summaryrefslogtreecommitdiffstats
path: root/user_guide_src/source/helpers/date_helper.rst
blob: 18216c5a220d8876a137ae86f097716bb8370c50 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
###########
Date Helper
###########

The Date Helper file contains functions that help you work with dates.

.. contents:: Page Contents

Loading this Helper
===================

This helper is loaded using the following code

::

	$this->load->helper('date');

The following functions are available:

now()
=====

Returns the current time as a Unix timestamp, referenced either to your
server's local time or GMT, based on the "time reference" setting in
your config file. If you do not intend to set your master time reference
to GMT (which you'll typically do if you run a site that lets each user
set their own timezone settings) there is no benefit to using this
function over PHP's time() function.

.. php:method:: now()

mdate()
=======

This function is identical to PHPs `date() <http://www.php.net/date>`_
function, except that it lets you use MySQL style date codes, where each
code letter is preceded with a percent sign: %Y %m %d etc.

The benefit of doing dates this way is that you don't have to worry
about escaping any characters that are not date codes, as you would
normally have to do with the date() function. Example

.. php:method:: mdate($datestr = '', $time = '')

	:param string 	$datestr: Date String
	:param integer 	$time: time
	:returns: integer


::

	$datestring = "Year: %Y Month: %m Day: %d - %h:%i %a";
	$time = time();
	echo mdate($datestring, $time);

If a timestamp is not included in the second parameter the current time
will be used.

standard_date()
===============

Lets you generate a date string in one of several standardized formats.
Example

.. php:method:: standard_date($fmt = 'DATE_RFC822', $time = '')

	:param string 	$fmt: the chosen format
	:param string 	$time: Unix timestamp
	:returns: string

::

	$format = 'DATE_RFC822';
	$time = time();
	echo standard_date($format, $time);

The first parameter must contain the format, the second parameter must
contain the date as a Unix timestamp.

Supported formats:

+----------------+------------------------+-----------------------------------+
| Constant       | Description            | Example                           |
+================+========================+===================================+
| DATE_ATOM      | Atom                   | 2005-08-15T16:13:03+0000          |
+----------------+------------------------+-----------------------------------+
| DATE_COOKIE    | HTTP Cookies           | Sun, 14 Aug 2005 16:13:03 UTC     |
+----------------+------------------------+-----------------------------------+
| DATE_ISO8601   | ISO-8601               | 2005-08-14T16:13:03+00:00         |
+----------------+------------------------+-----------------------------------+
| DATE_RFC822    | RFC 822                | Sun, 14 Aug 05 16:13:03 UTC       |
+----------------+------------------------+-----------------------------------+
| DATE_RFC850    | RFC 850                | Sunday, 14-Aug-05 16:13:03 UTC    |
+----------------+------------------------+-----------------------------------+
| DATE_RFC1036   | RFC 1036               | Sunday, 14-Aug-05 16:13:03 UTC    |
+----------------+------------------------+-----------------------------------+
| DATE_RFC1123   | RFC 1123               | Sun, 14 Aug 2005 16:13:03 UTC     |
+----------------+------------------------+-----------------------------------+
| DATE_RFC2822   | RFC 2822               | Sun, 14 Aug 2005 16:13:03 +0000   |
+----------------+------------------------+-----------------------------------+
| DATE_RSS       | RSS                    | Sun, 14 Aug 2005 16:13:03 UTC     |
+----------------+------------------------+-----------------------------------+
| DATE_W3C       | W3C                    | 2005-08-14T16:13:03+0000          |
+----------------+------------------------+-----------------------------------+


local_to_gmt()
==============

Takes a Unix timestamp as input and returns it as GMT. 

.. php:method:: local_to_gmt($time = '')

	:param integer 	$time: Unix timestamp
	:returns: string

Example:

::

	$now = time();
	$gmt = local_to_gmt($now);

gmt_to_local()
==============

Takes a Unix timestamp (referenced to GMT) as input, and converts it to
a localized timestamp based on the timezone and Daylight Saving time
submitted.

.. php:method:: gmt_to_local($time = '', $timezone = 'UTC', $dst = FALSE)

	:param integer 	$time: Unix timestamp
	:param string 	$timezone: timezone
	:param boolean 	$dst: whether DST is active
	:returns: integer

Example

::

	$timestamp = '1140153693';
	$timezone  = 'UM8';
	$daylight_saving = TRUE;
	echo gmt_to_local($timestamp, $timezone, $daylight_saving);


.. note:: For a list of timezones see the reference at the bottom of this page.


mysql_to_unix()
===============

Takes a MySQL Timestamp as input and returns it as Unix. 

.. php:method:: mysql_to_unix($time = '')

	:param integer 	$time: Unix timestamp
	:returns: integer

Example

::

	$mysql = '20061124092345';
	$unix = mysql_to_unix($mysql);

unix_to_human()
===============

Takes a Unix timestamp as input and returns it in a human readable
format with this prototype

.. php:method:: unix_to_human($time = '', $seconds = FALSE, $fmt = 'us')

	:param integer 	$time: Unix timestamp
	:param boolean 	$seconds: whether to show seconds
	:param string 	$fmt: format: us or euro
	:returns: integer

Example

::

	YYYY-MM-DD HH:MM:SS AM/PM

This can be useful if you need to display a date in a form field for
submission.

The time can be formatted with or without seconds, and it can be set to
European or US format. If only the timestamp is submitted it will return
the time without seconds formatted for the U.S. Examples

::

	$now = time();
	echo unix_to_human($now); // U.S. time, no seconds
	echo unix_to_human($now, TRUE, 'us'); // U.S. time with seconds
	echo unix_to_human($now, TRUE, 'eu'); // Euro time with seconds

human_to_unix()
===============

The opposite of the above function. Takes a "human" time as input and
returns it as Unix. This function is useful if you accept "human"
formatted dates submitted via a form. Returns FALSE (boolean) if the
date string passed to it is not formatted as indicated above. 

.. php:method:: human_to_unix($datestr = '')

	:param integer 	$datestr: Date String
	:returns: integer

Example:

::

	$now = time();
	$human = unix_to_human($now);
	$unix = human_to_unix($human);

nice_date()
===========

This function can take a number poorly-formed date formats and convert
them into something useful. It also accepts well-formed dates.

The function will return a Unix timestamp by default. You can,
optionally, pass a format string (the same type as the PHP date function
accepts) as the second parameter. 

.. php:method:: nice_date($bad_date = '', $format = FALSE) 

	:param integer 	$bad_date: The terribly formatted date-like string
	:param string 	$format: Date format to return (same as php date function)
	:returns: string

Example

::

	$bad_time = 199605  // Should Produce: 1996-05-01
	$better_time = nice_date($bad_time,'Y-m-d');
	$bad_time = 9-11-2001 // Should Produce: 2001-09-11
	$better_time = nice_date($human,'Y-m-d');

timespan()
==========

Formats a unix timestamp so that is appears similar to this

::

	1 Year, 10 Months, 2 Weeks, 5 Days, 10 Hours, 16 Minutes

The first parameter must contain a Unix timestamp. The second parameter
must contain a timestamp that is greater that the first timestamp. If
the second parameter empty, the current time will be used. The third 
parameter is optional and limits the number of time units to display. 
The most common purpose for this function is to show how much time has 
elapsed from some point in time in the past to now. 

.. php:method:: timespan($seconds = 1, $time = '', $units = '')

	:param integer 	$seconds: a number of seconds
	:param string 	$time: Unix timestamp
	:param integer 	$units: a number of time units to display
	:returns: string

Example

::

	$post_date = '1079621429';
	$now = time();
	$units = 2;
	echo timespan($post_date, $now, $units);

.. note:: The text generated by this function is found in the following language
	file: language/<your_lang>/date_lang.php

days_in_month()
===============

Returns the number of days in a given month/year. Takes leap years into
account. 

.. php:method:: days_in_month($month = 0, $year = '')

	:param integer 	$month: a numeric month
	:param integer 	$year: a numeric year
	:returns: integer

Example

::

	echo days_in_month(06, 2005);

If the second parameter is empty, the current year will be used.

timezones()
===========

Takes a timezone reference (for a list of valid timezones, see the
"Timezone Reference" below) and returns the number of hours offset from
UTC.

.. php:method:: timezones($tz = '')

	:param string 	$tz: a numeric timezone
	:returns: string

Example

::

	echo timezones('UM5');


This function is useful when used with `timezone_menu()`.

timezone_menu()
===============

Generates a pull-down menu of timezones, like this one:


.. raw:: html

	<form action="#">
		<select name="timezones">
			<option value='UM12'>(UTC -12:00) Baker/Howland Island</option>
			<option value='UM11'>(UTC -11:00) Samoa Time Zone, Niue</option>
			<option value='UM10'>(UTC -10:00) Hawaii-Aleutian Standard Time, Cook Islands, Tahiti</option>
			<option value='UM95'>(UTC -9:30) Marquesas Islands</option>
			<option value='UM9'>(UTC -9:00) Alaska Standard Time, Gambier Islands</option>
			<option value='UM8'>(UTC -8:00) Pacific Standard Time, Clipperton Island</option>
			<option value='UM7'>(UTC -7:00) Mountain Standard Time</option>
			<option value='UM6'>(UTC -6:00) Central Standard Time</option>
			<option value='UM5'>(UTC -5:00) Eastern Standard Time, Western Caribbean Standard Time</option>
			<option value='UM45'>(UTC -4:30) Venezuelan Standard Time</option>
			<option value='UM4'>(UTC -4:00) Atlantic Standard Time, Eastern Caribbean Standard Time</option>
			<option value='UM35'>(UTC -3:30) Newfoundland Standard Time</option>
			<option value='UM3'>(UTC -3:00) Argentina, Brazil, French Guiana, Uruguay</option>
			<option value='UM2'>(UTC -2:00) South Georgia/South Sandwich Islands</option>
			<option value='UM1'>(UTC -1:00) Azores, Cape Verde Islands</option>
			<option value='UTC' selected='selected'>(UTC) Greenwich Mean Time, Western European Time</option>
			<option value='UP1'>(UTC +1:00) Central European Time, West Africa Time</option>
			<option value='UP2'>(UTC +2:00) Central Africa Time, Eastern European Time, Kaliningrad Time</option>
			<option value='UP3'>(UTC +3:00) Moscow Time, East Africa Time</option>
			<option value='UP35'>(UTC +3:30) Iran Standard Time</option>
			<option value='UP4'>(UTC +4:00) Azerbaijan Standard Time, Samara Time</option>
			<option value='UP45'>(UTC +4:30) Afghanistan</option>
			<option value='UP5'>(UTC +5:00) Pakistan Standard Time, Yekaterinburg Time</option>
			<option value='UP55'>(UTC +5:30) Indian Standard Time, Sri Lanka Time</option>
			<option value='UP575'>(UTC +5:45) Nepal Time</option>
			<option value='UP6'>(UTC +6:00) Bangladesh Standard Time, Bhutan Time, Omsk Time</option>
			<option value='UP65'>(UTC +6:30) Cocos Islands, Myanmar</option>
			<option value='UP7'>(UTC +7:00) Krasnoyarsk Time, Cambodia, Laos, Thailand, Vietnam</option>
			<option value='UP8'>(UTC +8:00) Australian Western Standard Time, Beijing Time, Irkutsk Time</option>
			<option value='UP875'>(UTC +8:45) Australian Central Western Standard Time</option>
			<option value='UP9'>(UTC +9:00) Japan Standard Time, Korea Standard Time, Yakutsk Time</option>
			<option value='UP95'>(UTC +9:30) Australian Central Standard Time</option>
			<option value='UP10'>(UTC +10:00) Australian Eastern Standard Time, Vladivostok Time</option>
			<option value='UP105'>(UTC +10:30) Lord Howe Island</option>
			<option value='UP11'>(UTC +11:00) Magadan Time, Solomon Islands, Vanuatu</option>
			<option value='UP115'>(UTC +11:30) Norfolk Island</option>
			<option value='UP12'>(UTC +12:00) Fiji, Gilbert Islands, Kamchatka Time, New Zealand Standard Time</option>
			<option value='UP1275'>(UTC +12:45) Chatham Islands Standard Time</option>
			<option value='UP13'>(UTC +13:00) Phoenix Islands Time, Tonga</option>
			<option value='UP14'>(UTC +14:00) Line Islands</option>
		</select>
	</form>


This menu is useful if you run a membership site in which your users are
allowed to set their local timezone value.

The first parameter lets you set the "selected" state of the menu. For
example, to set Pacific time as the default you will do this

.. php:method:: timezone_menu($default = 'UTC', $class = "", $name = 'timezones')

	:param string 	$default: timezone
	:param string	$class: classname
	:param string	$name: menu name
	:returns: string

Example: 

::

	echo timezone_menu('UM8');

Please see the timezone reference below to see the values of this menu.

The second parameter lets you set a CSS class name for the menu.

.. note:: The text contained in the menu is found in the following
	language file: `language/<your_lang>/date_lang.php`


Timezone Reference
==================

The following table indicates each timezone and its location.

Note some of the location lists have been abridged for clarity and formatting.

+------------+----------------------------------------------------------------+
| Time Zone  | Location                                                       |
+============+================================================================+
| UM12       | (UTC - 12:00) Baker/Howland Island	                          |
+------------+----------------------------------------------------------------+
| UM11       | (UTC - 11:00) Samoa Time Zone, Niue						      |
+------------+----------------------------------------------------------------+
| UM10       | (UTC - 10:00) Hawaii-Aleutian Standard Time, Cook Islands	  |
+------------+----------------------------------------------------------------+
| UM95       | (UTC - 09:30) Marquesas Islands							      |
+------------+----------------------------------------------------------------+
| UM9        | (UTC - 09:00) Alaska Standard Time, Gambier Islands		      |
+------------+----------------------------------------------------------------+
| UM8        | (UTC - 08:00) Pacific Standard Time, Clipperton Island	      |
+------------+----------------------------------------------------------------+
| UM7        | (UTC - 11:00) Mountain Standard Time						      |
+------------+----------------------------------------------------------------+
| UM6        | (UTC - 06:00) Central Standard Time						      |
+------------+----------------------------------------------------------------+
| UM5        | (UTC - 05:00) Eastern Standard Time, Western Caribbean		  |
+------------+----------------------------------------------------------------+
| UM45       | (UTC - 04:30) Venezuelan Standard Time					      |
+------------+----------------------------------------------------------------+
| UM4        | (UTC - 04:00) Atlantic Standard Time, Eastern Caribbean		  |
+------------+----------------------------------------------------------------+
| UM35       | (UTC - 03:30) Newfoundland Standard Time					      |
+------------+----------------------------------------------------------------+
| UM3        | (UTC - 03:00) Argentina, Brazil, French Guiana, Uruguay	      |
+------------+----------------------------------------------------------------+
| UM2        | (UTC - 02:00) South Georgia/South Sandwich Islands		      |
+------------+----------------------------------------------------------------+
| UM1        | (UTC -1:00) Azores, Cape Verde Islands						  |
+------------+----------------------------------------------------------------+
| UTC        | (UTC) Greenwich Mean Time, Western European Time				  |
+------------+----------------------------------------------------------------+
| UP1        | (UTC +1:00) Central European Time, West Africa Time			  |
+------------+----------------------------------------------------------------+
| UP2        | (UTC +2:00) Central Africa Time, Eastern European Time		  |
+------------+----------------------------------------------------------------+
| UP3        | (UTC +3:00) Moscow Time, East Africa Time			  		  |
+------------+----------------------------------------------------------------+
| UP35       | (UTC +3:30) Iran Standard Time								  |
+------------+----------------------------------------------------------------+
| UP4        | (UTC +4:00) Azerbaijan Standard Time, Samara Time			  |
+------------+----------------------------------------------------------------+
| UP45       | (UTC +4:30) Afghanistan										  |
+------------+----------------------------------------------------------------+
| UP5        | (UTC +5:00) Pakistan Standard Time, Yekaterinburg Time		  |
+------------+----------------------------------------------------------------+
| UP55       | (UTC +5:30) Indian Standard Time, Sri Lanka Time				  |
+------------+----------------------------------------------------------------+
| UP575      | (UTC +5:45) Nepal Time										  |
+------------+----------------------------------------------------------------+
| UP6        | (UTC +6:00) Bangladesh Standard Time, Bhutan Time, Omsk Time   |
+------------+----------------------------------------------------------------+
| UP65       | (UTC +6:30) Cocos Islands, Myanmar							  |
+------------+----------------------------------------------------------------+
| UP7        | (UTC +7:00) Krasnoyarsk Time, Cambodia, Laos, Thailand, Vietnam|
+------------+----------------------------------------------------------------+
| UP8        | (UTC +8:00) Australian Western Standard Time, Beijing Time	  |
+------------+----------------------------------------------------------------+
| UP875      | (UTC +8:45) Australian Central Western Standard Time		      |
+------------+----------------------------------------------------------------+
| UP9        | (UTC +9:00) Japan Standard Time, Korea Standard Time, Yakutsk  |
+------------+----------------------------------------------------------------+
| UP95       | (UTC +9:30) Australian Central Standard Time					  |
+------------+----------------------------------------------------------------+
| UP10       | (UTC +10:00) Australian Eastern Standard Time, Vladivostok Time|
+------------+----------------------------------------------------------------+
| UP105      | (UTC +10:30) Lord Howe Island								  |
+------------+----------------------------------------------------------------+
| UP11       | (UTC +11:00) Magadan Time, Solomon Islands, Vanuatu            |
+------------+----------------------------------------------------------------+
| UP115      | (UTC +11:30) Norfolk Island									  |
+------------+----------------------------------------------------------------+
| UP12       | (UTC +12:00) Fiji, Gilbert Islands, Kamchatka, New Zealand     |
+------------+----------------------------------------------------------------+
| UP1275     | (UTC +12:45) Chatham Islands Standard Time					  |
+------------+----------------------------------------------------------------+
| UP13       | (UTC +13:00) Phoenix Islands Time, Tonga						  |
+------------+----------------------------------------------------------------+
| UP14       | (UTC +14:00) Line Islands									  |
+------------+----------------------------------------------------------------+