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