Andrew's git - gitweb.git/blob

aa526b7006f278e8df7a58e5eb45c3d2f863fca0
   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 = map $_->{title}, @{$page->{links}};
 403                                push(@media_titles, @link_titles);
 404                        }
 405                        if (defined($page->{images})) {
 406                                my @image_titles = map $_->{title}, @{$page->{images}};
 407                                push(@media_titles, @image_titles);
 408                        }
 409                        if (@media_titles) {
 410                                get_mw_page_list(\@media_titles, $pages);
 411                        }
 412                }
 413
 414                @titles = @titles[($batch+1)..$#titles];
 415        }
 416        return;
 417}
 418
 419sub get_mw_mediafile_for_page_revision {
 420        # Name of the file on Wiki, with the prefix.
 421        my $filename = shift;
 422        my $timestamp = shift;
 423        my %mediafile;
 424
 425        # Search if on a media file with given timestamp exists on
 426        # MediaWiki. In that case download the file.
 427        my $query = {
 428                action => 'query',
 429                prop => 'imageinfo',
 430                titles => "File:" . $filename,
 431                iistart => $timestamp,
 432                iiend => $timestamp,
 433                iiprop => 'timestamp|archivename|url',
 434                iilimit => 1
 435        };
 436        my $result = $mediawiki->api($query);
 437
 438        my ($fileid, $file) = each( %{$result->{query}->{pages}} );
 439        # If not defined it means there is no revision of the file for
 440        # given timestamp.
 441        if (defined($file->{imageinfo})) {
 442                $mediafile{title} = $filename;
 443
 444                my $fileinfo = pop(@{$file->{imageinfo}});
 445                $mediafile{timestamp} = $fileinfo->{timestamp};
 446                # Mediawiki::API's download function doesn't support https URLs
 447                # and can't download old versions of files.
 448                print STDERR "\tDownloading file $mediafile{title}, version $mediafile{timestamp}\n";
 449                $mediafile{content} = download_mw_mediafile($fileinfo->{url});
 450        }
 451        return %mediafile;
 452}
 453
 454sub download_mw_mediafile {
 455        my $url = shift;
 456
 457        my $response = $mediawiki->{ua}->get($url);
 458        if ($response->code == 200) {
 459                return $response->decoded_content;
 460        } else {
 461                print STDERR "Error downloading mediafile from :\n";
 462                print STDERR "URL: $url\n";
 463                print STDERR "Server response: " . $response->code . " " . $response->message . "\n";
 464                exit 1;
 465        }
 466}
 467
 468sub get_last_local_revision {
 469        # Get note regarding last mediawiki revision
 470        my $note = run_git("notes --ref=$remotename/mediawiki show refs/mediawiki/$remotename/master 2>/dev/null");
 471        my @note_info = split(/ /, $note);
 472
 473        my $lastrevision_number;
 474        if (!(defined($note_info[0]) && $note_info[0] eq "mediawiki_revision:")) {
 475                print STDERR "No previous mediawiki revision found";
 476                $lastrevision_number = 0;
 477        } else {
 478                # Notes are formatted : mediawiki_revision: #number
 479                $lastrevision_number = $note_info[1];
 480                chomp($lastrevision_number);
 481                print STDERR "Last local mediawiki revision found is $lastrevision_number";
 482        }
 483        return $lastrevision_number;
 484}
 485
 486# Get the last remote revision without taking in account which pages are
 487# tracked or not. This function makes a single request to the wiki thus
 488# avoid a loop onto all tracked pages. This is useful for the fetch-by-rev
 489# option.
 490sub get_last_global_remote_rev {
 491        mw_connect_maybe();
 492
 493        my $query = {
 494                action => 'query',
 495                list => 'recentchanges',
 496                prop => 'revisions',
 497                rclimit => '1',
 498                rcdir => 'older',
 499        };
 500        my $result = $mediawiki->api($query);
 501        return $result->{query}->{recentchanges}[0]->{revid};
 502}
 503
 504# Get the last remote revision concerning the tracked pages and the tracked
 505# categories.
 506sub get_last_remote_revision {
 507        mw_connect_maybe();
 508
 509        my %pages_hash = get_mw_pages();
 510        my @pages = values(%pages_hash);
 511
 512        my $max_rev_num = 0;
 513
 514        print STDERR "Getting last revision id on tracked pages...\n";
 515
 516        foreach my $page (@pages) {
 517                my $id = $page->{pageid};
 518
 519                my $query = {
 520                        action => 'query',
 521                        prop => 'revisions',
 522                        rvprop => 'ids|timestamp',
 523                        pageids => $id,
 524                };
 525
 526                my $result = $mediawiki->api($query);
 527
 528                my $lastrev = pop(@{$result->{query}->{pages}->{$id}->{revisions}});
 529
 530                $basetimestamps{$lastrev->{revid}} = $lastrev->{timestamp};
 531
 532                $max_rev_num = ($lastrev->{revid} > $max_rev_num ? $lastrev->{revid} : $max_rev_num);
 533        }
 534
 535        print STDERR "Last remote revision found is $max_rev_num.\n";
 536        return $max_rev_num;
 537}
 538
 539# Clean content before sending it to MediaWiki
 540sub mediawiki_clean {
 541        my $string = shift;
 542        my $page_created = shift;
 543        # Mediawiki does not allow blank space at the end of a page and ends with a single \n.
 544        # This function right trims a string and adds a \n at the end to follow this rule
 545        $string =~ s/\s+$//;
 546        if ($string eq "" && $page_created) {
 547                # Creating empty pages is forbidden.
 548                $string = EMPTY_CONTENT;
 549        }
 550        return $string."\n";
 551}
 552
 553# Filter applied on MediaWiki data before adding them to Git
 554sub mediawiki_smudge {
 555        my $string = shift;
 556        if ($string eq EMPTY_CONTENT) {
 557                $string = "";
 558        }
 559        # This \n is important. This is due to mediawiki's way to handle end of files.
 560        return $string."\n";
 561}
 562
 563sub mediawiki_clean_filename {
 564        my $filename = shift;
 565        $filename =~ s/@{[SLASH_REPLACEMENT]}/\//g;
 566        # [, ], |, {, and } are forbidden by MediaWiki, even URL-encoded.
 567        # Do a variant of URL-encoding, i.e. looks like URL-encoding,
 568        # but with _ added to prevent MediaWiki from thinking this is
 569        # an actual special character.
 570        $filename =~ s/[\[\]\{\}\|]/sprintf("_%%_%x", ord($&))/ge;
 571        # If we use the uri escape before
 572        # we should unescape here, before anything
 573
 574        return $filename;
 575}
 576
 577sub mediawiki_smudge_filename {
 578        my $filename = shift;
 579        $filename =~ s/\//@{[SLASH_REPLACEMENT]}/g;
 580        $filename =~ s/ /_/g;
 581        # Decode forbidden characters encoded in mediawiki_clean_filename
 582        $filename =~ s/_%_([0-9a-fA-F][0-9a-fA-F])/sprintf("%c", hex($1))/ge;
 583        return $filename;
 584}
 585
 586sub literal_data {
 587        my ($content) = @_;
 588        print STDOUT "data ", bytes::length($content), "\n", $content;
 589        return;
 590}
 591
 592sub literal_data_raw {
 593        # Output possibly binary content.
 594        my ($content) = @_;
 595        # Avoid confusion between size in bytes and in characters
 596        utf8::downgrade($content);
 597        binmode STDOUT, ":raw";
 598        print STDOUT "data ", bytes::length($content), "\n", $content;
 599        binmode STDOUT, ":encoding(UTF-8)";
 600        return;
 601}
 602
 603sub mw_capabilities {
 604        # Revisions are imported to the private namespace
 605        # refs/mediawiki/$remotename/ by the helper and fetched into
 606        # refs/remotes/$remotename later by fetch.
 607        print STDOUT "refspec refs/heads/*:refs/mediawiki/$remotename/*\n";
 608        print STDOUT "import\n";
 609        print STDOUT "list\n";
 610        print STDOUT "push\n";
 611        print STDOUT "\n";
 612        return;
 613}
 614
 615sub mw_list {
 616        # MediaWiki do not have branches, we consider one branch arbitrarily
 617        # called master, and HEAD pointing to it.
 618        print STDOUT "? refs/heads/master\n";
 619        print STDOUT "\@refs/heads/master HEAD\n";
 620        print STDOUT "\n";
 621        return;
 622}
 623
 624sub mw_option {
 625        print STDERR "remote-helper command 'option $_[0]' not yet implemented\n";
 626        print STDOUT "unsupported\n";
 627        return;
 628}
 629
 630sub fetch_mw_revisions_for_page {
 631        my $page = shift;
 632        my $id = shift;
 633        my $fetch_from = shift;
 634        my @page_revs = ();
 635        my $query = {
 636                action => 'query',
 637                prop => 'revisions',
 638                rvprop => 'ids',
 639                rvdir => 'newer',
 640                rvstartid => $fetch_from,
 641                rvlimit => 500,
 642                pageids => $id,
 643        };
 644
 645        my $revnum = 0;
 646        # Get 500 revisions at a time due to the mediawiki api limit
 647        while (1) {
 648                my $result = $mediawiki->api($query);
 649
 650                # Parse each of those 500 revisions
 651                foreach my $revision (@{$result->{query}->{pages}->{$id}->{revisions}}) {
 652                        my $page_rev_ids;
 653                        $page_rev_ids->{pageid} = $page->{pageid};
 654                        $page_rev_ids->{revid} = $revision->{revid};
 655                        push(@page_revs, $page_rev_ids);
 656                        $revnum++;
 657                }
 658                last unless $result->{'query-continue'};
 659                $query->{rvstartid} = $result->{'query-continue'}->{revisions}->{rvstartid};
 660        }
 661        if ($shallow_import && @page_revs) {
 662                print STDERR "  Found 1 revision (shallow import).\n";
 663                @page_revs = sort {$b->{revid} <=> $a->{revid}} (@page_revs);
 664                return $page_revs[0];
 665        }
 666        print STDERR "  Found ", $revnum, " revision(s).\n";
 667        return @page_revs;
 668}
 669
 670sub fetch_mw_revisions {
 671        my $pages = shift; my @pages = @{$pages};
 672        my $fetch_from = shift;
 673
 674        my @revisions = ();
 675        my $n = 1;
 676        foreach my $page (@pages) {
 677                my $id = $page->{pageid};
 678
 679                print STDERR "page $n/", scalar(@pages), ": ". $page->{title} ."\n";
 680                $n++;
 681                my @page_revs = fetch_mw_revisions_for_page($page, $id, $fetch_from);
 682                @revisions = (@page_revs, @revisions);
 683        }
 684
 685        return ($n, @revisions);
 686}
 687
 688sub fe_escape_path {
 689    my $path = shift;
 690    $path =~ s/\\/\\\\/g;
 691    $path =~ s/"/\\"/g;
 692    $path =~ s/\n/\\n/g;
 693    return '"' . $path . '"';
 694}
 695
 696sub import_file_revision {
 697        my $commit = shift;
 698        my %commit = %{$commit};
 699        my $full_import = shift;
 700        my $n = shift;
 701        my $mediafile = shift;
 702        my %mediafile;
 703        if ($mediafile) {
 704                %mediafile = %{$mediafile};
 705        }
 706
 707        my $title = $commit{title};
 708        my $comment = $commit{comment};
 709        my $content = $commit{content};
 710        my $author = $commit{author};
 711        my $date = $commit{date};
 712
 713        print STDOUT "commit refs/mediawiki/$remotename/master\n";
 714        print STDOUT "mark :$n\n";
 715        print STDOUT "committer $author <$author\@$wiki_name> ", $date->epoch, " +0000\n";
 716        literal_data($comment);
 717
 718        # If it's not a clone, we need to know where to start from
 719        if (!$full_import && $n == 1) {
 720                print STDOUT "from refs/mediawiki/$remotename/master^0\n";
 721        }
 722        if ($content ne DELETED_CONTENT) {
 723                print STDOUT "M 644 inline " .
 724                    fe_escape_path($title . ".mw") . "\n";
 725                literal_data($content);
 726                if (%mediafile) {
 727                        print STDOUT "M 644 inline "
 728                            . fe_escape_path($mediafile{title}) . "\n";
 729                        literal_data_raw($mediafile{content});
 730                }
 731                print STDOUT "\n\n";
 732        } else {
 733                print STDOUT "D " . fe_escape_path($title . ".mw") . "\n";
 734        }
 735
 736        # mediawiki revision number in the git note
 737        if ($full_import && $n == 1) {
 738                print STDOUT "reset refs/notes/$remotename/mediawiki\n";
 739        }
 740        print STDOUT "commit refs/notes/$remotename/mediawiki\n";
 741        print STDOUT "committer $author <$author\@$wiki_name> ", $date->epoch, " +0000\n";
 742        literal_data("Note added by git-mediawiki during import");
 743        if (!$full_import && $n == 1) {
 744                print STDOUT "from refs/notes/$remotename/mediawiki^0\n";
 745        }
 746        print STDOUT "N inline :$n\n";
 747        literal_data("mediawiki_revision: " . $commit{mw_revision});
 748        print STDOUT "\n\n";
 749        return;
 750}
 751
 752# parse a sequence of
 753# <cmd> <arg1>
 754# <cmd> <arg2>
 755# \n
 756# (like batch sequence of import and sequence of push statements)
 757sub get_more_refs {
 758        my $cmd = shift;
 759        my @refs;
 760        while (1) {
 761                my $line = <STDIN>;
 762                if ($line =~ m/^$cmd (.*)$/) {
 763                        push(@refs, $1);
 764                } elsif ($line eq "\n") {
 765                        return @refs;
 766                } else {
 767                        die("Invalid command in a '$cmd' batch: ". $_);
 768                }
 769        }
 770        return;
 771}
 772
 773sub mw_import {
 774        # multiple import commands can follow each other.
 775        my @refs = (shift, get_more_refs("import"));
 776        foreach my $ref (@refs) {
 777                mw_import_ref($ref);
 778        }
 779        print STDOUT "done\n";
 780        return;
 781}
 782
 783sub mw_import_ref {
 784        my $ref = shift;
 785        # The remote helper will call "import HEAD" and
 786        # "import refs/heads/master".
 787        # Since HEAD is a symbolic ref to master (by convention,
 788        # followed by the output of the command "list" that we gave),
 789        # we don't need to do anything in this case.
 790        if ($ref eq "HEAD") {
 791                return;
 792        }
 793
 794        mw_connect_maybe();
 795
 796        print STDERR "Searching revisions...\n";
 797        my $last_local = get_last_local_revision();
 798        my $fetch_from = $last_local + 1;
 799        if ($fetch_from == 1) {
 800                print STDERR ", fetching from beginning.\n";
 801        } else {
 802                print STDERR ", fetching from here.\n";
 803        }
 804
 805        my $n = 0;
 806        if ($fetch_strategy eq "by_rev") {
 807                print STDERR "Fetching & writing export data by revs...\n";
 808                $n = mw_import_ref_by_revs($fetch_from);
 809        } elsif ($fetch_strategy eq "by_page") {
 810                print STDERR "Fetching & writing export data by pages...\n";
 811                $n = mw_import_ref_by_pages($fetch_from);
 812        } else {
 813                print STDERR "fatal: invalid fetch strategy \"$fetch_strategy\".\n";
 814                print STDERR "Check your configuration variables remote.$remotename.fetchStrategy and mediawiki.fetchStrategy\n";
 815                exit 1;
 816        }
 817
 818        if ($fetch_from == 1 && $n == 0) {
 819                print STDERR "You appear to have cloned an empty MediaWiki.\n";
 820                # Something has to be done remote-helper side. If nothing is done, an error is
 821                # thrown saying that HEAD is referring to unknown object 0000000000000000000
 822                # and the clone fails.
 823        }
 824        return;
 825}
 826
 827sub mw_import_ref_by_pages {
 828
 829        my $fetch_from = shift;
 830        my %pages_hash = get_mw_pages();
 831        my @pages = values(%pages_hash);
 832
 833        my ($n, @revisions) = fetch_mw_revisions(\@pages, $fetch_from);
 834
 835        @revisions = sort {$a->{revid} <=> $b->{revid}} @revisions;
 836        my @revision_ids = map $_->{revid}, @revisions;
 837
 838        return mw_import_revids($fetch_from, \@revision_ids, \%pages_hash);
 839}
 840
 841sub mw_import_ref_by_revs {
 842
 843        my $fetch_from = shift;
 844        my %pages_hash = get_mw_pages();
 845
 846        my $last_remote = get_last_global_remote_rev();
 847        my @revision_ids = $fetch_from..$last_remote;
 848        return mw_import_revids($fetch_from, \@revision_ids, \%pages_hash);
 849}
 850
 851# Import revisions given in second argument (array of integers).
 852# Only pages appearing in the third argument (hash indexed by page titles)
 853# will be imported.
 854sub mw_import_revids {
 855        my $fetch_from = shift;
 856        my $revision_ids = shift;
 857        my $pages = shift;
 858
 859        my $n = 0;
 860        my $n_actual = 0;
 861        my $last_timestamp = 0; # Placeholer in case $rev->timestamp is undefined
 862
 863        foreach my $pagerevid (@$revision_ids) {
 864                # Count page even if we skip it, since we display
 865                # $n/$total and $total includes skipped pages.
 866                $n++;
 867
 868                # fetch the content of the pages
 869                my $query = {
 870                        action => 'query',
 871                        prop => 'revisions',
 872                        rvprop => 'content|timestamp|comment|user|ids',
 873                        revids => $pagerevid,
 874                };
 875
 876                my $result = $mediawiki->api($query);
 877
 878                if (!$result) {
 879                        die "Failed to retrieve modified page for revision $pagerevid";
 880                }
 881
 882                if (defined($result->{query}->{badrevids}->{$pagerevid})) {
 883                        # The revision id does not exist on the remote wiki.
 884                        next;
 885                }
 886
 887                if (!defined($result->{query}->{pages})) {
 888                        die "Invalid revision $pagerevid.";
 889                }
 890
 891                my @result_pages = values(%{$result->{query}->{pages}});
 892                my $result_page = $result_pages[0];
 893                my $rev = $result_pages[0]->{revisions}->[0];
 894
 895                my $page_title = $result_page->{title};
 896
 897                if (!exists($pages->{$page_title})) {
 898                        print STDERR "$n/", scalar(@$revision_ids),
 899                                ": Skipping revision #$rev->{revid} of $page_title\n";
 900                        next;
 901                }
 902
 903                $n_actual++;
 904
 905                my %commit;
 906                $commit{author} = $rev->{user} || 'Anonymous';
 907                $commit{comment} = $rev->{comment} || EMPTY_MESSAGE;
 908                $commit{title} = mediawiki_smudge_filename($page_title);
 909                $commit{mw_revision} = $rev->{revid};
 910                $commit{content} = mediawiki_smudge($rev->{'*'});
 911
 912                if (!defined($rev->{timestamp})) {
 913                        $last_timestamp++;
 914                } else {
 915                        $last_timestamp = $rev->{timestamp};
 916                }
 917                $commit{date} = DateTime::Format::ISO8601->parse_datetime($last_timestamp);
 918
 919                # Differentiates classic pages and media files.
 920                my ($namespace, $filename) = $page_title =~ /^([^:]*):(.*)$/;
 921                my %mediafile;
 922                if ($namespace) {
 923                        my $id = get_mw_namespace_id($namespace);
 924                        if ($id && $id == get_mw_namespace_id("File")) {
 925                                %mediafile = get_mw_mediafile_for_page_revision($filename, $rev->{timestamp});
 926                        }
 927                }
 928                # If this is a revision of the media page for new version
 929                # of a file do one common commit for both file and media page.
 930                # Else do commit only for that page.
 931                print STDERR "$n/", scalar(@$revision_ids), ": Revision #$rev->{revid} of $commit{title}\n";
 932                import_file_revision(\%commit, ($fetch_from == 1), $n_actual, \%mediafile);
 933        }
 934
 935        return $n_actual;
 936}
 937
 938sub error_non_fast_forward {
 939        my $advice = run_git("config --bool advice.pushNonFastForward");
 940        chomp($advice);
 941        if ($advice ne "false") {
 942                # Native git-push would show this after the summary.
 943                # We can't ask it to display it cleanly, so print it
 944                # ourselves before.
 945                print STDERR "To prevent you from losing history, non-fast-forward updates were rejected\n";
 946                print STDERR "Merge the remote changes (e.g. 'git pull') before pushing again. See the\n";
 947                print STDERR "'Note about fast-forwards' section of 'git push --help' for details.\n";
 948        }
 949        print STDOUT "error $_[0] \"non-fast-forward\"\n";
 950        return 0;
 951}
 952
 953sub mw_upload_file {
 954        my $complete_file_name = shift;
 955        my $new_sha1 = shift;
 956        my $extension = shift;
 957        my $file_deleted = shift;
 958        my $summary = shift;
 959        my $newrevid;
 960        my $path = "File:" . $complete_file_name;
 961        my %hashFiles = get_allowed_file_extensions();
 962        if (!exists($hashFiles{$extension})) {
 963                print STDERR "$complete_file_name is not a permitted file on this wiki.\n";
 964                print STDERR "Check the configuration of file uploads in your mediawiki.\n";
 965                return $newrevid;
 966        }
 967        # Deleting and uploading a file requires a priviledged user
 968        if ($file_deleted) {
 969                mw_connect_maybe();
 970                my $query = {
 971                        action => 'delete',
 972                        title => $path,
 973                        reason => $summary
 974                };
 975                if (!$mediawiki->edit($query)) {
 976                        print STDERR "Failed to delete file on remote wiki\n";
 977                        print STDERR "Check your permissions on the remote site. Error code:\n";
 978                        print STDERR $mediawiki->{error}->{code} . ':' . $mediawiki->{error}->{details};
 979                        exit 1;
 980                }
 981        } else {
 982                # Don't let perl try to interpret file content as UTF-8 => use "raw"
 983                my $content = run_git("cat-file blob $new_sha1", "raw");
 984                if ($content ne "") {
 985                        mw_connect_maybe();
 986                        $mediawiki->{config}->{upload_url} =
 987                                "$url/index.php/Special:Upload";
 988                        $mediawiki->edit({
 989                                action => 'upload',
 990                                filename => $complete_file_name,
 991                                comment => $summary,
 992                                file => [undef,
 993                                         $complete_file_name,
 994                                         Content => $content],
 995                                ignorewarnings => 1,
 996                        }, {
 997                                skip_encoding => 1
 998                        } ) || die $mediawiki->{error}->{code} . ':'
 999                                 . $mediawiki->{error}->{details};
1000                        my $last_file_page = $mediawiki->get_page({title => $path});
1001                        $newrevid = $last_file_page->{revid};
1002                        print STDERR "Pushed file: $new_sha1 - $complete_file_name.\n";
1003                } else {
1004                        print STDERR "Empty file $complete_file_name not pushed.\n";
1005                }
1006        }
1007        return $newrevid;
1008}
1009
1010sub mw_push_file {
1011        my $diff_info = shift;
1012        # $diff_info contains a string in this format:
1013        # 100644 100644 <sha1_of_blob_before_commit> <sha1_of_blob_now> <status>
1014        my @diff_info_split = split(/[ \t]/, $diff_info);
1015
1016        # Filename, including .mw extension
1017        my $complete_file_name = shift;
1018        # Commit message
1019        my $summary = shift;
1020        # MediaWiki revision number. Keep the previous one by default,
1021        # in case there's no edit to perform.
1022        my $oldrevid = shift;
1023        my $newrevid;
1024
1025        if ($summary eq EMPTY_MESSAGE) {
1026                $summary = '';
1027        }
1028
1029        my $new_sha1 = $diff_info_split[3];
1030        my $old_sha1 = $diff_info_split[2];
1031        my $page_created = ($old_sha1 eq NULL_SHA1);
1032        my $page_deleted = ($new_sha1 eq NULL_SHA1);
1033        $complete_file_name = mediawiki_clean_filename($complete_file_name);
1034
1035        my ($title, $extension) = $complete_file_name =~ /^(.*)\.([^\.]*)$/;
1036        if (!defined($extension)) {
1037                $extension = "";
1038        }
1039        if ($extension eq "mw") {
1040                my $ns = get_mw_namespace_id_for_page($complete_file_name);
1041                if ($ns && $ns == get_mw_namespace_id("File") && (!$export_media)) {
1042                        print STDERR "Ignoring media file related page: $complete_file_name\n";
1043                        return ($oldrevid, "ok");
1044                }
1045                my $file_content;
1046                if ($page_deleted) {
1047                        # Deleting a page usually requires
1048                        # special privileges. A common
1049                        # convention is to replace the page
1050                        # with this content instead:
1051                        $file_content = DELETED_CONTENT;
1052                } else {
1053                        $file_content = run_git("cat-file blob $new_sha1");
1054                }
1055
1056                mw_connect_maybe();
1057
1058                my $result = $mediawiki->edit( {
1059                        action => 'edit',
1060                        summary => $summary,
1061                        title => $title,
1062                        basetimestamp => $basetimestamps{$oldrevid},
1063                        text => mediawiki_clean($file_content, $page_created),
1064                                  }, {
1065                                          skip_encoding => 1 # Helps with names with accentuated characters
1066                                  });
1067                if (!$result) {
1068                        if ($mediawiki->{error}->{code} == 3) {
1069                                # edit conflicts, considered as non-fast-forward
1070                                print STDERR 'Warning: Error ' .
1071                                    $mediawiki->{error}->{code} .
1072                                    ' from mediwiki: ' . $mediawiki->{error}->{details} .
1073                                    ".\n";
1074                                return ($oldrevid, "non-fast-forward");
1075                        } else {
1076                                # Other errors. Shouldn't happen => just die()
1077                                die 'Fatal: Error ' .
1078                                    $mediawiki->{error}->{code} .
1079                                    ' from mediwiki: ' . $mediawiki->{error}->{details};
1080                        }
1081                }
1082                $newrevid = $result->{edit}->{newrevid};
1083                print STDERR "Pushed file: $new_sha1 - $title\n";
1084        } elsif ($export_media) {
1085                $newrevid = mw_upload_file($complete_file_name, $new_sha1,
1086                                           $extension, $page_deleted,
1087                                           $summary);
1088        } else {
1089                print STDERR "Ignoring media file $title\n";
1090        }
1091        $newrevid = ($newrevid or $oldrevid);
1092        return ($newrevid, "ok");
1093}
1094
1095sub mw_push {
1096        # multiple push statements can follow each other
1097        my @refsspecs = (shift, get_more_refs("push"));
1098        my $pushed;
1099        for my $refspec (@refsspecs) {
1100                my ($force, $local, $remote) = $refspec =~ /^(\+)?([^:]*):([^:]*)$/
1101                    or die("Invalid refspec for push. Expected <src>:<dst> or +<src>:<dst>");
1102                if ($force) {
1103                        print STDERR "Warning: forced push not allowed on a MediaWiki.\n";
1104                }
1105                if ($local eq "") {
1106                        print STDERR "Cannot delete remote branch on a MediaWiki\n";
1107                        print STDOUT "error $remote cannot delete\n";
1108                        next;
1109                }
1110                if ($remote ne "refs/heads/master") {
1111                        print STDERR "Only push to the branch 'master' is supported on a MediaWiki\n";
1112                        print STDOUT "error $remote only master allowed\n";
1113                        next;
1114                }
1115                if (mw_push_revision($local, $remote)) {
1116                        $pushed = 1;
1117                }
1118        }
1119
1120        # Notify Git that the push is done
1121        print STDOUT "\n";
1122
1123        if ($pushed && $dumb_push) {
1124                print STDERR "Just pushed some revisions to MediaWiki.\n";
1125                print STDERR "The pushed revisions now have to be re-imported, and your current branch\n";
1126                print STDERR "needs to be updated with these re-imported commits. You can do this with\n";
1127                print STDERR "\n";
1128                print STDERR "  git pull --rebase\n";
1129                print STDERR "\n";
1130        }
1131        return;
1132}
1133
1134sub mw_push_revision {
1135        my $local = shift;
1136        my $remote = shift; # actually, this has to be "refs/heads/master" at this point.
1137        my $last_local_revid = get_last_local_revision();
1138        print STDERR ".\n"; # Finish sentence started by get_last_local_revision()
1139        my $last_remote_revid = get_last_remote_revision();
1140        my $mw_revision = $last_remote_revid;
1141
1142        # Get sha1 of commit pointed by local HEAD
1143        my $HEAD_sha1 = run_git("rev-parse $local 2>/dev/null"); chomp($HEAD_sha1);
1144        # Get sha1 of commit pointed by remotes/$remotename/master
1145        my $remoteorigin_sha1 = run_git("rev-parse refs/remotes/$remotename/master 2>/dev/null");
1146        chomp($remoteorigin_sha1);
1147
1148        if ($last_local_revid > 0 &&
1149            $last_local_revid < $last_remote_revid) {
1150                return error_non_fast_forward($remote);
1151        }
1152
1153        if ($HEAD_sha1 eq $remoteorigin_sha1) {
1154                # nothing to push
1155                return 0;
1156        }
1157
1158        # Get every commit in between HEAD and refs/remotes/origin/master,
1159        # including HEAD and refs/remotes/origin/master
1160        my @commit_pairs = ();
1161        if ($last_local_revid > 0) {
1162                my $parsed_sha1 = $remoteorigin_sha1;
1163                # Find a path from last MediaWiki commit to pushed commit
1164                print STDERR "Computing path from local to remote ...\n";
1165                my @local_ancestry = split(/\n/, run_git("rev-list --boundary --parents $local ^$parsed_sha1"));
1166                my %local_ancestry;
1167                foreach my $line (@local_ancestry) {
1168                        if (my ($child, $parents) = $line =~ m/^-?([a-f0-9]+) ([a-f0-9 ]+)/) {
1169                                foreach my $parent (split(' ', $parents)) {
1170                                        $local_ancestry{$parent} = $child;
1171                                }
1172                        } elsif (!$line =~ m/^([a-f0-9]+)/) {
1173                                die "Unexpected output from git rev-list: $line";
1174                        }
1175                }
1176                while ($parsed_sha1 ne $HEAD_sha1) {
1177                        my $child = $local_ancestry{$parsed_sha1};
1178                        if (!$child) {
1179                                printf STDERR "Cannot find a path in history from remote commit to last commit\n";
1180                                return error_non_fast_forward($remote);
1181                        }
1182                        push(@commit_pairs, [$parsed_sha1, $child]);
1183                        $parsed_sha1 = $child;
1184                }
1185        } else {
1186                # No remote mediawiki revision. Export the whole
1187                # history (linearized with --first-parent)
1188                print STDERR "Warning: no common ancestor, pushing complete history\n";
1189                my $history = run_git("rev-list --first-parent --children $local");
1190                my @history = split(/\n/, $history);
1191                @history = @history[1..$#history];
1192                foreach my $line (reverse @history) {
1193                        my @commit_info_split = split(/ |\n/, $line);
1194                        push(@commit_pairs, \@commit_info_split);
1195                }
1196        }
1197
1198        foreach my $commit_info_split (@commit_pairs) {
1199                my $sha1_child = @{$commit_info_split}[0];
1200                my $sha1_commit = @{$commit_info_split}[1];
1201                my $diff_infos = run_git("diff-tree -r --raw -z $sha1_child $sha1_commit");
1202                # TODO: we could detect rename, and encode them with a #redirect on the wiki.
1203                # TODO: for now, it's just a delete+add
1204                my @diff_info_list = split(/\0/, $diff_infos);
1205                # Keep the subject line of the commit message as mediawiki comment for the revision
1206                my $commit_msg = run_git("log --no-walk --format=\"%s\" $sha1_commit");
1207                chomp($commit_msg);
1208                # Push every blob
1209                while (@diff_info_list) {
1210                        my $status;
1211                        # git diff-tree -z gives an output like
1212                        # <metadata>\0<filename1>\0
1213                        # <metadata>\0<filename2>\0
1214                        # and we've split on \0.
1215                        my $info = shift(@diff_info_list);
1216                        my $file = shift(@diff_info_list);
1217                        ($mw_revision, $status) = mw_push_file($info, $file, $commit_msg, $mw_revision);
1218                        if ($status eq "non-fast-forward") {
1219                                # we may already have sent part of the
1220                                # commit to MediaWiki, but it's too
1221                                # late to cancel it. Stop the push in
1222                                # the middle, but still give an
1223                                # accurate error message.
1224                                return error_non_fast_forward($remote);
1225                        }
1226                        if ($status ne "ok") {
1227                                die("Unknown error from mw_push_file()");
1228                        }
1229                }
1230                unless ($dumb_push) {
1231                        run_git("notes --ref=$remotename/mediawiki add -f -m \"mediawiki_revision: $mw_revision\" $sha1_commit");
1232                        run_git("update-ref -m \"Git-MediaWiki push\" refs/mediawiki/$remotename/master $sha1_commit $sha1_child");
1233                }
1234        }
1235
1236        print STDOUT "ok $remote\n";
1237        return 1;
1238}
1239
1240sub get_allowed_file_extensions {
1241        mw_connect_maybe();
1242
1243        my $query = {
1244                action => 'query',
1245                meta => 'siteinfo',
1246                siprop => 'fileextensions'
1247                };
1248        my $result = $mediawiki->api($query);
1249        my @file_extensions= map $_->{ext},@{$result->{query}->{fileextensions}};
1250        my %hashFile = map {$_ => 1}@file_extensions;
1251
1252        return %hashFile;
1253}
1254
1255# In memory cache for MediaWiki namespace ids.
1256my %namespace_id;
1257
1258# Namespaces whose id is cached in the configuration file
1259# (to avoid duplicates)
1260my %cached_mw_namespace_id;
1261
1262# Return MediaWiki id for a canonical namespace name.
1263# Ex.: "File", "Project".
1264sub get_mw_namespace_id {
1265        mw_connect_maybe();
1266        my $name = shift;
1267
1268        if (!exists $namespace_id{$name}) {
1269                # Look at configuration file, if the record for that namespace is
1270                # already cached. Namespaces are stored in form:
1271                # "Name_of_namespace:Id_namespace", ex.: "File:6".
1272                my @temp = split(/[\n]/, run_git("config --get-all remote."
1273                                                . $remotename .".namespaceCache"));
1274                chomp(@temp);
1275                foreach my $ns (@temp) {
1276                        my ($n, $id) = split(/:/, $ns);
1277                        if ($id eq 'notANameSpace') {
1278                                $namespace_id{$n} = {is_namespace => 0};
1279                        } else {
1280                                $namespace_id{$n} = {is_namespace => 1, id => $id};
1281                        }
1282                        $cached_mw_namespace_id{$n} = 1;
1283                }
1284        }
1285
1286        if (!exists $namespace_id{$name}) {
1287                print STDERR "Namespace $name not found in cache, querying the wiki ...\n";
1288                # NS not found => get namespace id from MW and store it in
1289                # configuration file.
1290                my $query = {
1291                        action => 'query',
1292                        meta => 'siteinfo',
1293                        siprop => 'namespaces'
1294                };
1295                my $result = $mediawiki->api($query);
1296
1297                while (my ($id, $ns) = each(%{$result->{query}->{namespaces}})) {
1298                        if (defined($ns->{id}) && defined($ns->{canonical})) {
1299                                $namespace_id{$ns->{canonical}} = {is_namespace => 1, id => $ns->{id}};
1300                                if ($ns->{'*'}) {
1301                                        # alias (e.g. french Fichier: as alias for canonical File:)
1302                                        $namespace_id{$ns->{'*'}} = {is_namespace => 1, id => $ns->{id}};
1303                                }
1304                        }
1305                }
1306        }
1307
1308        my $ns = $namespace_id{$name};
1309        my $id;
1310
1311        unless (defined $ns) {
1312                print STDERR "No such namespace $name on MediaWiki.\n";
1313                $ns = {is_namespace => 0};
1314                $namespace_id{$name} = $ns;
1315        }
1316
1317        if ($ns->{is_namespace}) {
1318                $id = $ns->{id};
1319        }
1320
1321        # Store "notANameSpace" as special value for inexisting namespaces
1322        my $store_id = ($id || 'notANameSpace');
1323
1324        # Store explicitely requested namespaces on disk
1325        if (!exists $cached_mw_namespace_id{$name}) {
1326                run_git("config --add remote.". $remotename
1327                        .".namespaceCache \"". $name .":". $store_id ."\"");
1328                $cached_mw_namespace_id{$name} = 1;
1329        }
1330        return $id;
1331}
1332
1333sub get_mw_namespace_id_for_page {
1334        if (my ($namespace) = $_[0] =~ /^([^:]*):/) {
1335                return get_mw_namespace_id($namespace);
1336        } else {
1337                return;
1338        }
1339}