feedwordpress / feedfinder.class.php

feedfinder.class.php in FeedWordPress 2009.1111, at feedfinder.class.php

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1	<?php
2	################################################################################
3	## class FeedFinder: find likely feeds using autodetection and/or guesswork ####
4	################################################################################
5
6	class FeedFinder {
7	var $uri = NULL;
8	var $_cache_uri = NULL;
9
10	var $verify = FALSE;
11
12	var $_response = NULL;
13	var $_data = NULL;
14	var $_error = NULL;
15	var $_head = NULL;
16
17	# -- Recognition patterns
18	var $_feed_types = array(
19	'application/rss+xml',
20	'text/xml',
21	'application/atom+xml',
22	'application/x.atom+xml',
23	'application/x-atom+xml'
24	);
25	var $_feed_markers = array('\\<feed', '\\<rss', 'xmlns="http://purl.org/rss/1.0');
26	var $_html_markers = array('\\<html');
27	var $_obvious_feed_url = array('[./]rss', '[./]rdf', '[./]atom', '[./]feed', '\.xml');
28	var $_maybe_feed_url = array ('rss', 'rdf', 'atom', 'feed', 'xml');
29
30	function FeedFinder ($uri = NULL, $verify = TRUE) {
31	$this->uri = $uri; $this->verify = $verify;
32	} /* FeedFinder::FeedFinder () */
33
34	function find ($uri = NULL) {
35	$ret = array ();
36	if (!is_null($this->data($uri))) {
37	if ($this->is_feed($uri)) {
38	$ret = array($this->uri);
39	} else {
40	// Assume that we have HTML or XHTML (even if we don't, who's it gonna hurt?)
41	// Autodiscovery is the preferred method
42	$href = $this->_link_rel_feeds();
43
44	// ... but we'll also take the little orange buttons
45	$href = array_merge($href, $this->_a_href_feeds(TRUE));
46
47	// If all that failed, look harder
48	if (count($href) == 0) $href = $this->_a_href_feeds(FALSE);
49
50	// Our search may turn up duplicate URIs. We only need to do any given URI once.
51	// Props to Camilo <http://projects.radgeek.com/2008/12/14/feedwordpress-20081214/#comment-20090122160414>
52	$href = array_unique($href);
53
54	// Verify feeds and resolve relative URIs
55	foreach ($href as $u) {
56	$the_uri = Relative_URI::resolve($u, $this->uri);
57	if ($this->verify) {
58	$feed =& new FeedFinder($the_uri);
59	if ($feed->is_feed()) $ret[] = $the_uri;
60	$feed = NULL;
61	} else {
62	$ret[] = $the_uri;
63	}
64	} /* foreach */
65	} /* if */
66	} /* if */
67	return array_unique($ret);
68	} /* FeedFinder::find () */
69
70	function data ($uri = NULL) {
71	$this->_get($uri);
72	return $this->_data;
73	}
74
75	function status ($uri = NULL) {
76	$this->_get($uri);
77
78	if (isset($this->_response->status)) :
79	$ret = $this->_response->status;
80	else :
81	$ret = NULL;
82	endif;
83	return $ret;
84	}
85
86	function error () {
87	return $this->_error;
88	}
89
90	function is_feed ($uri = NULL) {
91	$data = $this->data($uri);
92
93	return (
94	preg_match (
95	"\007(".implode('\|',$this->_feed_markers).")\007i",
96	$data
97	) and !preg_match (
98	"\007(".implode('\|',$this->_html_markers).")\007i",
99	$data
100	)
101	);
102	} /* FeedFinder::is_feed () */
103
104	# --- Private methods ---
105	function _get ($uri = NULL) {
106	if ($uri) $this->uri = $uri;
107
108	// Is the result not yet cached?
109	if ($this->_cache_uri !== $this->uri) :
110	$headers['Connection'] = 'close';
111	$headers['Accept'] = 'application/atom+xml application/rdf+xml application/rss+xml application/xml text/html /';
112	$headers['User-Agent'] = 'feedfinder/1.2 (compatible; PHP FeedFinder) +http://projects.radgeek.com/feedwordpress';
113
114	// Use function provided by MagpieRSS package
115	$client = _fetch_remote_file($this->uri, $headers);
116	if (isset($client->error)) :
117	$this->_error = $client->error;
118	else :
119	$this->_error = NULL;
120	endif;
121	$this->_response = $client;
122	$this->_data = $client->results;
123
124	// Kilroy was here
125	$this->_cache_uri = $this->uri;
126	endif;
127	} /* FeedFinder::_get () */
128
129	function _link_rel_feeds () {
130	$links = $this->_tags('link');
131	$link_count = count($links);
132
133	// now figure out which one points to the RSS file
134	$href = array ();
135	for ($n=0; $n<$link_count; $n++) {
136	if (strtolower($links[$n]['rel']) == 'alternate') {
137	if (in_array(strtolower($links[$n]['type']), $this->_feed_types)) {
138	$href[] = $links[$n]['href'];
139	} /* if */
140	} /* if */
141	} /* for */
142	return $href;
143	}
144
145	function _a_href_feeds ($obvious = TRUE) {
146	$pattern = ($obvious ? $this->_obvious_feed_url : $this->_maybe_feed_url);
147
148	$links = $this->_tags('a');
149	$link_count = count($links);
150
151	// now figure out which one points to the RSS file
152	$href = array ();
153	for ($n=0; $n<$link_count; $n++) {
154	if (preg_match("\007(".implode('\|',$pattern).")\007i", $links[$n]['href'])) {
155	$href[] = $links[$n]['href'];
156	} /* if */
157	} /* for */
158	return $href;
159	}
160
161	function _tags ($tag) {
162	$html = $this->data();
163
164	// search through the HTML, save all <link> tags
165	// and store each link's attributes in an associative array
166	preg_match_all('/<'.$tag.'\s+(.?)\s\/?>/si', $html, $matches);
167	$links = $matches[1];
168	$ret = array();
169	$link_count = count($links);
170	for ($n=0; $n<$link_count; $n++) {
171	$attributes = preg_split('/\s+/s', $links[$n]);
172	foreach($attributes as $attribute) {
173	$att = preg_split('/\s=\s/s', $attribute, 2);
174	if (isset($att[1])) {
175	$att[1] = preg_replace('/([\'"]?)(.*)\1/', '$2', $att[1]);
176	$final_link[strtolower($att[0])] = $att[1];
177	} /* if */
178	} /* foreach */
179	$ret[$n] = $final_link;
180	} /* for */
181	return $ret;
182	}
183	} /* class FeedFinder */
184
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