feedwordpress / feedtime.class.php

feedtime.class.php in FeedWordPress trunk, at feedtime.class.php

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1	<?php
2	/**
3	* class FeedTime: handle common date-time formats used in feeds.
4	* We will try to be as tolerant as possible of different representations, since
5	* RSS Is A Fucking Mess, broken dates seem to be especially pervasive, etc.
6	* Supports anything that your version of PHP's strtotime() can handle; also has
7	* a built-in parser for W3C DTF, in case your PHP doesn't have that.
8	*
9	* Tries to parse a W3C DTF first; then falls back to strtotime(). If strtotime
10	* fails due to a mystery timezone, then we will try again on local time, with
11	* the timezone stripped out.
12	*
13	* To parse a string representation of a date-time from a feed, instantiate and
14	* then pull the timestamp:
15	*
16	* $time = new FeedTime($s);
17	* if ( ! $time->failed()) :
18	* $ts = $time->timestamp();
19	* else :
20	* // ...
21	* endif;
22	*/
23	class FeedTime {
24	var $rep;
25	var $ts;
26
27	function __construct( $time ) {
28	$this->set($time);
29	} /* FeedTime constructor */
30
31	function FeedTime( $time ) {
32	self::__construct( $time );
33	}
34
35	function set ($time, $recurse = false) {
36	$this->rep = $time;
37	$this->ts = NULL;
38	if (is_numeric($time)) : // Presumably a Unix-epoch timestamp
39	$this->ts = $this->rep;
40	elseif (is_string($time)) :
41	// First, try to parse it as a W3C date-time
42	$this->ts = $this->parse_w3cdtf();
43
44	if ($this->failed()) :
45	// In some versions of PHP, strtotime() does not
46	// support the UT timezone. But since UT is by
47	// definition within 1 second of UTC, we'll just
48	// convert it preemptively to avoid problems.
49	$time = preg_replace(
50	'/(\s)UT$/',
51	'$1UTC',
52	$time
53	);
54	$this->ts = strtotime($time);
55
56	if ($this->failed()
57	and preg_match('/^(.*)([+\-][0-9]+\|\s+[A-Za-z]{1,3})$/', $time, $matches)) :
58	// Try dropping the time zone and recurse
59	$this->set($matches[1], /recurse=/ true);
60	endif;
61	endif;
62	endif;
63	} /* FeedTime::set() */
64
65	function timestamp () {
66	$unix = NULL;
67	if ( ! $this->failed()) :
68	$unix = $this->ts;
69	endif;
70	return $unix;
71	} /* FeedTime::timestamp() */
72
73	function failed () {
74	return ( !is_numeric($this->ts) or ! $this->ts or ($this->ts <= 0));
75	} /* FeedTime::failed() */
76
77	/**
78	* FeedTime::parse_w3cdtf() parses a W3C date-time format date into a
79	* Unix epoch timestamp. Derived from the parse_w3cdtf function included
80	* with MagpieRSS by Kellan Elliot-McCrea <kellan@protest.net>, with
81	* modifications and bugfixes by Charles Johnson
82	* <technophilia@radgeek.com>, under the terms of the GPL.
83	*/
84	function parse_w3cdtf () {
85	$unix = NULL; // Failure
86
87	# regex to match wc3dtf
88	$pat = "/^\s*
89	(\d{4})
90	(-
91	(\d{2})
92	(-
93	(\d{2})
94	(T
95	(\d{2})
96	:(\d{2})
97	(:
98	(\d{2})
99	(\.\d+)?
100	)?
101	(?:([-+])(\d{2}):?(\d{2})\|(Z))?
102	)?
103	)?
104	)?
105	\s*\$
106	/x";
107
108	if ( preg_match( $pat, $this->rep, $match ) ) :
109	$year = (isset($match[1]) ? $match[1] : NULL);
110	$month = (isset($match[3]) ? $match[3] : NULL);
111	$day = (isset($match[5]) ? $match[5] : NULL);
112	$hours = (isset($match[7]) ? $match[7] : NULL);
113	$minutes = (isset($match[8]) ? $match[8] : NULL);
114	$seconds = (isset($match[10]) ? $match[10] : NULL);
115
116	# W3C dates can omit the time, the day of the month, or even the month.
117	# Fill in any blanks using information from the present moment. --CWJ
118	$default['hr'] = (int) gmdate('H');
119	$default['day'] = (int) gmdate('d');
120	$default['month'] = (int) gmdate('m');
121
122	if (is_null($hours)) : $hours = $default['hr']; $minutes = 0; $seconds = 0; endif;
123	if (is_null($day)) : $day = $default['day']; endif;
124	if (is_null($month)) : $month = $default['month']; endif;
125
126	# calc epoch for current date assuming GMT
127	$unix = gmmktime( $hours, $minutes, $seconds, $month, $day, $year);
128
129	$offset = 0;
130	if ( isset($match[15]) and $match[15] == 'Z' ) :
131	# zulu time, aka GMT
132	else :
133	$tz_mod = (isset($match[12]) ? $match[12] : NULL);
134	$tz_hour = (isset($match[13]) ? $match[13] : NULL);
135	$tz_min = (isset($match[14]) ? $match[14] : NULL);
136
137	# zero out the variables
138	if ( is_null($tz_hour) ) :
139	$offset = (int) get_option('gmt_offset');
140	$tz_hour = abs($offset);
141	$tz_mod = ((abs($offset) != $offset) ? '-' : '+');
142	endif;
143	if ( is_null($tz_min) ) : $tz_min = 0; endif;
144
145	$offset_secs = (($tz_hour60)+$tz_min)60;
146
147	# is timezone ahead of GMT? then subtract offset
148	if ( $tz_mod == '+' ) :
149	$offset_secs = $offset_secs * -1;
150	endif;
151	$offset = $offset_secs;
152	endif;
153	$unix = $unix + $offset;
154	endif;
155	return $unix;
156	} /* FeedTime::parse_w3cdtf () */
157	} /* class FeedTime */
158