1 <?php rcs_id('$Id: RssWriter.php,v 1.8 2004-04-18 01:11:51 rurban Exp $');
3 * Code for creating RSS 1.0.
7 // Encoding for RSS output.
8 define('RSS_ENCODING', $GLOBALS['charset']);
11 * A class for writing RSS 1.0.
13 * @see http://purl.org/rss/1.0/spec,
14 * http://www.usemod.com/cgi-bin/mb.pl?ModWiki
16 class RssWriter extends XmlElement
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#'));
23 $this->_modules = array(
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/",
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/"
40 $this->_uris_seen = array();
41 $this->_items = array();
44 function registerModule($alias, $uri) {
45 assert(!isset($this->_modules[$alias]));
46 $this->_modules[$alias] = $uri;
49 // Args should include:
50 // 'title', 'link', 'description'
53 function channel($properties, $uri = false) {
54 $this->_channel = $this->__node('channel', $properties, $uri);
57 // Args should include:
60 // 'description', 'URI'
61 function addItem($properties, $uri = false) {
62 $this->_items[] = $this->__node('item', $properties, $uri);
65 // Args should include:
66 // 'url', 'title', 'link'
69 function image($properties, $uri = false) {
70 $this->_image = $this->__node('image', $properties, $uri);
73 // Args should include:
74 // 'title', 'description', 'name', and 'link'
77 function textinput($properties, $uri = false) {
78 $this->_textinput = $this->__node('textinput', $properties, $uri);
82 * Finish construction of RSS.
85 if (isset($this->_finished))
88 $channel = &$this->_channel;
89 $items = &$this->_items;
91 $seq = new XmlElement('rdf:Seq');
93 foreach ($items as $item)
94 $seq->pushContent($this->__ref('rdf:li', $item));
96 $channel->pushContent(new XmlElement('items', false, $seq));
98 if (isset($this->_image)) {
99 $channel->pushContent($this->__ref('image', $this->_image));
100 $items[] = $this->_image;
102 if (isset($this->_textinput)) {
103 $channel->pushContent($this->__ref('textinput', $this->_textinput));
104 $items[] = $this->_textinput;
107 $this->pushContent($channel);
109 $this->pushContent($items);
112 $this->_finished = true;
117 * Write output to HTTP client.
120 header("Content-Type: application/xml; charset=" . RSS_ENCODING);
121 printf("<?xml version=\"1.0\" encoding=\"%s\"?>\n", RSS_ENCODING);
127 * Create a new RDF <em>typedNode</em>.
129 function __node($type, $properties, $uri = false) {
131 $uri = $properties['link'];
132 $attr['rdf:about'] = $this->__uniquify_uri($uri);
133 return new XmlElement($type, $attr,
134 $this->__elementize($properties));
138 * Check object URI for uniqueness, create a unique URI if needed.
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]));
146 $this->_uris_seen[$uri] = true;
151 * Convert hash of RDF properties to <em>propertyElt</em>s.
153 function __elementize ($elements) {
155 foreach ($elements as $prop => $val) {
156 $this->__check_predicate($prop);
157 $out[] = new XmlElement($prop, false, $val);
163 * Check property predicates for XMLNS sanity.
165 function __check_predicate ($name) {
166 if (preg_match('/^([^:]+):[^:]/', $name, $m)) {
168 if (! $this->getAttr("xmlns:$ns")) {
169 if (!isset($this->_modules[$ns]))
170 die("$name: unknown namespace ($ns)");
171 $this->setAttr("xmlns:$ns", $this->_modules[$ns]);
177 * Create a <em>propertyElt</em> which references another node in the RSS.
179 function __ref($predicate, $reference) {
180 $attr['rdf:resource'] = $reference->getAttr('rdf:about');
181 return new XmlElement($predicate, $attr);
186 // (c-file-style: "gnu")
191 // c-hanging-comment-ender-p: nil
192 // indent-tabs-mode: nil