        return;
 239}
 240
 241sub get_mw_tracked_categories {
 242        my $pages = shift;
 243        foreach my $category (@tracked_categories) {
 244                if (index($category, ':') < 0) {
 245                        # Mediawiki requires the Category
 246                        # prefix, but let's not force the user
 247                        # to specify it.
 248                        $category = "Category:${category}";
 249                }
 250                my $mw_pages = $mediawiki->list( {
 251                        action => 'query',
 252                        list => 'categorymembers',
 253                        cmtitle => $category,
 254                        cmlimit => 'max' } )
 255                        || die $mediawiki->{error}->{code} . ': '
 256                                . $mediawiki->{error}->{details} . "\n";
 257                foreach my $page (@{$mw_pages}) {
 258                        $pages->{$page->{title}} = $page;
 259                }
 260        }
 261        return;
 262}
 263
 264sub get_mw_all_pages {
 265        my $pages = shift;
 266        # No user-provided list, get the list of pages from the API.
 267        my $mw_pages = $mediawiki->list({
 268                action => 'query',
 269                list => 'allpages',
 270                aplimit => 'max'
 271        });
 272        if (!defined($mw_pages)) {
 273                fatal_mw_error("get the list of wiki pages");
 274        }
 275        foreach my $page (@{$mw_pages}) {
 276                $pages->{$page->{title}} = $page;
 277        }
 278        return;
 279}
 280
 281# queries the wiki for a set of pages. Meant to be used within a loop
 282# querying the wiki for slices of page list.
 283sub get_mw_first_pages {
 284        my $some_pages = shift;
 285        my @some_pages = @{$some_pages};
 286
 287        my $pages = shift;
 288
 289        # pattern 'page1|page2|...' required by the API
 290        my $titles = join('|', @some_pages);
 291
 292        my $mw_pages = $mediawiki->api({
 293                action => 'query',
 294                titles => $titles,
 295        });
 296        if (!defined($mw_pages)) {
 297                fatal_mw_error("query the list of wiki pages");
 298        }
 299        while (my ($id, $page) = each(%{$mw_pages->{query}->{pages}})) {
 300                if ($id < 0) {
 301                        print STDERR "Warning: page $page->{title} not found on wiki\n";
 302                } else {
 303                        $pages->{$page->{title}} = $page;
 304                }
 305        }
 306        return;
 307}
 308
 309# Get the list of pages to be fetched according to configuration.
 310sub get_mw_pages {
 311        mw_connect_maybe();
 312
 313        print STDERR "Listing pages on remote wiki...\n";
 314
 315        my %pages; # hash on page titles to avoid duplicates
 316        my $user_defined;
 317        if (@tracked_pages) {
 318                $user_defined = 1;
 319                # The user provided a list of pages titles, but we
 320                # still need to query the API to get the page IDs.
 321                get_mw_tracked_pages(\%pages);
 322        }
 323        if (@tracked_categories) {
 324                $user_defined = 1;
 325                get_mw_tracked_categories(\%pages);
 326        }
 327        if (!$user_defined) {
 328                get_mw_all_pages(\%pages);
 329        }
 330        if ($import_media) {
 331                print STDERR "Getting media files for selected pages...\n";
 332                if ($user_defined) {
 333                        get_linked_mediafiles(\%pages);
 334                } else {
 335                        get_all_mediafiles(\%pages);
 336                }
 337        }
 338        print STDERR (scalar keys %pages) . " pages found.\n";
 339        return %pages;
 340}
 341
 342# usage: $out = run_git("command args");
 343#        $out = run_git("command args", "raw"); # don't interpret output as UTF-8.
 344sub run_git {
 345        my $args = shift;
 346        my $encoding = (shift || 'encoding(UTF-8)');
 347        open(my $git, "-|:${encoding}", "git ${args}")
 348            or die "Unable to fork: $!\n";
 349        my $res = do {
 350                local $/ = undef;
 351                <$git>
 352        };
 353        close($git);
 354
 355        return $res;
 356}
 357
 358
 359sub get_all_mediafiles {
 360        my $pages = shift;
 361        # Attach list of all pages for media files from the API,
 362        # they are in a different namespace, only one namespace
 363        # can be queried at the same moment
 364        my $mw_pages = $mediawiki->list({
 365                action => 'query',
 366                list => 'allpages',
 367                apnamespace => get_mw_namespace_id('File'),
 368                aplimit => 'max'
 369        });
 370        if (!defined($mw_pages)) {
 371                print STDERR "fatal: could not get the list of pages for media files.\n";
 372                print STDERR "fatal: '$url' does not appear to be a mediawiki\n";
 373                print STDERR "fatal: make sure '$url/api.php' is a valid page.\n";
 374                exit 1;
 375        }
 376        foreach my $page (@{$mw_pages}) {
 377                $pages->{$page->{title}} = $page;
 378        }
 379        return;
 380}
 381
 382sub get_linked_mediafiles {
 383        my $pages = shift;
 384        my @titles = map { $_->{title} } values(%{$pages});
 385
 386        # The query is split in small batches because of the MW API limit of
 387        # the number of links to be returned (500 links max).
 388        my $batch = 10;
 389        while (@titles) {
 390                if ($#titles < $batch) {
 391                        $batch = $#titles;
 392                }
 393                my @slice = @titles[0..$batch];
 394
 395                # pattern 'page1|page2|...' required by the API
 396                my $mw_titles = join('|', @slice);
 397
 398                # Media files could be included or linked from
 399                # a page, get all related
 400                my $query = {
 401                        action => 'query',
 402                        prop => 'links|images',
 403                        titles => $mw_titles,
 404                        plnamespace => get_mw_namespace_id('File'),
 405                        pllimit => 'max'
 406                };
 407                my $result = $mediawiki->api($query);
 408
 409                while (my ($id, $page) = each(%{$result->{query}->{pages}})) {
 410                        my @media_titles;
 411                        if (defined($page->{links})) {
 412                                my @link_titles
 413                                    = map { $_->{title} } @{$page->{links}};
 414                                push(@media_titles, @link_titles);
 415                        }
 416                        if (defined($page->{images})) {
 417                                my @image_titles
 418                                    = map { $_->{title} } @{$page->{images}};
 419                                push(@media_titles, @image_titles);
 420                        }
 421                        if (@media_titles) {
 422                                get_mw_page_list(\@media_titles, $pages);
 423                        }
 424                }
 425
 426                @titles = @titles[($batch+1)..$#titles];
 427        }
 428        return;
 429}
 430
 431sub get_mw_mediafile_for_page_revision {
 432        # Name of the file on Wiki, with the prefix.
 433        my $filename = shift;
 434        my $timestamp = shift;
 435        my %mediafile;
 436
 437        # Search if on a media file with given timestamp exists on
 438        # MediaWiki. In that case download the file.
 439        my $query = {
 440                action => 'query',
 441                prop => 'imageinfo',
 442                titles => "File:${filename}",
 443                iistart => $timestamp,
 444                iiend => $timestamp,
 445                iiprop => 'timestamp|archivename|url',
 446                iilimit => 1
 447        };
 448        my $result = $mediawiki->api($query);
 449
 450        my ($fileid, $file) = each( %{$result->{query}->{pages}} );
 451        # If not defined it means there is no revision of the file for
 452        # given timestamp.
 453        if (defined($file->{imageinfo})) {
 454                $mediafile{title} = $filename;
 455
 456                my $fileinfo = pop(@{$file->{imageinfo}});
 457                $mediafile{timestamp} = $fileinfo->{timestamp};
 458                # Mediawiki::API's download function doesn't support https URLs
 459                # and can't download old versions of files.
 460                print STDERR "\tDownloading file $mediafile{title}, version $mediafile{timestamp}\n";
 461                $mediafile{content} = download_mw_mediafile($fileinfo->{url});
 462        }
 463        return %mediafile;
 464}
 465
 466sub download_mw_mediafile {
 467        my $download_url = shift;
 468
 469        my $response = $mediawiki->{ua}->get($download_url);
 470        if ($response->code == 200) {
 471                return $response->decoded_content;
 472        } else {
 473                print STDERR "Error downloading mediafile from :\n";
 474                print STDERR "URL: ${download_url}\n";
 475                print STDERR 'Server response: ' . $response->code . q{ } . $response->message . "\n";
 476                exit 1;
 477        }
 478}
 479
 480sub get_last_local_revision {
 481        # Get note regarding last mediawiki revision
 482        my $note = run_git("notes --ref=${remotename}/mediawiki show refs/mediawiki/${remotename}/master 2>/dev/null");
 483        my @note_info = split(/ /, $note);
 484
 485        my $lastrevision_number;
 486        if (!(defined($note_info[0]) && $note_info[0] eq 'mediawiki_revision:')) {
 487                print STDERR 'No previous mediawiki revision found';
 488                $lastrevision_number = 0;
 489        } else {
 490                # Notes are formatted : mediawiki_revision: #number
 491                $lastrevision_number = $note_info[1];
 492                chomp($lastrevision_number);
 493                print STDERR "Last local mediawiki revision found is ${lastrevision_number}";
 494        }
 495        return $lastrevision_number;
 496}
 497
 498# Get the last remote revision without taking in account which pages are
 499# tracked or not. This function makes a single request to the wiki thus
 500# avoid a loop onto all tracked pages. This is useful for the fetch-by-rev
 501# option.
 502sub get_last_global_remote_rev {
 503        mw_connect_maybe();
 504
 505        my $query = {
 506                action => 'query',
 507                list => 'recentchanges',
 508                prop => 'revisions',
 509                rclimit => '1',
 510                rcdir => 'older',
 511        };
 512        my $result = $mediawiki->api($query);
 513        return $result->{query}->{recentchanges}[0]->{revid};
 514}
 515
 516# Get the last remote revision concerning the tracked pages and the tracked
 517# categories.
 518sub get_last_remote_revision {
 519        mw_connect_maybe();
 520
 521        my %pages_hash = get_mw_pages();
 522        my @pages = values(%pages_hash);
 523
 524        my $max_rev_num = 0;
 525
 526        print STDERR "Getting last revision id on tracked pages...\n";
 527
 528        foreach my $page (@pages) {
 529                my $id = $page->{pageid};
 530
 531                my $query = {
 532                        action => 'query',
 533                        prop => 'revisions',
 534                        rvprop => 'ids|timestamp',
 535                        pageids => $id,
 536                };
 537
 538                my $result = $mediawiki->api($query);
 539
 540                my $lastrev = pop(@{$result->{query}->{pages}->{$id}->{revisions}});
 541
 542                $basetimestamps{$lastrev->{revid}} = $lastrev->{timestamp};
 543
 544                $max_rev_num = ($lastrev->{revid} > $max_rev_num ? $lastrev->{revid} : $max_rev_num);
 545        }
 546
 547        print STDERR "Last remote revision found is $max_rev_num.\n";
 548        return $max_rev_num;
 549}
 550
 551# Clean content before sending it to MediaWiki
 552sub mediawiki_clean {
 553        my $string = shift;
 554        my $page_created = shift;
 555        # Mediawiki does not allow blank space at the end of a page and ends with a single \n.
 556        # This function right trims a string and adds a \n at the end to follow this rule
 557        $string =~ s/\s+$//;
 558        if ($string eq "" && $page_created) {
 559                # Creating empty pages is forbidden.
 560                $string = EMPTY_CONTENT;
 561        }
 562        return $string."\n";
 563}
 564
 565# Filter applied on MediaWiki data before adding them to Git
 566sub mediawiki_smudge {
 567        my $string = shift;
 568        if ($string eq EMPTY_CONTENT) {
 569                $string = "";
 570        }
 571        # This \n is important. This is due to mediawiki's way to handle end of files.
 572        return "${string}\n";
 573}
 574
 575sub mediawiki_clean_filename {
 576        my $filename = shift;
 577        $filename =~ s{@{[SLASH_REPLACEMENT]}}{/}g;
 578        # [, ], |, {, and } are forbidden by MediaWiki, even URL-encoded.
 579        # Do a variant of URL-encoding, i.e. looks like URL-encoding,
 580        # but with _ added to prevent MediaWiki from thinking this is
 581        # an actual special character.
 582        $filename =~ s/[\[\]\{\}\|]/sprintf("_%%_%x", ord($&))/ge;
 583        # If we use the uri escape before
 584        # we should unescape here, before anything
 585
 586        return $filename;
 587}
 588
 589sub mediawiki_smudge_filename {
 590        my $filename = shift;
 591        $filename =~ s{/}{@{[SLASH_REPLACEMENT]}}g;
 592        $filename =~ s/ /_/g;
 593        # Decode forbidden characters encoded in mediawiki_clean_filename
 594        $filename =~ s/_%_([0-9a-fA-F][0-9a-fA-F])/sprintf('%c', hex($1))/ge;
 595        return $filename;
 596}
 597
 598sub literal_data {
 599        my ($content) = @_;
 600        print STDOUT 'data ', bytes::length($content), "\n", $content;
 601        return;
 602}
 603
 604sub literal_data_raw {
 605        # Output possibly binary content.
 606        my ($content) = @_;
 607        # Avoid confusion between size in bytes and in characters
 608        utf8::downgrade($content);
 609        binmode STDOUT, ':raw';
 610        print STDOUT 'data ', bytes::length($content), "\n", $content;
 611        binmode STDOUT, ':encoding(UTF-8)';
 612        return;
 613}
 614
 615sub mw_capabilities {
 616        # Revisions are imported to the private namespace
 617        # refs/mediawiki/$remotename/ by the helper and fetched into
 618        # refs/remotes/$remotename later by fetch.
 619        print STDOUT "refspec refs/heads/*:refs/mediawiki/${remotename}/*\n";
 620        print STDOUT "import\n";
 621        print STDOUT "list\n";
 622        print STDOUT "push\n";
 623        print STDOUT "\n";
 624        return;
 625}
 626
 627sub mw_list {
 628        # MediaWiki do not have branches, we consider one branch arbitrarily
 629        # called master, and HEAD pointing to it.
 630        print STDOUT "? refs/heads/master\n";
 631        print STDOUT "\@refs/heads/master HEAD\n";
 632        print STDOUT "\n";
 633        return;
 634}
 635
 636sub mw_option {
 637        print STDERR "remote-helper command 'option $_[0]' not yet implemented\n";
 638        print STDOUT "unsupported\n";
 639        return;
 640}
 641
 642sub fetch_mw_revisions_for_page {
 643        my $page = shift;
 644        my $id = shift;
 645        my $fetch_from = shift;
 646        my @page_revs = ();
 647        my $query = {
 648                action => 'query',
 649                prop => 'revisions',
 650                rvprop => 'ids',
 651                rvdir => 'newer',
 652                rvstartid => $fetch_from,
 653                rvlimit => 500,
 654                pageids => $id,
 655        };
 656
 657        my $revnum = 0;
 658        # Get 500 revisions at a time due to the mediawiki api limit
 659        while (1) {
 660                my $result = $mediawiki->api($query);
 661
 662                # Parse each of those 500 revisions
 663                foreach my $revision (@{$result->{query}->{pages}->{$id}->{revisions}}) {
 664                        my $page_rev_ids;
 665                        $page_rev_ids->{pageid} = $page->{pageid};
 666                        $page_rev_ids->{revid} = $revision->{revid};
 667                        push(@page_revs, $page_rev_ids);
 668                        $revnum++;
 669                }
 670                last unless $result->{'query-continue'};
 671                $query->{rvstartid} = $result->{'query-continue'}->{revisions}->{rvstartid};
 672        }
 673        if ($shallow_import && @page_revs) {
 674                print STDERR "  Found 1 revision (shallow import).\n";
 675                @page_revs = sort {$b->{revid} <=> $a->{revid}} (@page_revs);
 676                return $page_revs[0];
 677        }
 678        print STDERR "  Found ${revnum} revision(s).\n";
 679        return @page_revs;
 680}
 681
 682sub fetch_mw_revisions {
 683        my $pages = shift; my @pages = @{$pages};
 684        my $fetch_from = shift;
 685
 686        my @revisions = ();
 687        my $n = 1;
 688        foreach my $page (@pages) {
 689                my $id = $page->{pageid};
 690                print STDERR "page ${n}/", scalar(@pages), ': ', $page->{title}, "\n";
 691                $n++;
 692                my @page_revs = fetch_mw_revisions_for_page($page, $id, $fetch_from);
 693                @revisions = (@page_revs, @revisions);
 694        }
 695
 696        return ($n, @revisions);
 697}
 698
 699sub fe_escape_path {
 700    my $path = shift;
 701    $path =~ s/\\/\\\\/g;
 702    $path =~ s/"/\\"/g;
 703    $path =~ s/\n/\\n/g;
 704    return qq("${path}");
 705}
 706
 707sub import_file_revision {
 708        my $commit = shift;
 709        my %commit = %{$commit};
 710        my $full_import = shift;
 711        my $n = shift;
 712        my $mediafile = shift;
 713        my %mediafile;
 714        if ($mediafile) {
 715                %mediafile = %{$mediafile};
 716        }
 717
 718        my $title = $commit{title};
 719        my $comment = $commit{comment};
 720        my $content = $commit{content};
 721        my $author = $commit{author};
 722        my $date = $commit{date};
 723
 724        print STDOUT "commit refs/mediawiki/${remotename}/master\n";
 725        print STDOUT "mark :${n}\n";
 726        print STDOUT "committer ${author} <${author}\@${wiki_name}> " . $date->epoch . " +0000\n";
 727        literal_data($comment);
 728
 729        # If it's not a clone, we need to know where to start from
 730        if (!$full_import && $n == 1) {
 731                print STDOUT "from refs/mediawiki/${remotename}/master^0\n";
 732        }
 733        if ($content ne DELETED_CONTENT) {
 734                print STDOUT 'M 644 inline ' .
 735                    fe_escape_path("${title}.mw") . "\n";
 736                literal_data($content);
 737                if (%mediafile) {
 738                        print STDOUT 'M 644 inline '
 739                            . fe_escape_path($mediafile{title}) . "\n";
 740                        literal_data_raw($mediafile{content});
 741                }
 742                print STDOUT "\n\n";
 743        } else {
 744                print STDOUT 'D ' . fe_escape_path("${title}.mw") . "\n";
 745        }
 746
 747        # mediawiki revision number in the git note
 748        if ($full_import && $n == 1) {
 749                print STDOUT "reset refs/notes/${remotename}/mediawiki\n";
 750        }
 751        print STDOUT "commit refs/notes/${remotename}/mediawiki\n";
 752        print STDOUT "committer ${author} <${author}\@${wiki_name}> " . $date->epoch . " +0000\n";
 753        literal_data('Note added by git-mediawiki during import');
 754        if (!$full_import && $n == 1) {
 755                print STDOUT "from refs/notes/${remotename}/mediawiki^0\n";
 756        }
 757        print STDOUT "N inline :${n}\n";
 758        literal_data("mediawiki_revision: $commit{mw_revision}");
 759        print STDOUT "\n\n";
 760        return;
 761}
 762
 763# parse a sequence of
 764# <cmd> <arg1>
 765# <cmd> <arg2>
 766# \n
 767# (like batch sequence of import and sequence of push statements)
 768sub get_more_refs {
 769        my $cmd = shift;
 770        my @refs;
 771        while (1) {
 772                my $line = <STDIN>;
 773                if ($line =~ /^$cmd (.*)$/) {
 774                        push(@refs, $1);
 775                } elsif ($line eq "\n") {
 776                        return @refs;
 777                } else {
 778                        die("Invalid command in a '$cmd' batch: $_\n");
 779                }
 780        }
 781        return;
 782}
 783
 784sub mw_import {
 785        # multiple import commands can follow each other.
 786        my @refs = (shift, get_more_refs('import'));
 787        foreach my $ref (@refs) {
 788                mw_import_ref($ref);
 789        }
 790        print STDOUT "done\n";
 791        return;
 792}
 793
 794sub mw_import_ref {
 795        my $ref = shift;
 796        # The remote helper will call "import HEAD" and
 797        # "import refs/heads/master".
 798        # Since HEAD is a symbolic ref to master (by convention,
 799        # followed by the output of the command "list" that we gave),
 800        # we don't need to do anything in this case.
 801        if ($ref eq 'HEAD') {
 802                return;
 803        }
 804
 805        mw_connect_maybe();
 806
 807        print STDERR "Searching revisions...\n";
 808        my $last_local = get_last_local_revision();
 809        my $fetch_from = $last_local + 1;
 810        if ($fetch_from == 1) {
 811                print STDERR ", fetching from beginning.\n";
 812        } else {
 813                print STDERR ", fetching from here.\n";
 814        }
 815
 816        my $n = 0;
 817        if ($fetch_strategy eq 'by_rev') {
 818                print STDERR "Fetching & writing export data by revs...\n";
 819                $n = mw_import_ref_by_revs($fetch_from);
 820        } elsif ($fetch_strategy eq 'by_page') {
 821                print STDERR "Fetching & writing export data by pages...\n";
 822                $n = mw_import_ref_by_pages($fetch_from);
 823        } else {
 824                print STDERR qq(fatal: invalid fetch strategy "${fetch_strategy}".\n);
 825                print STDERR "Check your configuration variables remote.${remotename}.fetchStrategy and mediawiki.fetchStrategy\n";
 826                exit 1;
 827        }
 828
 829        if ($fetch_from == 1 && $n == 0) {
 830                print STDERR "You appear to have cloned an empty MediaWiki.\n";
 831                # Something has to be done remote-helper side. If nothing is done, an error is
 832                # thrown saying that HEAD is referring to unknown object 0000000000000000000
 833                # and the clone fails.
 834        }
 835        return;
 836}
 837
 838sub mw_import_ref_by_pages {
 839
 840        my $fetch_from = shift;
 841        my %pages_hash = get_mw_pages();
 842        my @pages = values(%pages_hash);
 843
 844        my ($n, @revisions) = fetch_mw_revisions(\@pages, $fetch_from);
 845
 846        @revisions = sort {$a->{revid} <=> $b->{revid}} @revisions;
 847        my @revision_ids = map { $_->{revid} } @revisions;
 848
 849        return mw_import_revids($fetch_from, \@revision_ids, \%pages_hash);
 850}
 851
 852sub mw_import_ref_by_revs {
 853
 854        my $fetch_from = shift;
 855        my %pages_hash = get_mw_pages();
 856
 857        my $last_remote = get_last_global_remote_rev();
 858        my @revision_ids = $fetch_from..$last_remote;
 859        return mw_import_revids($fetch_from, \@revision_ids, \%pages_hash);
 860}
 861
 862# Import revisions given in second argument (array of integers).
 863# Only pages appearing in the third argument (hash indexed by page titles)
 864# will be imported.
 865sub mw_import_revids {
 866        my $fetch_from = shift;
 867        my $revision_ids = shift;
 868        my $pages = shift;
 869
 870        my $n = 0;
 871        my $n_actual = 0;
 872        my $last_timestamp = 0; # Placeholer in case $rev->timestamp is undefined
 873
 874        foreach my $pagerevid (@$revision_ids) {
 875                # Count page even if we skip it, since we display
 876                # $n/$total and $total includes skipped pages.
 877                $n++;
 878
 879                # fetch the content of the pages
 880                my $query = {
 881                        action => 'query',
 882                        prop => 'revisions',
 883                        rvprop => 'content|timestamp|comment|user|ids',
 884                        revids => $pagerevid,
 885                };
 886
 887                my $result = $mediawiki->api($query);
 888
 889                if (!$result) {
 890                        die "Failed to retrieve modified page for revision $pagerevid\n";
 891                }
 892
 893                if (defined($result->{query}->{badrevids}->{$pagerevid})) {
 894                        # The revision id does not exist on the remote wiki.
 895                        next;
 896                }
 897
 898                if (!defined($result->{query}->{pages})) {
 899                        die "Invalid revision ${pagerevid}.\n";
 900                }
 901
 902                my @result_pages = values(%{$result->{query}->{pages}});
 903                my $result_page = $result_pages[0];
 904                my $rev = $result_pages[0]->{revisions}->[0];
 905
 906                my $page_title = $result_page->{title};
 907
 908                if (!exists($pages->{$page_title})) {
 909                        print STDERR "${n}/", scalar(@$revision_ids),
 910                                ": Skipping revision #$rev->{revid} of ${page_title}\n";
 911                        next;
 912                }
 913
 914                $n_actual++;
 915
 916                my %commit;
 917                $commit{author} = $rev->{user} || 'Anonymous';
 918                $commit{comment} = $rev->{comment} || EMPTY_MESSAGE;
 919                $commit{title} = mediawiki_smudge_filename($page_title);
 920                $commit{mw_revision} = $rev->{revid};
 921                $commit{content} = mediawiki_smudge($rev->{'*'});
 922
 923                if (!defined($rev->{timestamp})) {
 924                        $last_timestamp++;
 925                } else {
 926                        $last_timestamp = $rev->{timestamp};
 927                }
 928                $commit{date} = DateTime::Format::ISO8601->parse_datetime($last_timestamp);
 929
 930                # Differentiates classic pages and media files.
 931                my ($namespace, $filename) = $page_title =~ /^([^:]*):(.*)$/;
 932                my %mediafile;
 933                if ($namespace) {
 934                        my $id = get_mw_namespace_id($namespace);
 935                        if ($id && $id == get_mw_namespace_id('File')) {
 936                                %mediafile = get_mw_mediafile_for_page_revision($filename, $rev->{timestamp});
 937                        }
 938                }
 939                # If this is a revision of the media page for new version
 940                # of a file do one common commit for both file and media page.
 941                # Else do commit only for that page.
 942                print STDERR "${n}/", scalar(@$revision_ids), ": Revision #$rev->{revid} of $commit{title}\n";
 943                import_file_revision(\%commit, ($fetch_from == 1), $n_actual, \%mediafile);
 944        }
 945
 946        return $n_actual;
 947}
 948
 949sub error_non_fast_forward {
 950        my $advice = run_git('config --bool advice.pushNonFastForward');
 951        chomp($advice);
 952        if ($advice ne 'false') {
 953                # Native git-push would show this after the summary.
 954                # We can't ask it to display it cleanly, so print it
 955                # ourselves before.
 956                print STDERR "To prevent you from losing history, non-fast-forward updates were rejected\n";
 957                print STDERR "Merge the remote changes (e.g. 'git pull') before pushing again. See the\n";
 958                print STDERR "'Note about fast-forwards' section of 'git push --help' for details.\n";
 959        }
 960        print STDOUT qq(error $_[0] "non-fast-forward"\n);
 961        return 0;
 962}
 963
 964sub mw_upload_file {
 965        my $complete_file_name = shift;
 966        my $new_sha1 = shift;
 967        my $extension = shift;
 968        my $file_deleted = shift;
 969        my $summary = shift;
 970        my $newrevid;
 971        my $path = "File:${complete_file_name}";
 972        my %hashFiles = get_allowed_file_extensions();
 973        if (!exists($hashFiles{$extension})) {
 974                print STDERR "${complete_file_name} is not a permitted file on this wiki.\n";
 975                print STDERR "Check the configuration of file uploads in your mediawiki.\n";
 976                return $newrevid;
 977        }
 978        # Deleting and uploading a file requires a priviledged user
 979        if ($file_deleted) {
 980                mw_connect_maybe();
 981                my $query = {
 982                        action => 'delete',
 983                        title => $path,
 984                        reason => $summary
 985                };
 986                if (!$mediawiki->edit($query)) {
 987                        print STDERR "Failed to delete file on remote wiki\n";
 988                        print STDERR "Check your permissions on the remote site. Error code:\n";
 989                        print STDERR $mediawiki->{error}->{code} . ':' . $mediawiki->{error}->{details};
 990                        exit 1;
 991                }
 992        } else {
 993                # Don't let perl try to interpret file content as UTF-8 => use "raw"
 994                my $content = run_git("cat-file blob ${new_sha1}", 'raw');
 995                if ($content ne "") {
 996                        mw_connect_maybe();
 997                        $mediawiki->{config}->{upload_url} =
 998                                "${url}/index.php/Special:Upload";
 999                        $mediawiki->edit({
1000                                action => 'upload',
1001                                filename => $complete_file_name,
1002                                comment => $summary,
1003                                file => [undef,
1004                                         $complete_file_name,
1005                                         Content => $content],
1006                                ignorewarnings => 1,
1007                        }, {
1008                                skip_encoding => 1
1009                        } ) || die $mediawiki->{error}->{code} . ':'
1010                                 . $mediawiki->{error}->{details} . "\n";
1011                        my $last_file_page = $mediawiki->get_page({title => $path});
1012                        $newrevid = $last_file_page->{revid};
1013                        print STDERR "Pushed file: ${new_sha1} - ${complete_file_name}.\n";
1014                } else {
1015                        print STDERR "Empty file ${complete_file_name} not pushed.\n";
1016                }
1017        }
1018        return $newrevid;
1019}
1020
1021sub mw_push_file {
1022        my $diff_info = shift;
1023        # $diff_info contains a string in this format:
1024        # 100644 100644 <sha1_of_blob_before_commit> <sha1_of_blob_now> <status>
1025        my @diff_info_split = split(/[ \t]/, $diff_info);
1026
1027        # Filename, including .mw extension
1028        my $complete_file_name = shift;
1029        # Commit message
1030        my $summary = shift;
1031        # MediaWiki revision number. Keep the previous one by default,
1032        # in case there's no edit to perform.
1033        my $oldrevid = shift;
1034        my $newrevid;
1035
1036        if ($summary eq EMPTY_MESSAGE) {
1037                $summary = '';
1038        }
1039
1040        my $new_sha1 = $diff_info_split[3];
1041        my $old_sha1 = $diff_info_split[2];
1042        my $page_created = ($old_sha1 eq NULL_SHA1);
1043        my $page_deleted = ($new_sha1 eq NULL_SHA1);
1044        $complete_file_name = mediawiki_clean_filename($complete_file_name);
1045
1046        my ($title, $extension) = $complete_file_name =~ /^(.*)\.([^\.]*)$/;
1047        if (!defined($extension)) {
1048                $extension = "";
1049        }
1050        if ($extension eq 'mw') {
1051                my $ns = get_mw_namespace_id_for_page($complete_file_name);
1052                if ($ns && $ns == get_mw_namespace_id('File') && (!$export_media)) {
1053                        print STDERR "Ignoring media file related page: ${complete_file_name}\n";
1054                        return ($oldrevid, 'ok');
1055                }
1056                my $file_content;
1057                if ($page_deleted) {
1058                        # Deleting a page usually requires
1059                        # special privileges. A common
1060                        # convention is to replace the page
1061                        # with this content instead:
1062                        $file_content = DELETED_CONTENT;
1063                } else {
1064                        $file_content = run_git("cat-file blob ${new_sha1}");
1065                }
1066
1067                mw_connect_maybe();
1068
1069                my $result = $mediawiki->edit( {
1070                        action => 'edit',
1071                        summary => $summary,
1072                        title => $title,
1073                        basetimestamp => $basetimestamps{$oldrevid},
1074                        text => mediawiki_clean($file_content, $page_created),
1075                                  }, {
1076                                          skip_encoding => 1 # Helps with names with accentuated characters
1077                                  });
1078                if (!$result) {
1079                        if ($mediawiki->{error}->{code} == 3) {
1080                                # edit conflicts, considered as non-fast-forward
1081                                print STDERR 'Warning: Error ' .
1082                                    $mediawiki->{error}->{code} .
1083                                    ' from mediwiki: ' . $mediawiki->{error}->{details} .
1084                                    ".\n";
1085                                return ($oldrevid, 'non-fast-forward');
1086                        } else {
1087                                # Other errors. Shouldn't happen => just die()
1088                                die 'Fatal: Error ' .
1089                                    $mediawiki->{error}->{code} .
1090                                    ' from mediwiki: ' . $mediawiki->{error}->{details} . "\n";
1091                        }
1092                }
1093                $newrevid = $result->{edit}->{newrevid};
1094                print STDERR "Pushed file: ${new_sha1} - ${title}\n";
1095        } elsif ($export_media) {
1096                $newrevid = mw_upload_file($complete_file_name, $new_sha1,
1097                                           $extension, $page_deleted,
1098                                           $summary);
1099        } else {
1100                print STDERR "Ignoring media file ${title}\n";
1101        }
1102        $newrevid = ($newrevid or $oldrevid);
1103        return ($newrevid, 'ok');
1104}
1105
1106sub mw_push {
1107        # multiple push statements can follow each other
1108        my @refsspecs = (shift, get_more_refs('push'));
1109        my $pushed;
1110        for my $refspec (@refsspecs) {
1111                my ($force, $local, $remote) = $refspec =~ /^(\+)?([^:]*):([^:]*)$/
1112                    or die("Invalid refspec for push. Expected <src>:<dst> or +<src>:<dst>\n");
1113                if ($force) {
1114                        print STDERR "Warning: forced push not allowed on a MediaWiki.\n";
1115                }
1116                if ($local eq "") {
1117                        print STDERR "Cannot delete remote branch on a MediaWiki\n";
1118                        print STDOUT "error ${remote} cannot delete\n";
1119                        next;
1120                }
1121                if ($remote ne 'refs/heads/master') {
1122                        print STDERR "Only push to the branch 'master' is supported on a MediaWiki\n";
1123                        print STDOUT "error ${remote} only master allowed\n";
1124                        next;
1125                }
1126                if (mw_push_revision($local, $remote)) {
1127                        $pushed = 1;
1128                }
1129        }
1130
1131        # Notify Git that the push is done
1132        print STDOUT "\n";
1133
1134        if ($pushed && $dumb_push) {
1135                print STDERR "Just pushed some revisions to MediaWiki.\n";
1136                print STDERR "The pushed revisions now have to be re-imported, and your current branch\n";
1137                print STDERR "needs to be updated with these re-imported commits. You can do this with\n";
1138                print STDERR "\n";
1139                print STDERR "  git pull --rebase\n";
1140                print STDERR "\n";
1141        }
1142        return;
1143}
1144
1145sub mw_push_revision {
1146        my $local = shift;
1147        my $remote = shift; # actually, this has to be "refs/heads/master" at this point.
1148        my $last_local_revid = get_last_local_revision();
1149        print STDERR ".\n"; # Finish sentence started by get_last_local_revision()
1150        my $last_remote_revid = get_last_remote_revision();
1151        my $mw_revision = $last_remote_revid;
1152
1153        # Get sha1 of commit pointed by local HEAD
1154        my $HEAD_sha1 = run_git("rev-parse ${local} 2>/dev/null");
1155        chomp($HEAD_sha1);
1156        # Get sha1 of commit pointed by remotes/$remotename/master
1157        my $remoteorigin_sha1 = run_git("rev-parse refs/remotes/${remotename}/master 2>/dev/null");
1158        chomp($remoteorigin_sha1);
1159
1160        if ($last_local_revid > 0 &&
1161            $last_local_revid < $last_remote_revid) {
1162                return error_non_fast_forward($remote);
1163        }
1164
1165        if ($HEAD_sha1 eq $remoteorigin_sha1) {
1166                # nothing to push
1167                return 0;
1168        }
1169
1170        # Get every commit in between HEAD and refs/remotes/origin/master,
1171        # including HEAD and refs/remotes/origin/master
1172        my @commit_pairs = ();
1173        if ($last_local_revid > 0) {
1174                my $parsed_sha1 = $remoteorigin_sha1;
1175                # Find a path from last MediaWiki commit to pushed commit
1176                print STDERR "Computing path from local to remote ...\n";
1177                my @local_ancestry = split(/\n/, run_git("rev-list --boundary --parents ${local} ^${parsed_sha1}"));
1178                my %local_ancestry;
1179                foreach my $line (@local_ancestry) {
1180                        if (my ($child, $parents) = $line =~ /^-?([a-f0-9]+) ([a-f0-9 ]+)/) {
1181                                foreach my $parent (split(/ /, $parents)) {
1182                                        $local_ancestry{$parent} = $child;
1183                                }
1184                        } elsif (!$line =~ /^([a-f0-9]+)/) {
1185                                die "Unexpected output from git rev-list: ${line}\n";
1186                        }
1187                }
1188                while ($parsed_sha1 ne $HEAD_sha1) {
1189                        my $child = $local_ancestry{$parsed_sha1};
1190                        if (!$child) {
1191                                printf STDERR "Cannot find a path in history from remote commit to last commit\n";
1192                                return error_non_fast_forward($remote);
1193                        }
1194                        push(@commit_pairs, [$parsed_sha1, $child]);
1195                        $parsed_sha1 = $child;
1196                }
1197        } else {
1198                # No remote mediawiki revision. Export the whole
1199                # history (linearized with --first-parent)
1200                print STDERR "Warning: no common ancestor, pushing complete history\n";
1201                my $history = run_git("rev-list --first-parent --children ${local}");
1202                my @history = split(/\n/, $history);
1203                @history = @history[1..$#history];
1204                foreach my $line (reverse @history) {
1205                        my @commit_info_split = split(/[ \n]/, $line);
1206                        push(@commit_pairs, \@commit_info_split);
1207                }
1208        }
1209
1210        foreach my $commit_info_split (@commit_pairs) {
1211                my $sha1_child = @{$commit_info_split}[0];
1212                my $sha1_commit = @{$commit_info_split}[1];
1213                my $diff_infos = run_git("diff-tree -r --raw -z ${sha1_child} ${sha1_commit}");
1214                # TODO: we could detect rename, and encode them with a #redirect on the wiki.
1215                # TODO: for now, it's just a delete+add
1216                my @diff_info_list = split(/\0/, $diff_infos);
1217                # Keep the subject line of the commit message as mediawiki comment for the revision
1218                my $commit_msg = run_git(qq(log --no-walk --format="%s" ${sha1_commit}));
1219                chomp($commit_msg);
1220                # Push every blob
1221                while (@diff_info_list) {
1222                        my $status;
1223                        # git diff-tree -z gives an output like
1224                        # <metadata>\0<filename1>\0
1225                        # <metadata>\0<filename2>\0
1226                        # and we've split on \0.
1227                        my $info = shift(@diff_info_list);
1228                        my $file = shift(@diff_info_list);
1229                        ($mw_revision, $status) = mw_push_file($info, $file, $commit_msg, $mw_revision);
1230                        if ($status eq 'non-fast-forward') {
1231                                # we may already have sent part of the
1232                                # commit to MediaWiki, but it's too
1233                                # late to cancel it. Stop the push in
1234                                # the middle, but still give an
1235                                # accurate error message.
1236                                return error_non_fast_forward($remote);
1237                        }
1238                        if ($status ne 'ok') {
1239                                die("Unknown error from mw_push_file()\n");
1240                        }
1241                }
1242                unless ($dumb_push) {
1243                        run_git(qq(notes --ref=${remotename}/mediawiki add -f -m "mediawiki_revision: ${mw_revision}" ${sha1_commit}));
1244                        run_git(qq(update-ref -m "Git-MediaWiki push" refs/mediawiki/${remotename}/master ${sha1_commit} ${sha1_child}));
1245                }
1246        }
1247
1248        print STDOUT "ok ${remote}\n";
1249        return 1;
1250}
1251
1252sub get_allowed_file_extensions {
1253        mw_connect_maybe();
1254
1255        my $query = {
1256                action => 'query',
1257                meta => 'siteinfo',
1258                siprop => 'fileextensions'
1259                };
1260        my $result = $mediawiki->api($query);
1261        my @file_extensions = map { $_->{ext}} @{$result->{query}->{fileextensions}};
1262        my %hashFile = map { $_ => 1 } @file_extensions;
1263
1264        return %hashFile;
1265}
1266
1267# In memory cache for MediaWiki namespace ids.
1268my %namespace_id;
1269
1270# Namespaces whose id is cached in the configuration file
1271# (to avoid duplicates)
1272my %cached_mw_namespace_id;
1273
1274# Return MediaWiki id for a canonical namespace name.
1275# Ex.: "File", "Project".
1276sub get_mw_namespace_id {
1277        mw_connect_maybe();
1278        my $name = shift;
1279
1280        if (!exists $namespace_id{$name}) {
1281                # Look at configuration file, if the record for that namespace is
1282                # already cached. Namespaces are stored in form:
1283                # "Name_of_namespace:Id_namespace", ex.: "File:6".
1284                my @temp = split(/\n/,
1285                                 run_git("config --get-all remote.${remotename}.namespaceCache"));
1286                chomp(@temp);
1287                foreach my $ns (@temp) {
1288                        my ($n, $id) = split(/:/, $ns);
1289                        if ($id eq 'notANameSpace') {
1290                                $namespace_id{$n} = {is_namespace => 0};
1291                        } else {
1292                                $namespace_id{$n} = {is_namespace => 1, id => $id};
1293                        }
1294                        $cached_mw_namespace_id{$n} = 1;
1295                }
1296        }
1297
1298        if (!exists $namespace_id{$name}) {
1299                print STDERR "Namespace ${name} not found in cache, querying the wiki ...\n";
1300                # NS not found => get namespace id from MW and store it in
1301                # configuration file.
1302                my $query = {
1303                        action => 'query',
1304                        meta => 'siteinfo',
1305                        siprop => 'namespaces'
1306                };
1307                my $result = $mediawiki->api($query);
1308
1309                while (my ($id, $ns) = each(%{$result->{query}->{namespaces}})) {
1310                        if (defined($ns->{id}) && defined($ns->{canonical})) {
1311                                $namespace_id{$ns->{canonical}} = {is_namespace => 1, id => $ns->{id}};
1312                                if ($ns->{'*'}) {
1313                                        # alias (e.g. french Fichier: as alias for canonical File:)
1314                                        $namespace_id{$ns->{'*'}} = {is_namespace => 1, id => $ns->{id}};
1315                                }
1316                        }
1317                }
1318        }
1319
1320        my $ns = $namespace_id{$name};
1321        my $id;
1322
1323        unless (defined $ns) {
1324                print STDERR "No such namespace ${name} on MediaWiki.\n";
1325                $ns = {is_namespace => 0};
1326                $namespace_id{$name} = $ns;
1327        }
1328
1329        if ($ns->{is_namespace}) {
1330                $id = $ns->{id};
1331        }
1332
1333        # Store "notANameSpace" as special value for inexisting namespaces
1334        my $store_id = ($id || 'notANameSpace');
1335
1336        # Store explicitely requested namespaces on disk
1337        if (!exists $cached_mw_namespace_id{$name}) {
1338                run_git(qq(config --add remote.${remotename}.namespaceCache "${name}:${store_id}"));
1339                $cached_mw_namespace_id{$name} = 1;
1340        }
1341        return $id;
1342}
1343
1344sub get_mw_namespace_id_for_page {
1345        my $namespace = shift;
1346        if ($namespace =~ /^([^:]*):/) {
1347                return get_mw_namespace_id($namespace);
1348        } else {
1349                return;
1350        }
1351}