Andrew's git - gitweb.git/blob

29fb614888f92bfb80465b7dc37ddaa0541d651a
   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;
  25use IPC::Open2;
  26
  27# Mediawiki filenames can contain forward slashes. This variable decides by which pattern they should be replaced
  28use constant SLASH_REPLACEMENT => "%2F";
  29
  30# It's not always possible to delete pages (may require some
  31# privileges). Deleted pages are replaced with this content.
  32use constant DELETED_CONTENT => "[[Category:Deleted]]\n";
  33
  34# It's not possible to create empty pages. New empty files in Git are
  35# sent with this content instead.
  36use constant EMPTY_CONTENT => "<!-- empty page -->\n";
  37
  38# used to reflect file creation or deletion in diff.
  39use constant NULL_SHA1 => "0000000000000000000000000000000000000000";
  40
  41# Used on Git's side to reflect empty edit messages on the wiki
  42use constant EMPTY_MESSAGE => '*Empty MediaWiki Message*';
  43
  44my $remotename = $ARGV[0];
  45my $url = $ARGV[1];
  46
  47# Accept both space-separated and multiple keys in config file.
  48# Spaces should be written as _ anyway because we'll use chomp.
  49my @tracked_pages = split(/[ \n]/, run_git("config --get-all remote.". $remotename .".pages"));
  50chomp(@tracked_pages);
  51
  52# Just like @tracked_pages, but for MediaWiki categories.
  53my @tracked_categories = split(/[ \n]/, run_git("config --get-all remote.". $remotename .".categories"));
  54chomp(@tracked_categories);
  55
  56# Import media files on pull
  57my $import_media = run_git("config --get --bool remote.". $remotename .".mediaimport");
  58chomp($import_media);
  59$import_media = ($import_media eq "true");
  60
  61# Export media files on push
  62my $export_media = run_git("config --get --bool remote.". $remotename .".mediaexport");
  63chomp($export_media);
  64$export_media = !($export_media eq "false");
  65
  66my $wiki_login = run_git("config --get remote.". $remotename .".mwLogin");
  67# Note: mwPassword is discourraged. Use the credential system instead.
  68my $wiki_passwd = run_git("config --get remote.". $remotename .".mwPassword");
  69my $wiki_domain = run_git("config --get remote.". $remotename .".mwDomain");
  70chomp($wiki_login);
  71chomp($wiki_passwd);
  72chomp($wiki_domain);
  73
  74# Import only last revisions (both for clone and fetch)
  75my $shallow_import = run_git("config --get --bool remote.". $remotename .".shallow");
  76chomp($shallow_import);
  77$shallow_import = ($shallow_import eq "true");
  78
  79# Fetch (clone and pull) by revisions instead of by pages. This behavior
  80# is more efficient when we have a wiki with lots of pages and we fetch
  81# the revisions quite often so that they concern only few pages.
  82# Possible values:
  83# - by_rev: perform one query per new revision on the remote wiki
  84# - by_page: query each tracked page for new revision
  85my $fetch_strategy = run_git("config --get remote.$remotename.fetchStrategy");
  86unless ($fetch_strategy) {
  87        $fetch_strategy = run_git("config --get mediawiki.fetchStrategy");
  88}
  89chomp($fetch_strategy);
  90unless ($fetch_strategy) {
  91        $fetch_strategy = "by_page";
  92}
  93
  94# Remember the timestamp corresponding to a revision id.
  95my %basetimestamps;
  96
  97# Dumb push: don't update notes and mediawiki ref to reflect the last push.
  98#
  99# Configurable with mediawiki.dumbPush, or per-remote with
 100# remote.<remotename>.dumbPush.
 101#
 102# This means the user will have to re-import the just-pushed
 103# revisions. On the other hand, this means that the Git revisions
 104# corresponding to MediaWiki revisions are all imported from the wiki,
 105# regardless of whether they were initially created in Git or from the
 106# web interface, hence all users will get the same history (i.e. if
 107# the push from Git to MediaWiki loses some information, everybody
 108# will get the history with information lost). If the import is
 109# deterministic, this means everybody gets the same sha1 for each
 110# MediaWiki revision.
 111my $dumb_push = run_git("config --get --bool remote.$remotename.dumbPush");
 112unless ($dumb_push) {
 113        $dumb_push = run_git("config --get --bool mediawiki.dumbPush");
 114}
 115chomp($dumb_push);
 116$dumb_push = ($dumb_push eq "true");
 117
 118my $wiki_name = $url;
 119$wiki_name =~ s{[^/]*://}{};
 120# If URL is like http://user:password@example.com/, we clearly don't
 121# want the password in $wiki_name. While we're there, also remove user
 122# and '@' sign, to avoid author like MWUser@HTTPUser@host.com
 123$wiki_name =~ s/^.*@//;
 124
 125# Commands parser
 126my @cmd;
 127while (<STDIN>) {
 128        chomp;
 129        @cmd = split(/ /);
 130        if (defined($cmd[0])) {
 131                # Line not blank
 132                if ($cmd[0] eq "capabilities") {
 133                        die("Too many arguments for capabilities\n") if (defined($cmd[1]));
 134                        mw_capabilities();
 135                } elsif ($cmd[0] eq "list") {
 136                        die("Too many arguments for list\n") if (defined($cmd[2]));
 137                        mw_list($cmd[1]);
 138                } elsif ($cmd[0] eq "import") {
 139                        die("Invalid arguments for import\n") if ($cmd[1] eq "" || defined($cmd[2]));
 140                        mw_import($cmd[1]);
 141                } elsif ($cmd[0] eq "option") {
 142                        die("Too many arguments for option\n") if ($cmd[1] eq "" || $cmd[2] eq "" || defined($cmd[3]));
 143                        mw_option($cmd[1],$cmd[2]);
 144                } elsif ($cmd[0] eq "push") {
 145                        mw_push($cmd[1]);
 146                } else {
 147                        print STDERR "Unknown command. Aborting...\n";
 148                        last;
 149                }
 150        } else {
 151                # blank line: we should terminate
 152                last;
 153        }
 154
 155        BEGIN { $| = 1 } # flush STDOUT, to make sure the previous
 156                         # command is fully processed.
 157}
 158
 159########################## Functions ##############################
 160
 161# MediaWiki API instance, created lazily.
 162my $mediawiki;
 163
 164sub mw_connect_maybe {
 165        if ($mediawiki) {
 166                return;
 167        }
 168        $mediawiki = MediaWiki::API->new;
 169        $mediawiki->{config}->{api_url} = "$url/api.php";
 170        if ($wiki_login) {
 171                my %credential = (
 172                        'url' => $url,
 173                        'username' => $wiki_login,
 174                        'password' => $wiki_passwd
 175                );
 176                Git::credential(\%credential);
 177                my $request = {lgname => $credential{username},
 178                               lgpassword => $credential{password},
 179                               lgdomain => $wiki_domain};
 180                if ($mediawiki->login($request)) {
 181                        Git::credential(\%credential, 'approve');
 182                        print STDERR "Logged in mediawiki user \"$credential{username}\".\n";
 183                } else {
 184                        print STDERR "Failed to log in mediawiki user \"$credential{username}\" on $url\n";
 185                        print STDERR "  (error " .
 186                                $mediawiki->{error}->{code} . ': ' .
 187                                $mediawiki->{error}->{details} . ")\n";
 188                        Git::credential(\%credential, 'reject');
 189                        exit 1;
 190                }
 191        }
 192        return;
 193}
 194
 195sub fatal_mw_error {
 196        my $action = shift;
 197        print STDERR "fatal: could not $action.\n";
 198        print STDERR "fatal: '$url' does not appear to be a mediawiki\n";
 199        if ($url =~ /^https/) {
 200                print STDERR "fatal: make sure '$url/api.php' is a valid page\n";
 201                print STDERR "fatal: and the SSL certificate is correct.\n";
 202        } else {
 203                print STDERR "fatal: make sure '$url/api.php' is a valid page.\n";
 204        }
 205        print STDERR "fatal: (error " .
 206            $mediawiki->{error}->{code} . ': ' .
 207            $mediawiki->{error}->{details} . ")\n";
 208        exit 1;
 209}
 210
 211## Functions for listing pages on the remote wiki
 212sub get_mw_tracked_pages {
 213        my $pages = shift;
 214        get_mw_page_list(\@tracked_pages, $pages);
 215        return;
 216}
 217
 218sub get_mw_page_list {
 219        my $page_list = shift;
 220        my $pages = shift;
 221        my @some_pages = @$page_list;
 222        while (@some_pages) {
 223                my $last_page = 50;
 224                if ($#some_pages < $last_page) {
 225                        $last_page = $#some_pages;
 226                }
 227                my @slice = @some_pages[0..$last_page];
 228                get_mw_first_pages(\@slice, $pages);
 229                @some_pages = @some_pages[51..$#some_pages];
 230        }
 231        return;
 232}
 233
 234sub get_mw_tracked_categories {
 235        my $pages = shift;
 236        foreach my $category (@tracked_categories) {
 237                if (index($category, ':') < 0) {
 238                        # Mediawiki requires the Category
 239                        # prefix, but let's not force the user
 240                        # to specify it.
 241                        $category = "Category:" . $category;
 242                }
 243                my $mw_pages = $mediawiki->list( {
 244                        action => 'query',
 245                        list => 'categorymembers',
 246                        cmtitle => $category,
 247                        cmlimit => 'max' } )
 248                        || die $mediawiki->{error}->{code} . ': '
 249                                . $mediawiki->{error}->{details} . "\n";
 250                foreach my $page (@{$mw_pages}) {
 251                        $pages->{$page->{title}} = $page;
 252                }
 253        }
 254        return;
 255}
 256
 257sub get_mw_all_pages {
 258        my $pages = shift;
 259        # No user-provided list, get the list of pages from the API.
 260        my $mw_pages = $mediawiki->list({
 261                action => 'query',
 262                list => 'allpages',
 263                aplimit => 'max'
 264        });
 265        if (!defined($mw_pages)) {
 266                fatal_mw_error("get the list of wiki pages");
 267        }
 268        foreach my $page (@{$mw_pages}) {
 269                $pages->{$page->{title}} = $page;
 270        }
 271        return;
 272}
 273
 274# queries the wiki for a set of pages. Meant to be used within a loop
 275# querying the wiki for slices of page list.
 276sub get_mw_first_pages {
 277        my $some_pages = shift;
 278        my @some_pages = @{$some_pages};
 279
 280        my $pages = shift;
 281
 282        # pattern 'page1|page2|...' required by the API
 283        my $titles = join('|', @some_pages);
 284
 285        my $mw_pages = $mediawiki->api({
 286                action => 'query',
 287                titles => $titles,
 288        });
 289        if (!defined($mw_pages)) {
 290                fatal_mw_error("query the list of wiki pages");
 291        }
 292        while (my ($id, $page) = each(%{$mw_pages->{query}->{pages}})) {
 293                if ($id < 0) {
 294                        print STDERR "Warning: page $page->{title} not found on wiki\n";
 295                } else {
 296                        $pages->{$page->{title}} = $page;
 297                }
 298        }
 299        return;
 300}
 301
 302# Get the list of pages to be fetched according to configuration.
 303sub get_mw_pages {
 304        mw_connect_maybe();
 305
 306        print STDERR "Listing pages on remote wiki...\n";
 307
 308        my %pages; # hash on page titles to avoid duplicates
 309        my $user_defined;
 310        if (@tracked_pages) {
 311                $user_defined = 1;
 312                # The user provided a list of pages titles, but we
 313                # still need to query the API to get the page IDs.
 314                get_mw_tracked_pages(\%pages);
 315        }
 316        if (@tracked_categories) {
 317                $user_defined = 1;
 318                get_mw_tracked_categories(\%pages);
 319        }
 320        if (!$user_defined) {
 321                get_mw_all_pages(\%pages);
 322        }
 323        if ($import_media) {
 324                print STDERR "Getting media files for selected pages...\n";
 325                if ($user_defined) {
 326                        get_linked_mediafiles(\%pages);
 327                } else {
 328                        get_all_mediafiles(\%pages);
 329                }
 330        }
 331        print STDERR (scalar keys %pages) . " pages found.\n";
 332        return %pages;
 333}
 334
 335# usage: $out = run_git("command args");
 336#        $out = run_git("command args", "raw"); # don't interpret output as UTF-8.
 337sub run_git {
 338        my $args = shift;
 339        my $encoding = (shift || "encoding(UTF-8)");
 340        open(my $git, "-|:$encoding", "git " . $args);
 341        my $res = do { local $/; <$git> };
 342        close($git);
 343
 344        return $res;
 345}
 346
 347
 348sub get_all_mediafiles {
 349        my $pages = shift;
 350        # Attach list of all pages for media files from the API,
 351        # they are in a different namespace, only one namespace
 352        # can be queried at the same moment
 353        my $mw_pages = $mediawiki->list({
 354                action => 'query',
 355                list => 'allpages',
 356                apnamespace => get_mw_namespace_id("File"),
 357                aplimit => 'max'
 358        });
 359        if (!defined($mw_pages)) {
 360                print STDERR "fatal: could not get the list of pages for media files.\n";
 361                print STDERR "fatal: '$url' does not appear to be a mediawiki\n";
 362                print STDERR "fatal: make sure '$url/api.php' is a valid page.\n";
 363                exit 1;
 364        }
 365        foreach my $page (@{$mw_pages}) {
 366                $pages->{$page->{title}} = $page;
 367        }
 368        return;
 369}
 370
 371sub get_linked_mediafiles {
 372        my $pages = shift;
 373        my @titles = map { $_->{title} } values(%{$pages});
 374
 375        # The query is split in small batches because of the MW API limit of
 376        # the number of links to be returned (500 links max).
 377        my $batch = 10;
 378        while (@titles) {
 379                if ($#titles < $batch) {
 380                        $batch = $#titles;
 381                }
 382                my @slice = @titles[0..$batch];
 383
 384                # pattern 'page1|page2|...' required by the API
 385                my $mw_titles = join('|', @slice);
 386
 387                # Media files could be included or linked from
 388                # a page, get all related
 389                my $query = {
 390                        action => 'query',
 391                        prop => 'links|images',
 392                        titles => $mw_titles,
 393                        plnamespace => get_mw_namespace_id("File"),
 394                        pllimit => 'max'
 395                };
 396                my $result = $mediawiki->api($query);
 397
 398                while (my ($id, $page) = each(%{$result->{query}->{pages}})) {
 399                        my @media_titles;
 400                        if (defined($page->{links})) {
 401                                my @link_titles
 402                                    = map { $_->{title} } @{$page->{links}};
 403                                push(@media_titles, @link_titles);
 404                        }
 405                        if (defined($page->{images})) {
 406                                my @image_titles
 407                                    = map { $_->{title} } @{$page->{images}};
 408                                push(@media_titles, @image_titles);
 409                        }
 410                        if (@media_titles) {
 411                                get_mw_page_list(\@media_titles, $pages);
 412                        }
 413                }
 414
 415                @titles = @titles[($batch+1)..$#titles];
 416        }
 417        return;
 418}
 419
 420sub get_mw_mediafile_for_page_revision {
 421        # Name of the file on Wiki, with the prefix.
 422        my $filename = shift;
 423        my $timestamp = shift;
 424        my %mediafile;
 425
 426        # Search if on a media file with given timestamp exists on
 427        # MediaWiki. In that case download the file.
 428        my $query = {
 429                action => 'query',
 430                prop => 'imageinfo',
 431                titles => "File:" . $filename,
 432                iistart => $timestamp,
 433                iiend => $timestamp,
 434                iiprop => 'timestamp|archivename|url',
 435                iilimit => 1
 436        };
 437        my $result = $mediawiki->api($query);
 438
 439        my ($fileid, $file) = each( %{$result->{query}->{pages}} );
 440        # If not defined it means there is no revision of the file for
 441        # given timestamp.
 442        if (defined($file->{imageinfo})) {
 443                $mediafile{title} = $filename;
 444
 445                my $fileinfo = pop(@{$file->{imageinfo}});
 446                $mediafile{timestamp} = $fileinfo->{timestamp};
 447                # Mediawiki::API's download function doesn't support https URLs
 448                # and can't download old versions of files.
 449                print STDERR "\tDownloading file $mediafile{title}, version $mediafile{timestamp}\n";
 450                $mediafile{content} = download_mw_mediafile($fileinfo->{url});
 451        }
 452        return %mediafile;
 453}
 454
 455sub download_mw_mediafile {
 456        my $download_url = shift;
 457
 458        my $response = $mediawiki->{ua}->get($download_url);
 459        if ($response->code == 200) {
 460                return $response->decoded_content;
 461        } else {
 462                print STDERR "Error downloading mediafile from :\n";
 463                print STDERR "URL: $download_url\n";
 464                print STDERR "Server response: " . $response->code . " " . $response->message . "\n";
 465                exit 1;
 466        }
 467}
 468
 469sub get_last_local_revision {
 470        # Get note regarding last mediawiki revision
 471        my $note = run_git("notes --ref=$remotename/mediawiki show refs/mediawiki/$remotename/master 2>/dev/null");
 472        my @note_info = split(/ /, $note);
 473
 474        my $lastrevision_number;
 475        if (!(defined($note_info[0]) && $note_info[0] eq "mediawiki_revision:")) {
 476                print STDERR "No previous mediawiki revision found";
 477                $lastrevision_number = 0;
 478        } else {
 479                # Notes are formatted : mediawiki_revision: #number
 480                $lastrevision_number = $note_info[1];
 481                chomp($lastrevision_number);
 482                print STDERR "Last local mediawiki revision found is $lastrevision_number";
 483        }
 484        return $lastrevision_number;
 485}
 486
 487# Get the last remote revision without taking in account which pages are
 488# tracked or not. This function makes a single request to the wiki thus
 489# avoid a loop onto all tracked pages. This is useful for the fetch-by-rev
 490# option.
 491sub get_last_global_remote_rev {
 492        mw_connect_maybe();
 493
 494        my $query = {
 495                action => 'query',
 496                list => 'recentchanges',
 497                prop => 'revisions',
 498                rclimit => '1',
 499                rcdir => 'older',
 500        };
 501        my $result = $mediawiki->api($query);
 502        return $result->{query}->{recentchanges}[0]->{revid};
 503}
 504
 505# Get the last remote revision concerning the tracked pages and the tracked
 506# categories.
 507sub get_last_remote_revision {
 508        mw_connect_maybe();
 509
 510        my %pages_hash = get_mw_pages();
 511        my @pages = values(%pages_hash);
 512
 513        my $max_rev_num = 0;
 514
 515        print STDERR "Getting last revision id on tracked pages...\n";
 516
 517        foreach my $page (@pages) {
 518                my $id = $page->{pageid};
 519
 520                my $query = {
 521                        action => 'query',
 522                        prop => 'revisions',
 523                        rvprop => 'ids|timestamp',
 524                        pageids => $id,
 525                };
 526
 527                my $result = $mediawiki->api($query);
 528
 529                my $lastrev = pop(@{$result->{query}->{pages}->{$id}->{revisions}});
 530
 531                $basetimestamps{$lastrev->{revid}} = $lastrev->{timestamp};
 532
 533                $max_rev_num = ($lastrev->{revid} > $max_rev_num ? $lastrev->{revid} : $max_rev_num);
 534        }
 535
 536        print STDERR "Last remote revision found is $max_rev_num.\n";
 537        return $max_rev_num;
 538}
 539
 540# Clean content before sending it to MediaWiki
 541sub mediawiki_clean {
 542        my $string = shift;
 543        my $page_created = shift;
 544        # Mediawiki does not allow blank space at the end of a page and ends with a single \n.
 545        # This function right trims a string and adds a \n at the end to follow this rule
 546        $string =~ s/\s+$//;
 547        if ($string eq "" && $page_created) {
 548                # Creating empty pages is forbidden.
 549                $string = EMPTY_CONTENT;
 550        }
 551        return $string."\n";
 552}
 553
 554# Filter applied on MediaWiki data before adding them to Git
 555sub mediawiki_smudge {
 556        my $string = shift;
 557        if ($string eq EMPTY_CONTENT) {
 558                $string = "";
 559        }
 560        # This \n is important. This is due to mediawiki's way to handle end of files.
 561        return $string."\n";
 562}
 563
 564sub mediawiki_clean_filename {
 565        my $filename = shift;
 566        $filename =~ s{@{[SLASH_REPLACEMENT]}}{/}g;
 567        # [, ], |, {, and } are forbidden by MediaWiki, even URL-encoded.
 568        # Do a variant of URL-encoding, i.e. looks like URL-encoding,
 569        # but with _ added to prevent MediaWiki from thinking this is
 570        # an actual special character.
 571        $filename =~ s/[\[\]\{\}\|]/sprintf("_%%_%x", ord($&))/ge;
 572        # If we use the uri escape before
 573        # we should unescape here, before anything
 574
 575        return $filename;
 576}
 577
 578sub mediawiki_smudge_filename {
 579        my $filename = shift;
 580        $filename =~ s{/}{@{[SLASH_REPLACEMENT]}}g;
 581        $filename =~ s/ /_/g;
 582        # Decode forbidden characters encoded in mediawiki_clean_filename
 583        $filename =~ s/_%_([0-9a-fA-F][0-9a-fA-F])/sprintf("%c", hex($1))/ge;
 584        return $filename;
 585}
 586
 587sub literal_data {
 588        my ($content) = @_;
 589        print STDOUT "data ", bytes::length($content), "\n", $content;
 590        return;
 591}
 592
 593sub literal_data_raw {
 594        # Output possibly binary content.
 595        my ($content) = @_;
 596        # Avoid confusion between size in bytes and in characters
 597        utf8::downgrade($content);
 598        binmode STDOUT, ":raw";
 599        print STDOUT "data ", bytes::length($content), "\n", $content;
 600        binmode STDOUT, ":encoding(UTF-8)";
 601        return;
 602}
 603
 604sub mw_capabilities {
 605        # Revisions are imported to the private namespace
 606        # refs/mediawiki/$remotename/ by the helper and fetched into
 607        # refs/remotes/$remotename later by fetch.
 608        print STDOUT "refspec refs/heads/*:refs/mediawiki/$remotename/*\n";
 609        print STDOUT "import\n";
 610        print STDOUT "list\n";
 611        print STDOUT "push\n";
 612        print STDOUT "\n";
 613        return;
 614}
 615
 616sub mw_list {
 617        # MediaWiki do not have branches, we consider one branch arbitrarily
 618        # called master, and HEAD pointing to it.
 619        print STDOUT "? refs/heads/master\n";
 620        print STDOUT "\@refs/heads/master HEAD\n";
 621        print STDOUT "\n";
 622        return;
 623}
 624
 625sub mw_option {
 626        print STDERR "remote-helper command 'option $_[0]' not yet implemented\n";
 627        print STDOUT "unsupported\n";
 628        return;
 629}
 630
 631sub fetch_mw_revisions_for_page {
 632        my $page = shift;
 633        my $id = shift;
 634        my $fetch_from = shift;
 635        my @page_revs = ();
 636        my $query = {
 637                action => 'query',
 638                prop => 'revisions',
 639                rvprop => 'ids',
 640                rvdir => 'newer',
 641                rvstartid => $fetch_from,
 642                rvlimit => 500,
 643                pageids => $id,
 644        };
 645
 646        my $revnum = 0;
 647        # Get 500 revisions at a time due to the mediawiki api limit
 648        while (1) {
 649                my $result = $mediawiki->api($query);
 650
 651                # Parse each of those 500 revisions
 652                foreach my $revision (@{$result->{query}->{pages}->{$id}->{revisions}}) {
 653                        my $page_rev_ids;
 654                        $page_rev_ids->{pageid} = $page->{pageid};
 655                        $page_rev_ids->{revid} = $revision->{revid};
 656                        push(@page_revs, $page_rev_ids);
 657                        $revnum++;
 658                }
 659                last unless $result->{'query-continue'};
 660                $query->{rvstartid} = $result->{'query-continue'}->{revisions}->{rvstartid};
 661        }
 662        if ($shallow_import && @page_revs) {
 663                print STDERR "  Found 1 revision (shallow import).\n";
 664                @page_revs = sort {$b->{revid} <=> $a->{revid}} (@page_revs);
 665                return $page_revs[0];
 666        }
 667        print STDERR "  Found ", $revnum, " revision(s).\n";
 668        return @page_revs;
 669}
 670
 671sub fetch_mw_revisions {
 672        my $pages = shift; my @pages = @{$pages};
 673        my $fetch_from = shift;
 674
 675        my @revisions = ();
 676        my $n = 1;
 677        foreach my $page (@pages) {
 678                my $id = $page->{pageid};
 679
 680                print STDERR "page $n/", scalar(@pages), ": ". $page->{title} ."\n";
 681                $n++;
 682                my @page_revs = fetch_mw_revisions_for_page($page, $id, $fetch_from);
 683                @revisions = (@page_revs, @revisions);
 684        }
 685
 686        return ($n, @revisions);
 687}
 688
 689sub fe_escape_path {
 690    my $path = shift;
 691    $path =~ s/\\/\\\\/g;
 692    $path =~ s/"/\\"/g;
 693    $path =~ s/\n/\\n/g;
 694    return '"' . $path . '"';
 695}
 696
 697sub import_file_revision {
 698        my $commit = shift;
 699        my %commit = %{$commit};
 700        my $full_import = shift;
 701        my $n = shift;
 702        my $mediafile = shift;
 703        my %mediafile;
 704        if ($mediafile) {
 705                %mediafile = %{$mediafile};
 706        }
 707
 708        my $title = $commit{title};
 709        my $comment = $commit{comment};
 710        my $content = $commit{content};
 711        my $author = $commit{author};
 712        my $date = $commit{date};
 713
 714        print STDOUT "commit refs/mediawiki/$remotename/master\n";
 715        print STDOUT "mark :$n\n";
 716        print STDOUT "committer $author <$author\@$wiki_name> ", $date->epoch, " +0000\n";
 717        literal_data($comment);
 718
 719        # If it's not a clone, we need to know where to start from
 720        if (!$full_import && $n == 1) {
 721                print STDOUT "from refs/mediawiki/$remotename/master^0\n";
 722        }
 723        if ($content ne DELETED_CONTENT) {
 724                print STDOUT "M 644 inline " .
 725                    fe_escape_path($title . ".mw") . "\n";
 726                literal_data($content);
 727                if (%mediafile) {
 728                        print STDOUT "M 644 inline "
 729                            . fe_escape_path($mediafile{title}) . "\n";
 730                        literal_data_raw($mediafile{content});
 731                }
 732                print STDOUT "\n\n";
 733        } else {
 734                print STDOUT "D " . fe_escape_path($title . ".mw") . "\n";
 735        }
 736
 737        # mediawiki revision number in the git note
 738        if ($full_import && $n == 1) {
 739                print STDOUT "reset refs/notes/$remotename/mediawiki\n";
 740        }
 741        print STDOUT "commit refs/notes/$remotename/mediawiki\n";
 742        print STDOUT "committer $author <$author\@$wiki_name> ", $date->epoch, " +0000\n";
 743        literal_data("Note added by git-mediawiki during import");
 744        if (!$full_import && $n == 1) {
 745                print STDOUT "from refs/notes/$remotename/mediawiki^0\n";
 746        }
 747        print STDOUT "N inline :$n\n";
 748        literal_data("mediawiki_revision: " . $commit{mw_revision});
 749        print STDOUT "\n\n";
 750        return;
 751}
 752
 753# parse a sequence of
 754# <cmd> <arg1>
 755# <cmd> <arg2>
 756# \n
 757# (like batch sequence of import and sequence of push statements)
 758sub get_more_refs {
 759        my $cmd = shift;
 760        my @refs;
 761        while (1) {
 762                my $line = <STDIN>;
 763                if ($line =~ /^$cmd (.*)$/) {
 764                        push(@refs, $1);
 765                } elsif ($line eq "\n") {
 766                        return @refs;
 767                } else {
 768                        die("Invalid command in a '$cmd' batch: $_\n");
 769                }
 770        }
 771        return;
 772}
 773
 774sub mw_import {
 775        # multiple import commands can follow each other.
 776        my @refs = (shift, get_more_refs("import"));
 777        foreach my $ref (@refs) {
 778                mw_import_ref($ref);
 779        }
 780        print STDOUT "done\n";
 781        return;
 782}
 783
 784sub mw_import_ref {
 785        my $ref = shift;
 786        # The remote helper will call "import HEAD" and
 787        # "import refs/heads/master".
 788        # Since HEAD is a symbolic ref to master (by convention,
 789        # followed by the output of the command "list" that we gave),
 790        # we don't need to do anything in this case.
 791        if ($ref eq "HEAD") {
 792                return;
 793        }
 794
 795        mw_connect_maybe();
 796
 797        print STDERR "Searching revisions...\n";
 798        my $last_local = get_last_local_revision();
 799        my $fetch_from = $last_local + 1;
 800        if ($fetch_from == 1) {
 801                print STDERR ", fetching from beginning.\n";
 802        } else {
 803                print STDERR ", fetching from here.\n";
 804        }
 805
 806        my $n = 0;
 807        if ($fetch_strategy eq "by_rev") {
 808                print STDERR "Fetching & writing export data by revs...\n";
 809                $n = mw_import_ref_by_revs($fetch_from);
 810        } elsif ($fetch_strategy eq "by_page") {
 811                print STDERR "Fetching & writing export data by pages...\n";
 812                $n = mw_import_ref_by_pages($fetch_from);
 813        } else {
 814                print STDERR "fatal: invalid fetch strategy \"$fetch_strategy\".\n";
 815                print STDERR "Check your configuration variables remote.$remotename.fetchStrategy and mediawiki.fetchStrategy\n";
 816                exit 1;
 817        }
 818
 819        if ($fetch_from == 1 && $n == 0) {
 820                print STDERR "You appear to have cloned an empty MediaWiki.\n";
 821                # Something has to be done remote-helper side. If nothing is done, an error is
 822                # thrown saying that HEAD is referring to unknown object 0000000000000000000
 823                # and the clone fails.
 824        }
 825        return;
 826}
 827
 828sub mw_import_ref_by_pages {
 829
 830        my $fetch_from = shift;
 831        my %pages_hash = get_mw_pages();
 832        my @pages = values(%pages_hash);
 833
 834        my ($n, @revisions) = fetch_mw_revisions(\@pages, $fetch_from);
 835
 836        @revisions = sort {$a->{revid} <=> $b->{revid}} @revisions;
 837        my @revision_ids = map { $_->{revid} } @revisions;
 838
 839        return mw_import_revids($fetch_from, \@revision_ids, \%pages_hash);
 840}
 841
 842sub mw_import_ref_by_revs {
 843
 844        my $fetch_from = shift;
 845        my %pages_hash = get_mw_pages();
 846
 847        my $last_remote = get_last_global_remote_rev();
 848        my @revision_ids = $fetch_from..$last_remote;
 849        return mw_import_revids($fetch_from, \@revision_ids, \%pages_hash);
 850}
 851
 852# Import revisions given in second argument (array of integers).
 853# Only pages appearing in the third argument (hash indexed by page titles)
 854# will be imported.
 855sub mw_import_revids {
 856        my $fetch_from = shift;
 857        my $revision_ids = shift;
 858        my $pages = shift;
 859
 860        my $n = 0;
 861        my $n_actual = 0;
 862        my $last_timestamp = 0; # Placeholer in case $rev->timestamp is undefined
 863
 864        foreach my $pagerevid (@$revision_ids) {
 865                # Count page even if we skip it, since we display
 866                # $n/$total and $total includes skipped pages.
 867                $n++;
 868
 869                # fetch the content of the pages
 870                my $query = {
 871                        action => 'query',
 872                        prop => 'revisions',
 873                        rvprop => 'content|timestamp|comment|user|ids',
 874                        revids => $pagerevid,
 875                };
 876
 877                my $result = $mediawiki->api($query);
 878
 879                if (!$result) {
 880                        die "Failed to retrieve modified page for revision $pagerevid\n";
 881                }
 882
 883                if (defined($result->{query}->{badrevids}->{$pagerevid})) {
 884                        # The revision id does not exist on the remote wiki.
 885                        next;
 886                }
 887
 888                if (!defined($result->{query}->{pages})) {
 889                        die "Invalid revision $pagerevid.\n";
 890                }
 891
 892                my @result_pages = values(%{$result->{query}->{pages}});
 893                my $result_page = $result_pages[0];
 894                my $rev = $result_pages[0]->{revisions}->[0];
 895
 896                my $page_title = $result_page->{title};
 897
 898                if (!exists($pages->{$page_title})) {
 899                        print STDERR "$n/", scalar(@$revision_ids),
 900                                ": Skipping revision #$rev->{revid} of $page_title\n";
 901                        next;
 902                }
 903
 904                $n_actual++;
 905
 906                my %commit;
 907                $commit{author} = $rev->{user} || 'Anonymous';
 908                $commit{comment} = $rev->{comment} || EMPTY_MESSAGE;
 909                $commit{title} = mediawiki_smudge_filename($page_title);
 910                $commit{mw_revision} = $rev->{revid};
 911                $commit{content} = mediawiki_smudge($rev->{'*'});
 912
 913                if (!defined($rev->{timestamp})) {
 914                        $last_timestamp++;
 915                } else {
 916                        $last_timestamp = $rev->{timestamp};
 917                }
 918                $commit{date} = DateTime::Format::ISO8601->parse_datetime($last_timestamp);
 919
 920                # Differentiates classic pages and media files.
 921                my ($namespace, $filename) = $page_title =~ /^([^:]*):(.*)$/;
 922                my %mediafile;
 923                if ($namespace) {
 924                        my $id = get_mw_namespace_id($namespace);
 925                        if ($id && $id == get_mw_namespace_id("File")) {
 926                                %mediafile = get_mw_mediafile_for_page_revision($filename, $rev->{timestamp});
 927                        }
 928                }
 929                # If this is a revision of the media page for new version
 930                # of a file do one common commit for both file and media page.
 931                # Else do commit only for that page.
 932                print STDERR "$n/", scalar(@$revision_ids), ": Revision #$rev->{revid} of $commit{title}\n";
 933                import_file_revision(\%commit, ($fetch_from == 1), $n_actual, \%mediafile);
 934        }
 935
 936        return $n_actual;
 937}
 938
 939sub error_non_fast_forward {
 940        my $advice = run_git("config --bool advice.pushNonFastForward");
 941        chomp($advice);
 942        if ($advice ne "false") {
 943                # Native git-push would show this after the summary.
 944                # We can't ask it to display it cleanly, so print it
 945                # ourselves before.
 946                print STDERR "To prevent you from losing history, non-fast-forward updates were rejected\n";
 947                print STDERR "Merge the remote changes (e.g. 'git pull') before pushing again. See the\n";
 948                print STDERR "'Note about fast-forwards' section of 'git push --help' for details.\n";
 949        }
 950        print STDOUT "error $_[0] \"non-fast-forward\"\n";
 951        return 0;
 952}
 953
 954sub mw_upload_file {
 955        my $complete_file_name = shift;
 956        my $new_sha1 = shift;
 957        my $extension = shift;
 958        my $file_deleted = shift;
 959        my $summary = shift;
 960        my $newrevid;
 961        my $path = "File:" . $complete_file_name;
 962        my %hashFiles = get_allowed_file_extensions();
 963        if (!exists($hashFiles{$extension})) {
 964                print STDERR "$complete_file_name is not a permitted file on this wiki.\n";
 965                print STDERR "Check the configuration of file uploads in your mediawiki.\n";
 966                return $newrevid;
 967        }
 968        # Deleting and uploading a file requires a priviledged user
 969        if ($file_deleted) {
 970                mw_connect_maybe();
 971                my $query = {
 972                        action => 'delete',
 973                        title => $path,
 974                        reason => $summary
 975                };
 976                if (!$mediawiki->edit($query)) {
 977                        print STDERR "Failed to delete file on remote wiki\n";
 978                        print STDERR "Check your permissions on the remote site. Error code:\n";
 979                        print STDERR $mediawiki->{error}->{code} . ':' . $mediawiki->{error}->{details};
 980                        exit 1;
 981                }
 982        } else {
 983                # Don't let perl try to interpret file content as UTF-8 => use "raw"
 984                my $content = run_git("cat-file blob $new_sha1", "raw");
 985                if ($content ne "") {
 986                        mw_connect_maybe();
 987                        $mediawiki->{config}->{upload_url} =
 988                                "$url/index.php/Special:Upload";
 989                        $mediawiki->edit({
 990                                action => 'upload',
 991                                filename => $complete_file_name,
 992                                comment => $summary,
 993                                file => [undef,
 994                                         $complete_file_name,
 995                                         Content => $content],
 996                                ignorewarnings => 1,
 997                        }, {
 998                                skip_encoding => 1
 999                        } ) || die $mediawiki->{error}->{code} . ':'
1000                                 . $mediawiki->{error}->{details} . "\n";
1001                        my $last_file_page = $mediawiki->get_page({title => $path});
1002                        $newrevid = $last_file_page->{revid};
1003                        print STDERR "Pushed file: $new_sha1 - $complete_file_name.\n";
1004                } else {
1005                        print STDERR "Empty file $complete_file_name not pushed.\n";
1006                }
1007        }
1008        return $newrevid;
1009}
1010
1011sub mw_push_file {
1012        my $diff_info = shift;
1013        # $diff_info contains a string in this format:
1014        # 100644 100644 <sha1_of_blob_before_commit> <sha1_of_blob_now> <status>
1015        my @diff_info_split = split(/[ \t]/, $diff_info);
1016
1017        # Filename, including .mw extension
1018        my $complete_file_name = shift;
1019        # Commit message
1020        my $summary = shift;
1021        # MediaWiki revision number. Keep the previous one by default,
1022        # in case there's no edit to perform.
1023        my $oldrevid = shift;
1024        my $newrevid;
1025
1026        if ($summary eq EMPTY_MESSAGE) {
1027                $summary = '';
1028        }
1029
1030        my $new_sha1 = $diff_info_split[3];
1031        my $old_sha1 = $diff_info_split[2];
1032        my $page_created = ($old_sha1 eq NULL_SHA1);
1033        my $page_deleted = ($new_sha1 eq NULL_SHA1);
1034        $complete_file_name = mediawiki_clean_filename($complete_file_name);
1035
1036        my ($title, $extension) = $complete_file_name =~ /^(.*)\.([^\.]*)$/;
1037        if (!defined($extension)) {
1038                $extension = "";
1039        }
1040        if ($extension eq "mw") {
1041                my $ns = get_mw_namespace_id_for_page($complete_file_name);
1042                if ($ns && $ns == get_mw_namespace_id("File") && (!$export_media)) {
1043                        print STDERR "Ignoring media file related page: $complete_file_name\n";
1044                        return ($oldrevid, "ok");
1045                }
1046                my $file_content;
1047                if ($page_deleted) {
1048                        # Deleting a page usually requires
1049                        # special privileges. A common
1050                        # convention is to replace the page
1051                        # with this content instead:
1052                        $file_content = DELETED_CONTENT;
1053                } else {
1054                        $file_content = run_git("cat-file blob $new_sha1");
1055                }
1056
1057                mw_connect_maybe();
1058
1059                my $result = $mediawiki->edit( {
1060                        action => 'edit',
1061                        summary => $summary,
1062                        title => $title,
1063                        basetimestamp => $basetimestamps{$oldrevid},
1064                        text => mediawiki_clean($file_content, $page_created),
1065                                  }, {
1066                                          skip_encoding => 1 # Helps with names with accentuated characters
1067                                  });
1068                if (!$result) {
1069                        if ($mediawiki->{error}->{code} == 3) {
1070                                # edit conflicts, considered as non-fast-forward
1071                                print STDERR 'Warning: Error ' .
1072                                    $mediawiki->{error}->{code} .
1073                                    ' from mediwiki: ' . $mediawiki->{error}->{details} .
1074                                    ".\n";
1075                                return ($oldrevid, "non-fast-forward");
1076                        } else {
1077                                # Other errors. Shouldn't happen => just die()
1078                                die 'Fatal: Error ' .
1079                                    $mediawiki->{error}->{code} .
1080                                    ' from mediwiki: ' . $mediawiki->{error}->{details} . "\n";
1081                        }
1082                }
1083                $newrevid = $result->{edit}->{newrevid};
1084                print STDERR "Pushed file: $new_sha1 - $title\n";
1085        } elsif ($export_media) {
1086                $newrevid = mw_upload_file($complete_file_name, $new_sha1,
1087                                           $extension, $page_deleted,
1088                                           $summary);
1089        } else {
1090                print STDERR "Ignoring media file $title\n";
1091        }
1092        $newrevid = ($newrevid or $oldrevid);
1093        return ($newrevid, "ok");
1094}
1095
1096sub mw_push {
1097        # multiple push statements can follow each other
1098        my @refsspecs = (shift, get_more_refs("push"));
1099        my $pushed;
1100        for my $refspec (@refsspecs) {
1101                my ($force, $local, $remote) = $refspec =~ /^(\+)?([^:]*):([^:]*)$/
1102                    or die("Invalid refspec for push. Expected <src>:<dst> or +<src>:<dst>\n");
1103                if ($force) {
1104                        print STDERR "Warning: forced push not allowed on a MediaWiki.\n";
1105                }
1106                if ($local eq "") {
1107                        print STDERR "Cannot delete remote branch on a MediaWiki\n";
1108                        print STDOUT "error $remote cannot delete\n";
1109                        next;
1110                }
1111                if ($remote ne "refs/heads/master") {
1112                        print STDERR "Only push to the branch 'master' is supported on a MediaWiki\n";
1113                        print STDOUT "error $remote only master allowed\n";
1114                        next;
1115                }
1116                if (mw_push_revision($local, $remote)) {
1117                        $pushed = 1;
1118                }
1119        }
1120
1121        # Notify Git that the push is done
1122        print STDOUT "\n";
1123
1124        if ($pushed && $dumb_push) {
1125                print STDERR "Just pushed some revisions to MediaWiki.\n";
1126                print STDERR "The pushed revisions now have to be re-imported, and your current branch\n";
1127                print STDERR "needs to be updated with these re-imported commits. You can do this with\n";
1128                print STDERR "\n";
1129                print STDERR "  git pull --rebase\n";
1130                print STDERR "\n";
1131        }
1132        return;
1133}
1134
1135sub mw_push_revision {
1136        my $local = shift;
1137        my $remote = shift; # actually, this has to be "refs/heads/master" at this point.
1138        my $last_local_revid = get_last_local_revision();
1139        print STDERR ".\n"; # Finish sentence started by get_last_local_revision()
1140        my $last_remote_revid = get_last_remote_revision();
1141        my $mw_revision = $last_remote_revid;
1142
1143        # Get sha1 of commit pointed by local HEAD
1144        my $HEAD_sha1 = run_git("rev-parse $local 2>/dev/null"); chomp($HEAD_sha1);
1145        # Get sha1 of commit pointed by remotes/$remotename/master
1146        my $remoteorigin_sha1 = run_git("rev-parse refs/remotes/$remotename/master 2>/dev/null");
1147        chomp($remoteorigin_sha1);
1148
1149        if ($last_local_revid > 0 &&
1150            $last_local_revid < $last_remote_revid) {
1151                return error_non_fast_forward($remote);
1152        }
1153
1154        if ($HEAD_sha1 eq $remoteorigin_sha1) {
1155                # nothing to push
1156                return 0;
1157        }
1158
1159        # Get every commit in between HEAD and refs/remotes/origin/master,
1160        # including HEAD and refs/remotes/origin/master
1161        my @commit_pairs = ();
1162        if ($last_local_revid > 0) {
1163                my $parsed_sha1 = $remoteorigin_sha1;
1164                # Find a path from last MediaWiki commit to pushed commit
1165                print STDERR "Computing path from local to remote ...\n";
1166                my @local_ancestry = split(/\n/, run_git("rev-list --boundary --parents $local ^$parsed_sha1"));
1167                my %local_ancestry;
1168                foreach my $line (@local_ancestry) {
1169                        if (my ($child, $parents) = $line =~ /^-?([a-f0-9]+) ([a-f0-9 ]+)/) {
1170                                foreach my $parent (split(/ /, $parents)) {
1171                                        $local_ancestry{$parent} = $child;
1172                                }
1173                        } elsif (!$line =~ /^([a-f0-9]+)/) {
1174                                die "Unexpected output from git rev-list: $line\n";
1175                        }
1176                }
1177                while ($parsed_sha1 ne $HEAD_sha1) {
1178                        my $child = $local_ancestry{$parsed_sha1};
1179                        if (!$child) {
1180                                printf STDERR "Cannot find a path in history from remote commit to last commit\n";
1181                                return error_non_fast_forward($remote);
1182                        }
1183                        push(@commit_pairs, [$parsed_sha1, $child]);
1184                        $parsed_sha1 = $child;
1185                }
1186        } else {
1187                # No remote mediawiki revision. Export the whole
1188                # history (linearized with --first-parent)
1189                print STDERR "Warning: no common ancestor, pushing complete history\n";
1190                my $history = run_git("rev-list --first-parent --children $local");
1191                my @history = split(/\n/, $history);
1192                @history = @history[1..$#history];
1193                foreach my $line (reverse @history) {
1194                        my @commit_info_split = split(/[ \n]/, $line);
1195                        push(@commit_pairs, \@commit_info_split);
1196                }
1197        }
1198
1199        foreach my $commit_info_split (@commit_pairs) {
1200                my $sha1_child = @{$commit_info_split}[0];
1201                my $sha1_commit = @{$commit_info_split}[1];
1202                my $diff_infos = run_git("diff-tree -r --raw -z $sha1_child $sha1_commit");
1203                # TODO: we could detect rename, and encode them with a #redirect on the wiki.
1204                # TODO: for now, it's just a delete+add
1205                my @diff_info_list = split(/\0/, $diff_infos);
1206                # Keep the subject line of the commit message as mediawiki comment for the revision
1207                my $commit_msg = run_git("log --no-walk --format=\"%s\" $sha1_commit");
1208                chomp($commit_msg);
1209                # Push every blob
1210                while (@diff_info_list) {
1211                        my $status;
1212                        # git diff-tree -z gives an output like
1213                        # <metadata>\0<filename1>\0
1214                        # <metadata>\0<filename2>\0
1215                        # and we've split on \0.
1216                        my $info = shift(@diff_info_list);
1217                        my $file = shift(@diff_info_list);
1218                        ($mw_revision, $status) = mw_push_file($info, $file, $commit_msg, $mw_revision);
1219                        if ($status eq "non-fast-forward") {
1220                                # we may already have sent part of the
1221                                # commit to MediaWiki, but it's too
1222                                # late to cancel it. Stop the push in
1223                                # the middle, but still give an
1224                                # accurate error message.
1225                                return error_non_fast_forward($remote);
1226                        }
1227                        if ($status ne "ok") {
1228                                die("Unknown error from mw_push_file()\n");
1229                        }
1230                }
1231                unless ($dumb_push) {
1232                        run_git("notes --ref=$remotename/mediawiki add -f -m \"mediawiki_revision: $mw_revision\" $sha1_commit");
1233                        run_git("update-ref -m \"Git-MediaWiki push\" refs/mediawiki/$remotename/master $sha1_commit $sha1_child");
1234                }
1235        }
1236
1237        print STDOUT "ok $remote\n";
1238        return 1;
1239}
1240
1241sub get_allowed_file_extensions {
1242        mw_connect_maybe();
1243
1244        my $query = {
1245                action => 'query',
1246                meta => 'siteinfo',
1247                siprop => 'fileextensions'
1248                };
1249        my $result = $mediawiki->api($query);
1250        my @file_extensions = map { $_->{ext}} @{$result->{query}->{fileextensions}};
1251        my %hashFile = map { $_ => 1 } @file_extensions;
1252
1253        return %hashFile;
1254}
1255
1256# In memory cache for MediaWiki namespace ids.
1257my %namespace_id;
1258
1259# Namespaces whose id is cached in the configuration file
1260# (to avoid duplicates)
1261my %cached_mw_namespace_id;
1262
1263# Return MediaWiki id for a canonical namespace name.
1264# Ex.: "File", "Project".
1265sub get_mw_namespace_id {
1266        mw_connect_maybe();
1267        my $name = shift;
1268
1269        if (!exists $namespace_id{$name}) {
1270                # Look at configuration file, if the record for that namespace is
1271                # already cached. Namespaces are stored in form:
1272                # "Name_of_namespace:Id_namespace", ex.: "File:6".
1273                my @temp = split(/\n/, run_git("config --get-all remote."
1274                                                . $remotename .".namespaceCache"));
1275                chomp(@temp);
1276                foreach my $ns (@temp) {
1277                        my ($n, $id) = split(/:/, $ns);
1278                        if ($id eq 'notANameSpace') {
1279                                $namespace_id{$n} = {is_namespace => 0};
1280                        } else {
1281                                $namespace_id{$n} = {is_namespace => 1, id => $id};
1282                        }
1283                        $cached_mw_namespace_id{$n} = 1;
1284                }
1285        }
1286
1287        if (!exists $namespace_id{$name}) {
1288                print STDERR "Namespace $name not found in cache, querying the wiki ...\n";
1289                # NS not found => get namespace id from MW and store it in
1290                # configuration file.
1291                my $query = {
1292                        action => 'query',
1293                        meta => 'siteinfo',
1294                        siprop => 'namespaces'
1295                };
1296                my $result = $mediawiki->api($query);
1297
1298                while (my ($id, $ns) = each(%{$result->{query}->{namespaces}})) {
1299                        if (defined($ns->{id}) && defined($ns->{canonical})) {
1300                                $namespace_id{$ns->{canonical}} = {is_namespace => 1, id => $ns->{id}};
1301                                if ($ns->{'*'}) {
1302                                        # alias (e.g. french Fichier: as alias for canonical File:)
1303                                        $namespace_id{$ns->{'*'}} = {is_namespace => 1, id => $ns->{id}};
1304                                }
1305                        }
1306                }
1307        }
1308
1309        my $ns = $namespace_id{$name};
1310        my $id;
1311
1312        unless (defined $ns) {
1313                print STDERR "No such namespace $name on MediaWiki.\n";
1314                $ns = {is_namespace => 0};
1315                $namespace_id{$name} = $ns;
1316        }
1317
1318        if ($ns->{is_namespace}) {
1319                $id = $ns->{id};
1320        }
1321
1322        # Store "notANameSpace" as special value for inexisting namespaces
1323        my $store_id = ($id || 'notANameSpace');
1324
1325        # Store explicitely requested namespaces on disk
1326        if (!exists $cached_mw_namespace_id{$name}) {
1327                run_git("config --add remote.". $remotename
1328                        .".namespaceCache \"". $name .":". $store_id ."\"");
1329                $cached_mw_namespace_id{$name} = 1;
1330        }
1331        return $id;
1332}
1333
1334sub get_mw_namespace_id_for_page {
1335        my $namespace = shift;
1336        if ($namespace =~ /^([^:]*):/) {
1337                return get_mw_namespace_id($namespace);
1338        } else {
1339                return;
1340        }
1341}