lib/RssWriter.php

   1 <?php
   2 /*
   3  * Code for creating RSS 1.0.
   4  */
   5
   6 /**
   7  * A class for writing RSS 1.0.
   8  *
   9  * @see http://purl.org/rss/1.0/spec,
  10  *      http://www.usemod.com/cgi-bin/mb.pl?ModWiki
  11  */
  12 class RssWriter extends XmlElement
  13 {
  14     function __construct()
  15     {
  16         $this->XmlElement('rdf:RDF',
  17             array('xmlns' => "http://purl.org/rss/1.0/",
  18                 'xmlns:rdf' => 'http://www.w3.org/1999/02/22-rdf-syntax-ns#'));
  19
  20         $this->_modules = array(
  21             //Standards
  22             'content' => "http://purl.org/rss/1.0/modules/content/",
  23             'dc' => "http://purl.org/dc/elements/1.1/",
  24             'sy' => "http://purl.org/rss/1.0/modules/syndication/",
  25             //Proposed
  26             'wiki' => "http://purl.org/rss/1.0/modules/wiki/",
  27             'ag' => "http://purl.org/rss/1.0/modules/aggregation/",
  28             'annotate' => "http://purl.org/rss/1.0/modules/annotate/",
  29             'audio' => "http://media.tangent.org/rss/1.0/",
  30             'cp' => "http://my.theinfo.org/changed/1.0/rss/",
  31             'rss091' => "http://purl.org/rss/1.0/modules/rss091/",
  32             'slash' => "http://purl.org/rss/1.0/modules/slash/",
  33             'taxo' => "http://purl.org/rss/1.0/modules/taxonomy/",
  34             'thr' => "http://purl.org/rss/1.0/modules/threading/"
  35         );
  36
  37         $this->_uris_seen = array();
  38         $this->_items = array();
  39     }
  40
  41     function registerModule($alias, $uri)
  42     {
  43         assert(!isset($this->_modules[$alias]));
  44         $this->_modules[$alias] = $uri;
  45     }
  46
  47     // Args should include:
  48     //  'title', 'link', 'description'
  49     // and can include:
  50     //  'URI'
  51     function channel($properties, $uri = false)
  52     {
  53         $this->_channel = $this->__node('channel', $properties, $uri);
  54     }
  55
  56     // Args should include:
  57     //  'title', 'link'
  58     // and can include:
  59     //  'description', 'URI'
  60     function addItem($properties, $uri = false)
  61     {
  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     {
  71         $this->_image = $this->__node('image', $properties, $uri);
  72     }
  73
  74     // Args should include:
  75     //  'title', 'description', 'name', and 'link'
  76     // and can include:
  77     //  'URI'
  78     function textinput($properties, $uri = false)
  79     {
  80         $this->_textinput = $this->__node('textinput', $properties, $uri);
  81     }
  82
  83     /**
  84      * Finish construction of RSS.
  85      */
  86     function finish()
  87     {
  88         if (isset($this->_finished))
  89             return;
  90
  91         $channel = &$this->_channel;
  92         $items = &$this->_items;
  93
  94         $seq = new XmlElement('rdf:Seq');
  95         if ($items) {
  96             foreach ($items as $item)
  97                 $seq->pushContent($this->__ref('rdf:li', $item));
  98         }
  99         $channel->pushContent(new XmlElement('items', false, $seq));
 100
 101         if (isset($this->_image)) {
 102             $channel->pushContent($this->__ref('image', $this->_image));
 103             $items[] = $this->_image;
 104         }
 105         if (isset($this->_textinput)) {
 106             $channel->pushContent($this->__ref('textinput', $this->_textinput));
 107             $items[] = $this->_textinput;
 108         }
 109
 110         $this->pushContent($channel);
 111         if ($items)
 112             $this->pushContent($items);
 113
 114         $this->__spew();
 115         $this->_finished = true;
 116     }
 117
 118     /**
 119      * Write output to HTTP client.
 120      */
 121     function __spew()
 122     {
 123         header("Content-Type: application/xml; charset=" . RSS_ENCODING);
 124         echo('<' . '?xml version="1.0" encoding="' . RSS_ENCODING . '"?' . ">\n");
 125         $this->printXML();
 126     }
 127
 128     /**
 129      * Create a new RDF <em>typedNode</em>.
 130      */
 131     function __node($type, $properties, $uri = false)
 132     {
 133         if (!$uri)
 134             $uri = $properties['link'];
 135         $attr['rdf:about'] = $this->__uniquify_uri($uri);
 136         return new XmlElement($type, $attr,
 137             $this->__elementize($properties));
 138     }
 139
 140     /**
 141      * Check object URI for uniqueness, create a unique URI if needed.
 142      */
 143     function __uniquify_uri($uri)
 144     {
 145         if (!$uri || isset($this->_uris_seen[$uri])) {
 146             $n = count($this->_uris_seen);
 147             $uri = $this->_channel->getAttr('rdf:about') . "#uri$n";
 148             assert(!isset($this->_uris_seen[$uri]));
 149         }
 150         $this->_uris_seen[$uri] = true;
 151         return $uri;
 152     }
 153
 154     /**
 155      * Convert hash of RDF properties to <em>propertyElt</em>s.
 156      */
 157     function __elementize($elements)
 158     {
 159         $out = array();
 160         foreach ($elements as $prop => $val) {
 161             $this->__check_predicate($prop);
 162             if (is_array($val))
 163                 $out[] = new XmlElement($prop, $val);
 164             elseif (is_object($val))
 165                 $out[] = $val; else
 166                 $out[] = new XmlElement($prop, false, $val);
 167         }
 168         return $out;
 169     }
 170
 171     /**
 172      * Check property predicates for XMLNS sanity.
 173      */
 174     function __check_predicate($name)
 175     {
 176         if (preg_match('/^([^:]+):[^:]/', $name, $m)) {
 177             $ns = $m[1];
 178             if (!$this->getAttr("xmlns:$ns")) {
 179                 if (!isset($this->_modules[$ns]))
 180                     die("$name: unknown namespace ($ns)");
 181                 $this->setAttr("xmlns:$ns", $this->_modules[$ns]);
 182             }
 183         }
 184     }
 185
 186     /**
 187      * Create a <em>propertyElt</em> which references another node in the RSS.
 188      */
 189     function __ref($predicate, $reference)
 190     {
 191         $attr['rdf:resource'] = $reference->getAttr('rdf:about');
 192         return new XmlElement($predicate, $attr);
 193     }
 194 }
 195
 196 /* Taken from mediawiki.
 197  * See http://www.atomenabled.org/developers/syndication/
 198  */
 199 class AtomFeed extends RssWriter
 200 {
 201
 202     // Args should include:
 203     //  'title', 'link', 'description'
 204     // and can include:
 205     //  'URI'
 206     function feed($properties, $uri = false)
 207     {
 208         global $LANG;
 209         $attr = array('xmlns' => 'http://www.w3.org/2005/Atom',
 210             'version' => '0.3', // or 1.0
 211             'lang' => $LANG);
 212         $this->_channel = $this->__node('feed', $attr, $properties, $uri);
 213     }
 214
 215     /**
 216      * Write output to HTTP client.
 217      */
 218     function __spew()
 219     {
 220         header("Content-Type: application/atom+xml; charset=" . RSS_ENCODING);
 221         echo('<' . '?xml version="1.0" encoding="' . RSS_ENCODING . '"?' . ">\n");
 222         $this->printXML();
 223     }
 224
 225     /**
 226      * Create a new entry
 227      */
 228     function __node($type, $attr, $properties, $uri = false)
 229     {
 230         if (!$uri)
 231             $uri = $properties['link'];
 232         //$attr['rdf:about'] = $this->__uniquify_uri($uri);
 233         return new XmlElement($type, $attr,
 234             $this->__elementize($properties));
 235     }
 236
 237     // Args should include:
 238     //  'title', 'link', author, modified, issued, created, summary,
 239     // and can include:
 240     //  comment
 241     function addItem($properties, $attr = false, $uri = false)
 242     {
 243         $this->_items[] = $this->__node('entry', $attr, $properties, $uri);
 244     }
 245
 246     /**
 247      * Print it.
 248      */
 249     function finish()
 250     {
 251         if (isset($this->_finished))
 252             return;
 253
 254         $channel = &$this->_channel;
 255         $items = &$this->_items;
 256         if ($items)
 257             $channel->pushContent($items);
 258         $this->pushContent($channel);
 259
 260         $this->__spew();
 261         $this->_finished = true;
 262     }
 263 }
 264
 265 // Local Variables:
 266 // mode: php
 267 // tab-width: 8
 268 // c-basic-offset: 4
 269 // c-hanging-comment-ender-p: nil
 270 // indent-tabs-mode: nil
 271 // End: