includes/Metadata.php

   1 <?php
   2 /* Metadata.php -- provides DublinCore and CreativeCommons metadata
   3  * Copyright 2004, Evan Prodromou <evan@wikitravel.org>.
   4  *
   5  *  This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program; if not, write to the Free Software
  17  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  */
  19
  20 define("RDF_TYPE_PREFS", "application/rdf+xml,text/xml;q=0.7,application/xml;q=0.5,text/rdf;q=0.1");
  21
  22 function wfDublinCoreRdf($article) {
  23
  24         $url = dcReallyFullUrl($article->mTitle);
  25
  26         if (rdfSetup()) {
  27                 dcPrologue($url);
  28                 dcBasics($article);
  29                 dcEpilogue();
  30         }
  31 }
  32
  33 function wfCreativeCommonsRdf($article) {
  34
  35         if (rdfSetup()) {
  36                 global $wgRightsUrl;
  37
  38                 $url = dcReallyFullUrl($article->mTitle);
  39
  40                 ccPrologue();
  41                 ccSubPrologue('Work', $url);
  42                 dcBasics($article);
  43                 if (isset($wgRightsUrl)) {
  44                         $url = htmlspecialchars( $wgRightsUrl );
  45                         print "    <cc:license rdf:resource=\"$url\" />\n";
  46                 }
  47
  48                 ccSubEpilogue('Work');
  49
  50                 if (isset($wgRightsUrl)) {
  51                         $terms = ccGetTerms($wgRightsUrl);
  52                         if ($terms) {
  53                                 ccSubPrologue('License', $wgRightsUrl);
  54                                 ccLicense($terms);
  55                                 ccSubEpilogue('License');
  56                         }
  57                 }
  58         }
  59
  60         ccEpilogue();
  61 }
  62
  63 /* private */ function rdfSetup() {
  64         global $wgOut, $wgRdfMimeType, $_SERVER;
  65
  66         $rdftype = wfNegotiateType(wfAcceptToPrefs($_SERVER['HTTP_ACCEPT']), wfAcceptToPrefs(RDF_TYPE_PREFS));
  67
  68         if (!$rdftype) {
  69                 wfHttpError(406, "Not Acceptable", wfMsg("notacceptable"));
  70                 return false;
  71         } else {
  72                 $wgOut->disable();
  73                 header( "Content-type: {$rdftype}" );
  74                 $wgOut->sendCacheControl();
  75                 return true;
  76         }
  77 }
  78
  79 /* private */ function dcPrologue($url) {
  80         global $wgOutputEncoding;
  81
  82         $url = htmlspecialchars( $url );
  83         print "<" . "?xml version=\"1.0\" encoding=\"{$wgOutputEncoding}\" ?" . ">
  84
  85 <!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\">
  86
  87 <rdf:RDF xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\"
  88          xmlns:dc=\"http://purl.org/dc/elements/1.1/\">
  89   <rdf:Description rdf:about=\"$url\">
  90 ";
  91 }
  92
  93 /* private */ function dcEpilogue() {
  94         print "
  95   </rdf:Description>
  96 </rdf:RDF>
  97 ";
  98 }
  99
 100 /* private */ function dcBasics($article) {
 101         global $wgLanguageCode, $wgSitename;
 102
 103         dcElement('title', $article->mTitle->getText());
 104         dcPageOrString('publisher', wfMsg('aboutpage'), $wgSitename);
 105         dcElement('language', $wgLanguageCode);
 106         dcElement('type', 'Text');
 107         dcElement('format', 'text/html');
 108         dcElement('identifier', dcReallyFullUrl($article->mTitle));
 109         dcElement('date', dcDate($article->getTimestamp()));
 110         dcPerson('creator', $article->getUser());
 111
 112         $contributors = dcContributors($article->mTitle);
 113
 114         foreach ($contributors as $cid) {
 115                 dcPerson('contributor', $cid);
 116         }
 117
 118         dcRights($article);
 119 }
 120
 121 /* private */ function ccPrologue() {
 122         global $wgOutputEncoding;
 123
 124         echo "<" . "?xml version='1.0'  encoding='{$wgOutputEncoding}' ?" . ">
 125
 126 <rdf:RDF xmlns:cc=\"http://web.resource.org/cc/\"
 127          xmlns:dc=\"http://purl.org/dc/elements/1.1/\"
 128          xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\">
 129 ";
 130 }
 131
 132 /* private */ function ccSubPrologue($type, $url) {
 133         $url = htmlspecialchars( $url );
 134         echo "  <cc:{$type} rdf:about=\"{$url}\">\n";
 135 }
 136
 137 /* private */ function ccSubEpilogue($type) {
 138         echo "  </cc:{$type}>\n";
 139 }
 140
 141 /* private */ function ccLicense($terms) {
 142
 143         foreach ($terms as $term) {
 144                 switch ($term) {
 145                 case 're':
 146                         ccTerm('permits', "Reproduction"); break;
 147                 case 'di':
 148                         ccTerm('permits', "Distribution"); break;
 149                 case 'de':
 150                         ccTerm('permits', "DerivativeWorks"); break;
 151                 case 'nc':
 152                         ccTerm('prohibits', "CommercialUse"); break;
 153                 case 'no':
 154                         ccTerm('requires', "Notice"); break;
 155                 case 'by':
 156                         ccTerm('requires', "Attribution"); break;
 157                 case 'sa':
 158                         ccTerm('requires', "ShareAlike"); break;
 159                 case 'sc':
 160                         ccTerm('requires', "SourceCode"); break;
 161                 }
 162         }
 163 }
 164
 165 /* private */ function ccTerm($term, $name) {
 166         print "    <cc:{$term} rdf:resource=\"http://web.resource.org/cc/{$name}\" />\n";
 167 }
 168
 169 /* private */ function ccEpilogue() {
 170         echo "</rdf:RDF>\n";
 171 }
 172
 173 /* private */ function dcElement($name, $value) {
 174         $value = htmlspecialchars( $value );
 175         print "    <dc:{$name}>{$value}</dc:{$name}>\n";
 176 }
 177
 178 /* private */ function dcDate($timestamp) {
 179         return substr($timestamp, 0, 4) . "-"
 180                 . substr($timestamp, 4, 2) . "-"
 181                 . substr($timestamp, 6, 2);
 182 }
 183
 184 /* private */ function dcReallyFullUrl($title) {
 185         return $title->getFullURL();
 186 }
 187
 188 /* private */ function dcPageOrString($name, $page, $str) {
 189         $nt = Title::newFromText($page);
 190
 191         if (!$nt || $nt->getArticleID() == 0) {
 192                 dcElement($name, $str);
 193         } else {
 194                 dcPage($name, $nt);
 195         }
 196 }
 197
 198 /* private */ function dcPage($name, $title) {
 199         dcUrl($name, dcReallyFullUrl($title));
 200 }
 201
 202 /* private */ function dcUrl($name, $url) {
 203         $url = htmlspecialchars( $url );
 204         print "    <dc:{$name} rdf:resource=\"{$url}\" />\n";
 205 }
 206
 207 /* private */ function dcPerson($name, $id) {
 208         global $wgLang;
 209
 210         if ($id == 0) {
 211                 dcElement($name, wfMsg("anonymous"));
 212         } else {
 213                 $user_name = User::whoIs($id);
 214                 dcPageOrString($name, $wgLang->getNsText(NS_USER) . ":" . $user_name, $user_name);
 215         }
 216 }
 217
 218 /* private */ function dcContributors($title) {
 219
 220         $contribs = array();
 221
 222         $res = wfQuery("SELECT DISTINCT old_user" .
 223                        " FROM old " .
 224                        " WHERE old_namespace = " . $title->getNamespace() .
 225                        " AND old_title = '" . $title->getDBkey() . "'", DB_READ);
 226
 227         while ( $line = wfFetchObject( $res ) ) {
 228                 $contribs[] = $line->old_user;
 229         }
 230
 231         return $contribs;
 232 }
 233
 234 /* Takes an arg, for future enhancement with different rights for
 235  different pages. */
 236
 237 /* private */ function dcRights($article) {
 238
 239         global $wgRightsPage, $wgRightsUrl, $wgRightsText;
 240
 241         if (isset($wgRightsPage) &&
 242                 ($nt = Title::newFromText($wgRightsPage))
 243                 && ($nt->getArticleID() != 0)) {
 244                 dcPage('rights', $nt);
 245         } else if (isset($wgRightsUrl)) {
 246                 dcUrl('rights', $wgRightsUrl);
 247         } else if (isset($wgRightsText)) {
 248                 dcElement('rights', $wgRightsText);
 249         }
 250 }
 251
 252 /* private */ function ccGetTerms($url) {
 253         global $wgLicenseTerms;
 254
 255         if (isset($wgLicenseTerms)) {
 256                 return $wgLicenseTerms;
 257         } else {
 258                 $known = getKnownLicenses();
 259                 return $known[$url];
 260         }
 261 }
 262
 263 /* private */ function getKnownLicenses() {
 264
 265         $ccLicenses = array('by', 'by-nd', 'by-nd-nc', 'by-nc',
 266                             'by-nc-sa', 'by-sa', 'nd', 'nd-nc',
 267                             'nc', 'nc-sa', 'sa');
 268
 269         $knownLicenses = array();
 270
 271         foreach ($ccLicenses as $license) {
 272                 $lurl = "http://creativecommons.org/licenses/{$license}/1.0/";
 273                 $knownLicenses[$lurl] = explode('-', $license);
 274                 $knownLicenses[$lurl][] = 're';
 275                 $knownLicenses[$lurl][] = 'di';
 276                 $knownLicenses[$lurl][] = 'no';
 277                 if (!in_array('nd', $knownLicenses[$lurl])) {
 278                         $knownLicenses[$lurl][] = 'de';
 279                 }
 280         }
 281
 282         /* Handle the GPL and LGPL, too. */
 283
 284         $knownLicenses["http://creativecommons.org/licenses/GPL/2.0/"] =
 285                 array('de', 're', 'di', 'no', 'sa', 'sc');
 286         $knownLicenses["http://creativecommons.org/licenses/LGPL/2.1/"] =
 287                 array('de', 're', 'di', 'no', 'sa', 'sc');
 288         $knownLicenses["http://www.gnu.org/copyleft/fdl.html"] =
 289                 array('de', 're', 'di', 'no', 'sa', 'sc');
 290
 291         return $knownLicenses;
 292 }
 293
 294 ?>