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     public $_channel;
  15     public $_image;
  16     public $_textinput;
  17
  18     function __construct()
  19     {
  20         parent::__construct('rdf:RDF',
  21             array('xmlns' => "http://purl.org/rss/1.0/",
  22                 'xmlns:rdf' => 'http://www.w3.org/1999/02/22-rdf-syntax-ns#'));
  23
  24         $this->_modules = array(
  25             //Standards
  26             'content' => "http://purl.org/rss/1.0/modules/content/",
  27             'dc' => "http://purl.org/dc/elements/1.1/",
  28             'sy' => "http://purl.org/rss/1.0/modules/syndication/",
  29             //Proposed
  30             'wiki' => "http://purl.org/rss/1.0/modules/wiki/",
  31             'ag' => "http://purl.org/rss/1.0/modules/aggregation/",
  32             'annotate' => "http://purl.org/rss/1.0/modules/annotate/",
  33             'audio' => "http://media.tangent.org/rss/1.0/",
  34             'cp' => "http://my.theinfo.org/changed/1.0/rss/",
  35             'rss091' => "http://purl.org/rss/1.0/modules/rss091/",
  36             'slash' => "http://purl.org/rss/1.0/modules/slash/",
  37             'taxo' => "http://purl.org/rss/1.0/modules/taxonomy/",
  38             'thr' => "http://purl.org/rss/1.0/modules/threading/"
  39         );
  40
  41         $this->_uris_seen = array();
  42         $this->_items = array();
  43     }
  44
  45     function registerModule($alias, $uri)
  46     {
  47         assert(!isset($this->_modules[$alias]));
  48         $this->_modules[$alias] = $uri;
  49     }
  50
  51     // Args should include:
  52     //  'title', 'link', 'description'
  53     // and can include:
  54     //  'URI'
  55     function channel($properties, $uri = false)
  56     {
  57         $this->_channel = $this->__node('channel', $properties, $uri);
  58     }
  59
  60     // Args should include:
  61     //  'title', 'link'
  62     // and can include:
  63     //  'description', 'URI'
  64     function addItem($properties, $uri = false)
  65     {
  66         $this->_items[] = $this->__node('item', $properties, $uri);
  67     }
  68
  69     // Args should include:
  70     //  'url', 'title', 'link'
  71     // and can include:
  72     //  'URI'
  73     function image($properties, $uri = false)
  74     {
  75         $this->_image = $this->__node('image', $properties, $uri);
  76     }
  77
  78     // Args should include:
  79     //  'title', 'description', 'name', and 'link'
  80     // and can include:
  81     //  'URI'
  82     function textinput($properties, $uri = false)
  83     {
  84         $this->_textinput = $this->__node('textinput', $properties, $uri);
  85     }
  86
  87     /**
  88      * Finish construction of RSS.
  89      */
  90     function finish()
  91     {
  92         if (isset($this->_finished))
  93             return;
  94
  95         $channel = &$this->_channel;
  96         $items = &$this->_items;
  97
  98         $seq = new XmlElement('rdf:Seq');
  99         if ($items) {
 100             foreach ($items as $item)
 101                 $seq->pushContent($this->__ref('rdf:li', $item));
 102         }
 103         $channel->pushContent(new XmlElement('items', false, $seq));
 104
 105         if (isset($this->_image)) {
 106             $channel->pushContent($this->__ref('image', $this->_image));
 107             $items[] = $this->_image;
 108         }
 109         if (isset($this->_textinput)) {
 110             $channel->pushContent($this->__ref('textinput', $this->_textinput));
 111             $items[] = $this->_textinput;
 112         }
 113
 114         $this->pushContent($channel);
 115         if ($items)
 116             $this->pushContent($items);
 117
 118         $this->__spew();
 119         $this->_finished = true;
 120     }
 121
 122     /**
 123      * Write output to HTTP client.
 124      */
 125     function __spew()
 126     {
 127         header("Content-Type: application/xml; charset=UTF-8");
 128         echo('<' . '?xml version="1.0" encoding="UTF-8" ?' . ">\n");
 129         $this->printXML();
 130     }
 131
 132     /**
 133      * Create a new RDF <em>typedNode</em>.
 134      *
 135      * @param $type
 136      * @param $properties
 137      * @param bool $uri
 138      * @return XmlElement
 139      */
 140     function __node($type, $properties, $uri = false)
 141     {
 142         if (!$uri)
 143             $uri = $properties['link'];
 144         $attr['rdf:about'] = $this->__uniquify_uri($uri);
 145         return new XmlElement($type, $attr,
 146             $this->__elementize($properties));
 147     }
 148
 149     /**
 150      * Check object URI for uniqueness, create a unique URI if needed.
 151      *
 152      * @param string $uri
 153      * @return string
 154      */
 155     function __uniquify_uri($uri)
 156     {
 157         if (!$uri || isset($this->_uris_seen[$uri])) {
 158             $n = count($this->_uris_seen);
 159             $uri = $this->_channel->getAttr('rdf:about') . "#uri$n";
 160             assert(!isset($this->_uris_seen[$uri]));
 161         }
 162         $this->_uris_seen[$uri] = true;
 163         return $uri;
 164     }
 165
 166     /**
 167      * Convert hash of RDF properties to <em>propertyElt</em>s.
 168      *
 169      * @param $elements
 170      * @return array
 171      */
 172     function __elementize($elements)
 173     {
 174         $out = array();
 175         foreach ($elements as $prop => $val) {
 176             $this->__check_predicate($prop);
 177             if (is_array($val))
 178                 $out[] = new XmlElement($prop, $val);
 179             elseif (is_object($val))
 180                 $out[] = $val; else
 181                 $out[] = new XmlElement($prop, false, $val);
 182         }
 183         return $out;
 184     }
 185
 186     /**
 187      * Check property predicates for XMLNS sanity.
 188      *
 189      * @param string $name
 190      */
 191     function __check_predicate($name)
 192     {
 193         if (preg_match('/^([^:]+):[^:]/', $name, $m)) {
 194             $ns = $m[1];
 195             if (!$this->getAttr("xmlns:$ns")) {
 196                 if (!isset($this->_modules[$ns]))
 197                     die("$name: unknown namespace ($ns)");
 198                 $this->setAttr("xmlns:$ns", $this->_modules[$ns]);
 199             }
 200         }
 201     }
 202
 203     /**
 204      * Create a <em>propertyElt</em> which references another node in the RSS.
 205      *
 206      * @param $predicate
 207      * @param $reference
 208      * @return XmlElement
 209      */
 210     function __ref($predicate, $reference)
 211     {
 212         $attr['rdf:resource'] = $reference->getAttr('rdf:about');
 213         return new XmlElement($predicate, $attr);
 214     }
 215 }
 216
 217 /* Taken from mediawiki.
 218  * See http://www.atomenabled.org/developers/syndication/
 219  */
 220 class AtomFeed extends RssWriter
 221 {
 222
 223     // Args should include:
 224     //  'title', 'link', 'description'
 225     // and can include:
 226     //  'URI'
 227     function feed($properties, $uri = false)
 228     {
 229         global $LANG;
 230         $attr = array('xmlns' => 'http://www.w3.org/2005/Atom',
 231             'version' => '0.3', // or 1.0
 232             'lang' => $LANG);
 233         $this->_channel = $this->__node('feed', $attr, $properties, $uri);
 234     }
 235
 236     /**
 237      * Write output to HTTP client.
 238      */
 239     function __spew()
 240     {
 241         header("Content-Type: application/atom+xml; charset=UTF-8");
 242         echo('<' . '?xml version="1.0" encoding="UTF-8" ?' . ">\n");
 243         $this->printXML();
 244     }
 245
 246     /**
 247      * Create a new entry
 248      *
 249      * @param $type
 250      * @param $attr
 251      * @param bool $properties
 252      * @param bool $uri
 253      * @return XmlElement
 254      */
 255     function __node($type, $attr, $properties, $uri = false)
 256     {
 257         if (!$uri)
 258             $uri = $properties['link'];
 259         //$attr['rdf:about'] = $this->__uniquify_uri($uri);
 260         return new XmlElement($type, $attr,
 261             $this->__elementize($properties));
 262     }
 263
 264     // Args should include:
 265     //  'title', 'link', author, modified, issued, created, summary,
 266     // and can include:
 267     //  comment
 268     function addItem($properties, $attr = false, $uri = false)
 269     {
 270         $this->_items[] = $this->__node('entry', $attr, $properties, $uri);
 271     }
 272
 273     /**
 274      * Print it.
 275      */
 276     function finish()
 277     {
 278         if (isset($this->_finished))
 279             return;
 280
 281         $channel = &$this->_channel;
 282         $items = &$this->_items;
 283         if ($items)
 284             $channel->pushContent($items);
 285         $this->pushContent($channel);
 286
 287         $this->__spew();
 288         $this->_finished = true;
 289     }
 290 }
 291
 292 // Local Variables:
 293 // mode: php
 294 // tab-width: 8
 295 // c-basic-offset: 4
 296 // c-hanging-comment-ender-p: nil
 297 // indent-tabs-mode: nil
 298 // End: