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($wgRightsUrl)) {
  44           print "    <cc:license rdf:resource=\"$wgRightsUrl\" />\n";
  45       }
  46
  47       ccSubEpilogue('Work');
  48
  49       if (isset($wgRightsUrl)) {
  50           $terms = ccGetTerms($wgRightsUrl);
  51           if ($terms) {
  52               ccSubPrologue('License', $wgRightsUrl);
  53       ccLicense($terms);
  54               ccSubEpilogue('License');
  55           }
  56       }
  57   }
  58
  59   ccEpilogue();
  60 }
  61
  62 /* private */ function rdfSetup() {
  63   global $wgOut, $wgRdfMimeType, $_SERVER;
  64
  65   $rdftype = wfNegotiateType(wfAcceptToPrefs($_SERVER['HTTP_ACCEPT']), wfAcceptToPrefs(RDF_TYPE_PREFS));
  66
  67   if (!$rdftype) {
  68       wfHttpError(406, "Not Acceptable", wfMsg("notacceptable"));
  69       return false;
  70   } else {
  71       $wgOut->disable();
  72       header( "Content-type: {$rdftype}" );
  73       $wgOut->sendCacheControl();
  74       return true;
  75   }
  76 }
  77
  78 /* private */ function dcPrologue($url) {
  79   global $wgOutputEncoding;
  80
  81   print "<?xml version=\"1.0\" encoding=\"{$wgOutputEncoding}\" ?>
  82
  83 <!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\">
  84
  85 <rdf:RDF xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\"
  86          xmlns:dc=\"http://purl.org/dc/elements/1.1/\">
  87   <rdf:Description rdf:about=\"$url\">
  88 ";
  89 }
  90
  91 /* private */ function dcEpilogue() {
  92     print "
  93   </rdf:Description>
  94 </rdf:RDF>
  95 ";
  96 }
  97
  98 /* private */ function dcBasics($article) {
  99   global $wgLanguageCode, $wgSitename;
 100
 101   dcElement('title', $article->mTitle->getText());
 102   dcPageOrString('publisher', wfMsg('aboutpage'), $wgSitename);
 103   dcElement('language', $wgLanguageCode);
 104   dcElement('type', 'Text');
 105   dcElement('format', 'text/html');
 106   dcElement('identifier', dcReallyFullUrl($article->mTitle));
 107   dcElement('date', dcDate($article->getTimestamp()));
 108   dcPerson('creator', $article->getUser());
 109
 110   $contributors = dcContributors($article->mTitle);
 111
 112   foreach ($contributors as $cid) {
 113     dcPerson('contributor', $cid);
 114   }
 115
 116   dcRights($article);
 117 }
 118
 119 /* private */ function ccPrologue() {
 120     global $wgOutputEncoding;
 121
 122     echo "<?xml version='1.0'  encoding='{$wgOutputEncoding}' ?>
 123
 124 <rdf:RDF xmlns:cc=\"http://web.resource.org/cc/\"
 125          xmlns:dc=\"http://purl.org/dc/elements/1.1/\"
 126          xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\">
 127 ";
 128 }
 129
 130 /* private */ function ccSubPrologue($type, $url) {
 131     echo "  <cc:{$type} rdf:about=\"{$url}\">\n";
 132 }
 133
 134 /* private */ function ccSubEpilogue($type) {
 135     echo "  </cc:{$type}>\n";
 136 }
 137
 138 /* private */ function ccLicense($terms) {
 139
 140   foreach ($terms as $term) {
 141     switch ($term) {
 142     case 're':
 143       ccTerm('permits', "Reproduction"); break;
 144     case 'di':
 145       ccTerm('permits', "Distribution"); break;
 146     case 'de':
 147       ccTerm('permits', "DerivativeWorks"); break;
 148     case 'nc':
 149       ccTerm('prohibits', "CommercialUse"); break;
 150     case 'no':
 151       ccTerm('requires', "Notice"); break;
 152     case 'by':
 153       ccTerm('requires', "Attribution"); break;
 154     case 'sa':
 155       ccTerm('requires', "ShareAlike"); break;
 156     case 'sc':
 157       ccTerm('requires', "SourceCode"); break;
 158     }
 159   }
 160 }
 161
 162 /* private */ function ccTerm($term, $name) {
 163   print "    <cc:{$term} rdf:resource=\"http://web.resource.org/cc/{$name}\" />\n";
 164 }
 165
 166 /* private */ function ccEpilogue() {
 167     echo "</rdf:RDF>\n";
 168 }
 169
 170 /* private */ function dcElement($name, $value) {
 171   print "    <dc:{$name}>{$value}</dc:{$name}>\n";
 172 }
 173
 174 /* private */ function dcDate($timestamp) {
 175   return substr($timestamp, 0, 4) . "-"
 176     . substr($timestamp, 4, 2) . "-"
 177     . substr($timestamp, 6, 2);
 178 }
 179
 180 /* private */ function dcReallyFullUrl($title) {
 181   $title->getFullURL();
 182 }
 183
 184 /* private */ function dcPageOrString($name, $page, $str) {
 185   $nt = Title::newFromText($page);
 186
 187   if (!$nt || $nt->getArticleID() == 0) {
 188     dcElement($name, $str);
 189   } else {
 190     dcPage($name, $nt);
 191   }
 192 }
 193
 194 /* private */ function dcPage($name, $title) {
 195   dcUrl($name, dcReallyFullUrl($title));
 196 }
 197
 198 /* private */ function dcUrl($name, $url) {
 199   print "    <dc:{$name} rdf:resource=\"{$url}\" />\n";
 200 }
 201
 202 /* private */ function dcPerson($name, $id) {
 203   global $wgLang;
 204
 205   if ($id == 0) {
 206     dcElement($name, wfMsg("anonymous"));
 207   } else {
 208     $user_name = User::whoIs($id);
 209     dcPageOrString($name, $wgLang->getNsText(NS_USER) . ":" . $user_name, $user_name);
 210   }
 211 }
 212
 213 /* private */ function dcContributors($title) {
 214
 215   $contribs = array();
 216
 217   $res = wfQuery("SELECT DISTINCT old_user" .
 218                  " FROM old " .
 219                  " WHERE old_namespace = " . $title->getNamespace() .
 220                  " AND old_title = '" . $title->getDBkey() . "'", DB_READ);
 221
 222   while ( $line = wfFetchObject( $res ) ) {
 223     $contribs[] = $line->old_user;
 224   }
 225
 226   return $contribs;
 227 }
 228
 229 /* Takes an arg, for future enhancement with different rights for
 230  different pages. */
 231
 232 /* private */ function dcRights($article) {
 233
 234   global $wgRightsPage, $wgRightsUrl, $wgRightsText;
 235
 236   if (isset($wgRightsPage) &&
 237       ($nt = Title::newFromText($wgRightsPage))
 238       && ($nt->getArticleID() != 0)) {
 239       dcPage('rights', $nt);
 240   } else if (isset($wgRightsUrl)) {
 241     dcUrl('rights', $wgRightsUrl);
 242   } else if (isset($wgRightsText)) {
 243     dcElement('rights', $wgRightsText);
 244   }
 245 }
 246
 247 /* private */ function ccGetTerms($url) {
 248   global $wgLicenseTerms;
 249
 250   if (isset($wgLicenseTerms)) {
 251     return $wgLicenseTerms;
 252   } else {
 253     $known = getKnownLicenses();
 254     return $known[$url];
 255   }
 256 }
 257
 258 /* private */ function getKnownLicenses() {
 259
 260   $ccLicenses = array('by', 'by-nd', 'by-nd-nc', 'by-nc',
 261                       'by-nc-sa', 'by-sa', 'nd', 'nd-nc',
 262                       'nc', 'nc-sa', 'sa');
 263
 264   $knownLicenses = array();
 265
 266   foreach ($ccLicenses as $license) {
 267     $lurl = "http://creativecommons.org/licenses/{$license}/1.0/";
 268     $knownLicenses[$lurl] = explode('-', $license);
 269     $knownLicenses[$lurl][] = 're';
 270     $knownLicenses[$lurl][] = 'di';
 271     $knownLicenses[$lurl][] = 'no';
 272     if (!in_array('nd', $knownLicenses[$lurl])) {
 273       $knownLicenses[$lurl][] = 'de';
 274     }
 275   }
 276
 277   /* Handle the GPL and LGPL, too. */
 278
 279   $knownLicenses["http://creativecommons.org/licenses/GPL/2.0/"] =
 280     array('de', 're', 'di', 'no', 'sa', 'sc');
 281   $knownLicenses["http://creativecommons.org/licenses/LGPL/2.1/"] =
 282     array('de', 're', 'di', 'no', 'sa', 'sc');
 283   $knownLicenses["http://www.gnu.org/copyleft/fdl.html"] =
 284     array('de', 're', 'di', 'no', 'sa', 'sc');
 285
 286   return $knownLicenses;
 287 }
 288
 289 ?>