Table of Contents
The Zend_Date component offers a detailed, but simple API for manipulating dates and times. Its
methods accept a wide variety of types of information, including date parts, in numerous combinations yielding
many features and possibilities above and beyond the existing PHP date related functions. For the very latest
manual updates, please see
our online manual
(frequently synced to Subversion)
.
Although simplicity remains the goal, working with localized dates and times while modifying, combining, and
comparing parts involves some unavoidable complexity. Dates, as well as times, are often written differently in
different locales. For example, some place the month first, while other write the year first when expressing
calendar dates. For more information about handling localization and normalization, please refer to
Zend_Locale
.
Zend_Date also supports abbreviated names of months in many languages. Zend_Locale
facilitates the normalization of localized month and weekday names to timestamps, which may, in turn, be shown
localized to other regions.
Before using any date related functions in PHP or the Zend Framework, first make certain your application
has a correct default timezone, by either setting the TZ environment variable, using the
date.timezone php.ini setting, or using
date_default_timezone_set()
. In PHP, we can adjust all date and time related functions to work for a particular user by setting a
default timezone according to the user's expectations. For a complete list of timezone settings, see the
CLDR Timezone Identifier List
.
Example 8.1. Setting a default timezone
<?php
date_default_timezone_set('America/Los_Angeles'); // timezone for an American in California
date_default_timezone_set('Europe/Berlin'); // timezone for a German in Germany
?>
When creating Zend_Date instances, their timezone will automatically become the current default timezone! Thus, the timezone setting will account for any Daylight Savings Time (DST) in effect, eliminating the need to explicitly specify DST.
Zend_Date offers the following features, which extend the scope of PHP date functions:
Simple API
Zend_Date offers a very simple API, which combines the best of date/time functionality
from four programming languages. It is possible, for example, to add or compare two times within a
single row.
Completely internationalized
All full and abbreviated names of months and weekdays are supported for more than 130 languages. Methods support both input and the output of dates using the localized names of months and weekdays, in the conventional format associated with each locale.
Unlimited timestamps
Although PHP 5.2 docs state, "The valid range of a timestamp is typically from Fri, 13 Dec 1901
20:45:54 GMT to Tue, 19 Jan 2038 03:14:07 GMT," Zend_Date supports a nearly unlimited
range, with the help of the BCMath extension. If BCMath is not avaiable, then Zend_Date will have
reduced support only for timestamps within the range of the float type supported by
your server. "The size of a float is platform-dependent, although a maximum of ~1.8e308 with a
precision of roughly 14 decimal digits is a common value (that's 64 bit IEEE format)." [
http://www.php.net/float
]. Additionally, inherent limitations of float data types, and rounding error of float numbers
may introduce errors into calculations. To avoid these problems, the ZF i18n components use
BCMath extension, if available.
Support for ISO_8601 date specifications
ISO_8601 date specifications are supported. Even partially compliant ISO_8601 date specifications
will be identified. These date formats are particularly useful when working with databases. For
example, even though MsSQL and
MySQL
differ a little from each other, both are supported by Zend_Date using the
Zend_Date::ISO_8601
format specification constant. When date strings conform to "Y/m/d" or "Y-m-d H:i:s", according to
PHP date() format tokens, use Zend_Date's built-in support for ISO 8601 formatted dates.
Calculate sunrise and sunset
For any place and day, the times for sunrise and sunset can be displayed, so that you won't miss a single daylight second for working on your favorite PHP project :)