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  */
  22
  23 /**
  24  * TODO: Perhaps make this file into a Metadata class, with static methods (declared
  25  * as private where indicated), to move these functions out of the global namespace?
  26  */
  27 define('RDF_TYPE_PREFS', "application/rdf+xml,text/xml;q=0.7,application/xml;q=0.5,text/rdf;q=0.1");
  28
  29 function wfDublinCoreRdf($article) {
  30
  31         $url = dcReallyFullUrl($article->mTitle);
  32
  33         if (rdfSetup()) {
  34                 dcPrologue($url);
  35                 dcBasics($article);
  36                 dcEpilogue();
  37         }
  38 }
  39
  40 function wfCreativeCommonsRdf($article) {
  41
  42         if (rdfSetup()) {
  43                 global $wgRightsUrl;
  44
  45                 $url = dcReallyFullUrl($article->mTitle);
  46
  47                 ccPrologue();
  48                 ccSubPrologue('Work', $url);
  49                 dcBasics($article);
  50                 if (isset($wgRightsUrl)) {
  51                         $url = htmlspecialchars( $wgRightsUrl );
  52                         print "    <cc:license rdf:resource=\"$url\" />\n";
  53                 }
  54
  55                 ccSubEpilogue('Work');
  56
  57                 if (isset($wgRightsUrl)) {
  58                         $terms = ccGetTerms($wgRightsUrl);
  59                         if ($terms) {
  60                                 ccSubPrologue('License', $wgRightsUrl);
  61                                 ccLicense($terms);
  62                                 ccSubEpilogue('License');
  63                         }
  64                 }
  65         }
  66
  67         ccEpilogue();
  68 }
  69
  70 /**
  71  * @private
  72  */
  73 function rdfSetup() {
  74         global $wgOut, $_SERVER;
  75
  76         if( !isset($_SERVER['HTTP_ACCEPT']) ) {
  77                 $_SERVER['HTTP_ACCEPT'] = '';
  78         }
  79
  80         $rdftype = wfNegotiateType(wfAcceptToPrefs($_SERVER['HTTP_ACCEPT']), wfAcceptToPrefs(RDF_TYPE_PREFS));
  81
  82         if (!$rdftype) {
  83                 wfHttpError(406, "Not Acceptable", wfMsg("notacceptable"));
  84                 return false;
  85         } else {
  86                 $wgOut->disable();
  87                 header( "Content-type: {$rdftype}; charset=utf-8" );
  88                 $wgOut->sendCacheControl();
  89                 return true;
  90         }
  91 }
  92
  93 /**
  94  * @private
  95  */
  96 function dcPrologue($url) {
  97         global $wgOutputEncoding;
  98
  99         $url = htmlspecialchars( $url );
 100         print "<" . "?xml version=\"1.0\" encoding=\"{$wgOutputEncoding}\" ?" . ">
 101
 102                                                                                                                                                           <!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\">
 103
 104                                                                                                                                                           <rdf:RDF xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\"
 105                                                                                                                                                           xmlns:dc=\"http://purl.org/dc/elements/1.1/\">
 106                                                                                                                                                           <rdf:Description rdf:about=\"$url\">
 107                                                                                                                                                           ";
 108 }
 109
 110 /**
 111  * @private
 112  */
 113 function dcEpilogue() {
 114         print "
 115                         </rdf:Description>
 116                         </rdf:RDF>
 117                         ";
 118 }
 119
 120 /**
 121  * @private
 122  */
 123 function dcBasics($article) {
 124         global $wgContLanguageCode, $wgSitename;
 125
 126         dcElement('title', $article->mTitle->getText());
 127         dcPageOrString('publisher', wfMsg('aboutpage'), $wgSitename);
 128         dcElement('language', $wgContLanguageCode);
 129         dcElement('type', 'Text');
 130         dcElement('format', 'text/html');
 131         dcElement('identifier', dcReallyFullUrl($article->mTitle));
 132         dcElement('date', dcDate($article->getTimestamp()));
 133
 134         $last_editor = $article->getUser();
 135
 136         if ($last_editor == 0) {
 137                 dcPerson('creator', 0);
 138         } else {
 139                 dcPerson('creator', $last_editor, $article->getUserText(),
 140                                  User::whoIsReal($last_editor));
 141         }
 142
 143         $contributors = $article->getContributors();
 144
 145         foreach ($contributors as $user_parts) {
 146                 dcPerson('contributor', $user_parts[0], $user_parts[1], $user_parts[2]);
 147         }
 148
 149         dcRights();
 150 }
 151
 152 /**
 153  * @private
 154  */
 155 function ccPrologue() {
 156         global $wgOutputEncoding;
 157
 158         echo "<" . "?xml version='1.0'  encoding='{$wgOutputEncoding}' ?" . ">
 159
 160                                                                                                                                                   <rdf:RDF xmlns:cc=\"http://web.resource.org/cc/\"
 161                                                                                                                                                   xmlns:dc=\"http://purl.org/dc/elements/1.1/\"
 162                                                                                                                                                   xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\">
 163                                                                                                                                                   ";
 164 }
 165
 166 /**
 167  * @private
 168  */
 169 function ccSubPrologue($type, $url) {
 170         $url = htmlspecialchars( $url );
 171         echo "  <cc:{$type} rdf:about=\"{$url}\">\n";
 172 }
 173
 174 /**
 175  * @private
 176  */
 177 function ccSubEpilogue($type) {
 178         echo "  </cc:{$type}>\n";
 179 }
 180
 181 /**
 182  * @private
 183  */
 184 function ccLicense($terms) {
 185
 186         foreach ($terms as $term) {
 187                 switch ($term) {
 188                  case 're':
 189                         ccTerm('permits', 'Reproduction'); break;
 190                  case 'di':
 191                         ccTerm('permits', 'Distribution'); break;
 192                  case 'de':
 193                         ccTerm('permits', 'DerivativeWorks'); break;
 194                  case 'nc':
 195                         ccTerm('prohibits', 'CommercialUse'); break;
 196                  case 'no':
 197                         ccTerm('requires', 'Notice'); break;
 198                  case 'by':
 199                         ccTerm('requires', 'Attribution'); break;
 200                  case 'sa':
 201                         ccTerm('requires', 'ShareAlike'); break;
 202                  case 'sc':
 203                         ccTerm('requires', 'SourceCode'); break;
 204                 }
 205         }
 206 }
 207
 208 /**
 209  * @private
 210  */
 211 function ccTerm($term, $name) {
 212         print "    <cc:{$term} rdf:resource=\"http://web.resource.org/cc/{$name}\" />\n";
 213 }
 214
 215 /**
 216  * @private
 217  */
 218 function ccEpilogue() {
 219         echo "</rdf:RDF>\n";
 220 }
 221
 222 /**
 223  * @private
 224  */
 225 function dcElement($name, $value) {
 226         $value = htmlspecialchars( $value );
 227         print "    <dc:{$name}>{$value}</dc:{$name}>\n";
 228 }
 229
 230 /**
 231  * @private
 232  */
 233 function dcDate($timestamp) {
 234         return substr($timestamp, 0, 4) . '-'
 235           . substr($timestamp, 4, 2) . '-'
 236           . substr($timestamp, 6, 2);
 237 }
 238
 239 /**
 240  * @private
 241  */
 242 function dcReallyFullUrl($title) {
 243         return $title->getFullURL();
 244 }
 245
 246 /**
 247  * @private
 248  */
 249 function dcPageOrString($name, $page, $str) {
 250         $nt = Title::newFromText($page);
 251
 252         if (!$nt || $nt->getArticleID() == 0) {
 253                 dcElement($name, $str);
 254         } else {
 255                 dcPage($name, $nt);
 256         }
 257 }
 258
 259 /**
 260  * @private
 261  */
 262 function dcPage($name, $title) {
 263         dcUrl($name, dcReallyFullUrl($title));
 264 }
 265
 266 /**
 267  * @private
 268  */
 269 function dcUrl($name, $url) {
 270         $url = htmlspecialchars( $url );
 271         print "    <dc:{$name} rdf:resource=\"{$url}\" />\n";
 272 }
 273
 274 /**
 275  * @private
 276  */
 277 function dcPerson($name, $id, $user_name='', $user_real_name='') {
 278         global $wgContLang;
 279
 280         if ($id == 0) {
 281                 dcElement($name, wfMsg('anonymous'));
 282         } else if ( !empty($user_real_name) ) {
 283                 dcElement($name, $user_real_name);
 284         } else {
 285                 # XXX: This shouldn't happen.
 286                 if( empty( $user_name ) ) {
 287                         $user_name = User::whoIs($id);
 288                 }
 289                 dcPageOrString($name, $wgContLang->getNsText(NS_USER) . ':' . $user_name, wfMsg('siteuser', $user_name));
 290         }
 291 }
 292
 293 /**
 294  * Takes an arg, for future enhancement with different rights for
 295  * different pages.
 296  * @private
 297  */
 298 function dcRights() {
 299
 300         global $wgRightsPage, $wgRightsUrl, $wgRightsText;
 301
 302         if (isset($wgRightsPage) &&
 303                 ($nt = Title::newFromText($wgRightsPage))
 304                 && ($nt->getArticleID() != 0)) {
 305                 dcPage('rights', $nt);
 306         } else if (isset($wgRightsUrl)) {
 307                 dcUrl('rights', $wgRightsUrl);
 308         } else if (isset($wgRightsText)) {
 309                 dcElement('rights', $wgRightsText);
 310         }
 311 }
 312
 313 /**
 314  * @private
 315  */
 316 function ccGetTerms($url) {
 317         global $wgLicenseTerms;
 318
 319         if (isset($wgLicenseTerms)) {
 320                 return $wgLicenseTerms;
 321         } else {
 322                 $known = getKnownLicenses();
 323                 if( isset( $known[$url] ) ) {
 324                         return $known[$url];
 325                 } else {
 326                         return array();
 327                 }
 328         }
 329 }
 330
 331 /**
 332  * @private
 333  */
 334 function getKnownLicenses() {
 335
 336         $ccLicenses = array('by', 'by-nd', 'by-nd-nc', 'by-nc',
 337                                                 'by-nc-sa', 'by-sa');
 338         $ccVersions = array('1.0', '2.0');
 339         $knownLicenses = array();
 340
 341         foreach ($ccVersions as $version) {
 342                 foreach ($ccLicenses as $license) {
 343                         if( $version == '2.0' && substr( $license, 0, 2) != 'by' ) {
 344                                 # 2.0 dropped the non-attribs licenses
 345                                 continue;
 346                         }
 347                         $lurl = "http://creativecommons.org/licenses/{$license}/{$version}/";
 348                         $knownLicenses[$lurl] = explode('-', $license);
 349                         $knownLicenses[$lurl][] = 're';
 350                         $knownLicenses[$lurl][] = 'di';
 351                         $knownLicenses[$lurl][] = 'no';
 352                         if (!in_array('nd', $knownLicenses[$lurl])) {
 353                                 $knownLicenses[$lurl][] = 'de';
 354                         }
 355                 }
 356         }
 357
 358         /* Handle the GPL and LGPL, too. */
 359
 360         $knownLicenses['http://creativecommons.org/licenses/GPL/2.0/'] =
 361           array('de', 're', 'di', 'no', 'sa', 'sc');
 362         $knownLicenses['http://creativecommons.org/licenses/LGPL/2.1/'] =
 363           array('de', 're', 'di', 'no', 'sa', 'sc');
 364         $knownLicenses['http://www.gnu.org/copyleft/fdl.html'] =
 365           array('de', 're', 'di', 'no', 'sa', 'sc');
 366
 367         return $knownLicenses;
 368 }
 369
 370 ?>