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