lib/RssWriter.php

   1 <?php // $Id$
   2 /*
   3  * Code for creating RSS 1.0.
   4  */
   5
   6 // Encoding for RSS output.
   7 if (!defined('RSS_ENCODING'))
   8   define('RSS_ENCODING', $GLOBALS['charset']);
   9
  10 /**
  11  * A class for writing RSS 1.0.
  12  *
  13  * @see http://purl.org/rss/1.0/spec,
  14  *      http://www.usemod.com/cgi-bin/mb.pl?ModWiki
  15  */
  16 class RssWriter extends XmlElement
  17 {
  18     function RssWriter () {
  19         $this->XmlElement('rdf:RDF',
  20                           array('xmlns' => "http://purl.org/rss/1.0/",
  21                                 'xmlns:rdf' => 'http://www.w3.org/1999/02/22-rdf-syntax-ns#'));
  22
  23     $this->_modules = array(
  24             //Standards
  25         'content'    => "http://purl.org/rss/1.0/modules/content/",
  26         'dc'    => "http://purl.org/dc/elements/1.1/",
  27         'sy'    => "http://purl.org/rss/1.0/modules/syndication/",
  28             //Proposed
  29             'wiki'      => "http://purl.org/rss/1.0/modules/wiki/",
  30         'ag'    => "http://purl.org/rss/1.0/modules/aggregation/",
  31         'annotate'    => "http://purl.org/rss/1.0/modules/annotate/",
  32         'audio'    => "http://media.tangent.org/rss/1.0/",
  33         'cp'    => "http://my.theinfo.org/changed/1.0/rss/",
  34         'rss091'    => "http://purl.org/rss/1.0/modules/rss091/",
  35         'slash'    => "http://purl.org/rss/1.0/modules/slash/",
  36         'taxo'    => "http://purl.org/rss/1.0/modules/taxonomy/",
  37         'thr'    => "http://purl.org/rss/1.0/modules/threading/"
  38         );
  39
  40     $this->_uris_seen = array();
  41         $this->_items = array();
  42     }
  43
  44     function registerModule($alias, $uri) {
  45     assert(!isset($this->_modules[$alias]));
  46     $this->_modules[$alias] = $uri;
  47     }
  48
  49     // Args should include:
  50     //  'title', 'link', 'description'
  51     // and can include:
  52     //  'URI'
  53     function channel($properties, $uri = false) {
  54         $this->_channel = $this->__node('channel', $properties, $uri);
  55     }
  56
  57     // Args should include:
  58     //  'title', 'link'
  59     // and can include:
  60     //  'description', 'URI'
  61     function addItem($properties, $uri = false) {
  62         $this->_items[] = $this->__node('item', $properties, $uri);
  63     }
  64
  65     // Args should include:
  66     //  'url', 'title', 'link'
  67     // and can include:
  68     //  'URI'
  69     function image($properties, $uri = false) {
  70         $this->_image = $this->__node('image', $properties, $uri);
  71     }
  72
  73     // Args should include:
  74     //  'title', 'description', 'name', and 'link'
  75     // and can include:
  76     //  'URI'
  77     function textinput($properties, $uri = false) {
  78         $this->_textinput = $this->__node('textinput', $properties, $uri);
  79     }
  80
  81     /**
  82      * Finish construction of RSS.
  83      */
  84     function finish() {
  85         if (isset($this->_finished))
  86             return;
  87
  88         $channel = &$this->_channel;
  89         $items = &$this->_items;
  90
  91         $seq = new XmlElement('rdf:Seq');
  92         if ($items) {
  93             foreach ($items as $item)
  94                 $seq->pushContent($this->__ref('rdf:li', $item));
  95         }
  96         $channel->pushContent(new XmlElement('items', false, $seq));
  97
  98     if (isset($this->_image)) {
  99             $channel->pushContent($this->__ref('image', $this->_image));
 100         $items[] = $this->_image;
 101     }
 102     if (isset($this->_textinput)) {
 103             $channel->pushContent($this->__ref('textinput', $this->_textinput));
 104         $items[] = $this->_textinput;
 105     }
 106
 107     $this->pushContent($channel);
 108     if ($items)
 109         $this->pushContent($items);
 110
 111         $this->__spew();
 112         $this->_finished = true;
 113     }
 114
 115     /**
 116      * Write output to HTTP client.
 117      */
 118     function __spew() {
 119         header("Content-Type: application/xml; charset=" . RSS_ENCODING);
 120         echo('<'.'?xml version="1.0" encoding="'.RSS_ENCODING.'"?'.">\n");
 121         //printf("<!-- generator=\"PhpWiki-%s\" -->\n", PHPWIKI_VERSION);
 122         $this->printXML();
 123     }
 124
 125
 126     /**
 127      * Create a new RDF <em>typedNode</em>.
 128      */
 129     function __node($type, $properties, $uri = false) {
 130     if (! $uri)
 131         $uri = $properties['link'];
 132     $attr['rdf:about'] = $this->__uniquify_uri($uri);
 133     return new XmlElement($type, $attr,
 134                               $this->__elementize($properties));
 135     }
 136
 137     /**
 138      * Check object URI for uniqueness, create a unique URI if needed.
 139      */
 140     function __uniquify_uri ($uri) {
 141     if (!$uri || isset($this->_uris_seen[$uri])) {
 142         $n = count($this->_uris_seen);
 143         $uri = $this->_channel->getAttr('rdf:about') . "#uri$n";
 144         assert(!isset($this->_uris_seen[$uri]));
 145     }
 146     $this->_uris_seen[$uri] = true;
 147     return $uri;
 148     }
 149
 150     /**
 151      * Convert hash of RDF properties to <em>propertyElt</em>s.
 152      */
 153     function __elementize ($elements) {
 154     $out = array();
 155         foreach ($elements as $prop => $val) {
 156         $this->__check_predicate($prop);
 157         if (is_array($val))
 158             $out[] = new XmlElement($prop, $val);
 159         elseif (is_object($val))
 160             $out[] = $val;
 161         else
 162             $out[] = new XmlElement($prop, false, $val);
 163     }
 164     return $out;
 165     }
 166
 167     /**
 168      * Check property predicates for XMLNS sanity.
 169      */
 170     function __check_predicate ($name) {
 171     if (preg_match('/^([^:]+):[^:]/', $name, $m)) {
 172         $ns = $m[1];
 173         if (! $this->getAttr("xmlns:$ns")) {
 174         if (!isset($this->_modules[$ns]))
 175             die("$name: unknown namespace ($ns)");
 176         $this->setAttr("xmlns:$ns", $this->_modules[$ns]);
 177         }
 178     }
 179     }
 180
 181     /**
 182      * Create a <em>propertyElt</em> which references another node in the RSS.
 183      */
 184     function __ref($predicate, $reference) {
 185         $attr['rdf:resource'] = $reference->getAttr('rdf:about');
 186         return new XmlElement($predicate, $attr);
 187     }
 188 };
 189
 190 /* Taken from mediawiki.
 191  * See http://www.atomenabled.org/developers/syndication/
 192  */
 193 class AtomFeed extends RssWriter {
 194
 195     // Args should include:
 196     //  'title', 'link', 'description'
 197     // and can include:
 198     //  'URI'
 199     function feed($properties, $uri = false) {
 200         global $LANG;
 201         $attr = array('xmlns' => 'http://www.w3.org/2005/Atom',
 202                   'version' => '0.3', // or 1.0
 203                   'lang' => $LANG);
 204         $this->_channel = $this->__node('feed', $attr, $properties, $uri);
 205     }
 206
 207     /**
 208      * Write output to HTTP client.
 209      */
 210     function __spew() {
 211         header("Content-Type: application/atom+xml; charset=" . RSS_ENCODING);
 212         echo('<'.'?xml version="1.0" encoding="'.RSS_ENCODING.'"?'.">\n");
 213         //printf("<!-- generator=\"PhpWiki-%s\" -->\n", PHPWIKI_VERSION);
 214         $this->printXML();
 215     }
 216
 217     /**
 218      * Create a new entry
 219      */
 220     function __node($type, $attr, $properties, $uri = false) {
 221     if (! $uri)
 222         $uri = $properties['link'];
 223     //$attr['rdf:about'] = $this->__uniquify_uri($uri);
 224     return new XmlElement($type, $attr,
 225                               $this->__elementize($properties));
 226     }
 227
 228     // Args should include:
 229     //  'title', 'link', author, modified, issued, created, summary,
 230     // and can include:
 231     //  comment
 232     function addItem($properties, $attr=false, $uri = false) {
 233         $this->_items[] = $this->__node('entry', $attr, $properties, $uri);
 234     }
 235
 236     /**
 237      * Print it.
 238      */
 239     function finish() {
 240         if (isset($this->_finished))
 241             return;
 242
 243         $channel = &$this->_channel;
 244         $items = &$this->_items;
 245     if ($items)
 246         $channel->pushContent($items);
 247     $this->pushContent($channel);
 248
 249         $this->__spew();
 250         $this->_finished = true;
 251     }
 252 }
 253
 254 // Local Variables:
 255 // mode: php
 256 // tab-width: 8
 257 // c-basic-offset: 4
 258 // c-hanging-comment-ender-p: nil
 259 // indent-tabs-mode: nil
 260 // End:
 261 ?>