includes/Metadata.php

   1 <?php
   2 /**
   3  * Metadata.php -- provides DublinCore and CreativeCommons metadata
   4  * Copyright 2004, Evan Prodromou <evan@wikitravel.org>.
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
  19  *
  20  * @author Evan Prodromou <evan@wikitravel.org>
  21  * @package MediaWiki
  22  */
  23
  24 /**
  25  * TODO: Perhaps make this file into a Metadata class, with static methods (declared
  26  * as private where indicated), to move these functions out of the global namespace?
  27  */
  28 define('RDF_TYPE_PREFS', "application/rdf+xml,text/xml;q=0.7,application/xml;q=0.5,text/rdf;q=0.1");
  29
  30 function wfDublinCoreRdf($article) {
  31
  32         $url = dcReallyFullUrl($article->mTitle);
  33
  34         if (rdfSetup()) {
  35                 dcPrologue($url);
  36                 dcBasics($article);
  37                 dcEpilogue();
  38         }
  39 }
  40
  41 function wfCreativeCommonsRdf($article) {
  42
  43         if (rdfSetup()) {
  44                 global $wgRightsUrl;
  45
  46                 $url = dcReallyFullUrl($article->mTitle);
  47
  48                 ccPrologue();
  49                 ccSubPrologue('Work', $url);
  50                 dcBasics($article);
  51                 if (isset($wgRightsUrl)) {
  52                         $url = htmlspecialchars( $wgRightsUrl );
  53                         print "    <cc:license rdf:resource=\"$url\" />\n";
  54                 }
  55
  56                 ccSubEpilogue('Work');
  57
  58                 if (isset($wgRightsUrl)) {
  59                         $terms = ccGetTerms($wgRightsUrl);
  60                         if ($terms) {
  61                                 ccSubPrologue('License', $wgRightsUrl);
  62                                 ccLicense($terms);
  63                                 ccSubEpilogue('License');
  64                         }
  65                 }
  66         }
  67
  68         ccEpilogue();
  69 }
  70
  71 /**
  72  * @private
  73  */
  74 function rdfSetup() {
  75         global $wgOut, $_SERVER;
  76
  77         $rdftype = wfNegotiateType(wfAcceptToPrefs($_SERVER['HTTP_ACCEPT']), wfAcceptToPrefs(RDF_TYPE_PREFS));
  78
  79         if (!$rdftype) {
  80                 wfHttpError(406, "Not Acceptable", wfMsg("notacceptable"));
  81                 return false;
  82         } else {
  83                 $wgOut->disable();
  84                 header( "Content-type: {$rdftype}" );
  85                 $wgOut->sendCacheControl();
  86                 return true;
  87         }
  88 }
  89
  90 /**
  91  * @private
  92  */
  93 function dcPrologue($url) {
  94         global $wgOutputEncoding;
  95
  96         $url = htmlspecialchars( $url );
  97         print "<" . "?xml version=\"1.0\" encoding=\"{$wgOutputEncoding}\" ?" . ">
  98
  99                                                                                                                                                           <!DOCTYPE rdf:RDF PUBLIC \"-//DUBLIN CORE//DCMES DTD 2002/07/31//EN\" \"http://dublincore.org/documents/2002/07/31/dcmes-xml/dcmes-xml-dtd.dtd\">
 100
 101                                                                                                                                                           <rdf:RDF xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\"
 102                                                                                                                                                           xmlns:dc=\"http://purl.org/dc/elements/1.1/\">
 103                                                                                                                                                           <rdf:Description rdf:about=\"$url\">
 104                                                                                                                                                           ";
 105 }
 106
 107 /**
 108  * @private
 109  */
 110 function dcEpilogue() {
 111         print "
 112                         </rdf:Description>
 113                         </rdf:RDF>
 114                         ";
 115 }
 116
 117 /**
 118  * @private
 119  */
 120 function dcBasics($article) {
 121         global $wgContLanguageCode, $wgSitename;
 122
 123         dcElement('title', $article->mTitle->getText());
 124         dcPageOrString('publisher', wfMsg('aboutpage'), $wgSitename);
 125         dcElement('language', $wgContLanguageCode);
 126         dcElement('type', 'Text');
 127         dcElement('format', 'text/html');
 128         dcElement('identifier', dcReallyFullUrl($article->mTitle));
 129         dcElement('date', dcDate($article->getTimestamp()));
 130
 131         $last_editor = $article->getUser();
 132
 133         if ($last_editor == 0) {
 134                 dcPerson('creator', 0);
 135         } else {
 136                 dcPerson('creator', $last_editor, $article->getUserText(),
 137                                  User::whoIsReal($last_editor));
 138         }
 139
 140         $contributors = $article->getContributors();
 141
 142         foreach ($contributors as $user_parts) {
 143                 dcPerson('contributor', $user_parts[0], $user_parts[1], $user_parts[2]);
 144         }
 145
 146         dcRights();
 147 }
 148
 149 /**
 150  * @private
 151  */
 152 function ccPrologue() {
 153         global $wgOutputEncoding;
 154
 155         echo "<" . "?xml version='1.0'  encoding='{$wgOutputEncoding}' ?" . ">
 156
 157                                                                                                                                                   <rdf:RDF xmlns:cc=\"http://web.resource.org/cc/\"
 158                                                                                                                                                   xmlns:dc=\"http://purl.org/dc/elements/1.1/\"
 159                                                                                                                                                   xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\">
 160                                                                                                                                                   ";
 161 }
 162
 163 /**
 164  * @private
 165  */
 166 function ccSubPrologue($type, $url) {
 167         $url = htmlspecialchars( $url );
 168         echo "  <cc:{$type} rdf:about=\"{$url}\">\n";
 169 }
 170
 171 /**
 172  * @private
 173  */
 174 function ccSubEpilogue($type) {
 175         echo "  </cc:{$type}>\n";
 176 }
 177
 178 /**
 179  * @private
 180  */
 181 function ccLicense($terms) {
 182
 183         foreach ($terms as $term) {
 184                 switch ($term) {
 185                  case 're':
 186                         ccTerm('permits', 'Reproduction'); break;
 187                  case 'di':
 188                         ccTerm('permits', 'Distribution'); break;
 189                  case 'de':
 190                         ccTerm('permits', 'DerivativeWorks'); break;
 191                  case 'nc':
 192                         ccTerm('prohibits', 'CommercialUse'); break;
 193                  case 'no':
 194                         ccTerm('requires', 'Notice'); break;
 195                  case 'by':
 196                         ccTerm('requires', 'Attribution'); break;
 197                  case 'sa':
 198                         ccTerm('requires', 'ShareAlike'); break;
 199                  case 'sc':
 200                         ccTerm('requires', 'SourceCode'); break;
 201                 }
 202         }
 203 }
 204
 205 /**
 206  * @private
 207  */
 208 function ccTerm($term, $name) {
 209         print "    <cc:{$term} rdf:resource=\"http://web.resource.org/cc/{$name}\" />\n";
 210 }
 211
 212 /**
 213  * @private
 214  */
 215 function ccEpilogue() {
 216         echo "</rdf:RDF>\n";
 217 }
 218
 219 /**
 220  * @private
 221  */
 222 function dcElement($name, $value) {
 223         $value = htmlspecialchars( $value );
 224         print "    <dc:{$name}>{$value}</dc:{$name}>\n";
 225 }
 226
 227 /**
 228  * @private
 229  */
 230 function dcDate($timestamp) {
 231         return substr($timestamp, 0, 4) . '-'
 232           . substr($timestamp, 4, 2) . '-'
 233           . substr($timestamp, 6, 2);
 234 }
 235
 236 /**
 237  * @private
 238  */
 239 function dcReallyFullUrl($title) {
 240         return $title->getFullURL();
 241 }
 242
 243 /**
 244  * @private
 245  */
 246 function dcPageOrString($name, $page, $str) {
 247         $nt = Title::newFromText($page);
 248
 249         if (!$nt || $nt->getArticleID() == 0) {
 250                 dcElement($name, $str);
 251         } else {
 252                 dcPage($name, $nt);
 253         }
 254 }
 255
 256 /**
 257  * @private
 258  */
 259 function dcPage($name, $title) {
 260         dcUrl($name, dcReallyFullUrl($title));
 261 }
 262
 263 /**
 264  * @private
 265  */
 266 function dcUrl($name, $url) {
 267         $url = htmlspecialchars( $url );
 268         print "    <dc:{$name} rdf:resource=\"{$url}\" />\n";
 269 }
 270
 271 /**
 272  * @private
 273  */
 274 function dcPerson($name, $id, $user_name='', $user_real_name='') {
 275         global $wgContLang;
 276
 277         if ($id == 0) {
 278                 dcElement($name, wfMsg('anonymous'));
 279         } else if ( !empty($user_real_name) ) {
 280                 dcElement($name, $user_real_name);
 281         } else {
 282                 # XXX: This shouldn't happen.
 283                 if( empty( $user_name ) ) {
 284                         $user_name = User::whoIs($id);
 285                 }
 286                 dcPageOrString($name, $wgContLang->getNsText(NS_USER) . ':' . $user_name, wfMsg('siteuser', $user_name));
 287         }
 288 }
 289
 290 /**
 291  * Takes an arg, for future enhancement with different rights for
 292  * different pages.
 293  * @private
 294  */
 295 function dcRights() {
 296
 297         global $wgRightsPage, $wgRightsUrl, $wgRightsText;
 298
 299         if (isset($wgRightsPage) &&
 300                 ($nt = Title::newFromText($wgRightsPage))
 301                 && ($nt->getArticleID() != 0)) {
 302                 dcPage('rights', $nt);
 303         } else if (isset($wgRightsUrl)) {
 304                 dcUrl('rights', $wgRightsUrl);
 305         } else if (isset($wgRightsText)) {
 306                 dcElement('rights', $wgRightsText);
 307         }
 308 }
 309
 310 /**
 311  * @private
 312  */
 313 function ccGetTerms($url) {
 314         global $wgLicenseTerms;
 315
 316         if (isset($wgLicenseTerms)) {
 317                 return $wgLicenseTerms;
 318         } else {
 319                 $known = getKnownLicenses();
 320                 if( isset( $known[$url] ) ) {
 321                         return $known[$url];
 322                 } else {
 323                         return array();
 324                 }
 325         }
 326 }
 327
 328 /**
 329  * @private
 330  */
 331 function getKnownLicenses() {
 332
 333         $ccLicenses = array('by', 'by-nd', 'by-nd-nc', 'by-nc',
 334                                                 'by-nc-sa', 'by-sa');
 335         $ccVersions = array('1.0', '2.0');
 336         $knownLicenses = array();
 337
 338         foreach ($ccVersions as $version) {
 339                 foreach ($ccLicenses as $license) {
 340                         if( $version == '2.0' && substr( $license, 0, 2) != 'by' ) {
 341                                 # 2.0 dropped the non-attribs licenses
 342                                 continue;
 343                         }
 344                         $lurl = "http://creativecommons.org/licenses/{$license}/{$version}/";
 345                         $knownLicenses[$lurl] = explode('-', $license);
 346                         $knownLicenses[$lurl][] = 're';
 347                         $knownLicenses[$lurl][] = 'di';
 348                         $knownLicenses[$lurl][] = 'no';
 349                         if (!in_array('nd', $knownLicenses[$lurl])) {
 350                                 $knownLicenses[$lurl][] = 'de';
 351                         }
 352                 }
 353         }
 354
 355         /* Handle the GPL and LGPL, too. */
 356
 357         $knownLicenses['http://creativecommons.org/licenses/GPL/2.0/'] =
 358           array('de', 're', 'di', 'no', 'sa', 'sc');
 359         $knownLicenses['http://creativecommons.org/licenses/LGPL/2.1/'] =
 360           array('de', 're', 'di', 'no', 'sa', 'sc');
 361         $knownLicenses['http://www.gnu.org/copyleft/fdl.html'] =
 362           array('de', 're', 'di', 'no', 'sa', 'sc');
 363
 364         return $knownLicenses;
 365 }
 366
 367 ?>