Recipe 19.2 Getting and Setting File Timestamps
19.2.1 Problem
You want to know when a file was last
accessed or changed, or you want to update a file's
access or change time; for example, you want each page on your web
site to display when it was last modified.
19.2.2 Solution
The fileatime(
)
, filemtime( ), and
filectime( ) functions return the time of last
access, modification, and metadata change of a file:
$last_access = fileatime('larry.php');
$last_modification = filemtime('moe.php');
$last_change = filectime('curly.php');
The touch( ) function changes a
file's modification time:
touch('shemp.php'); // set modification time to now
touch('joe.php',$timestamp); // set modification time to $timestamp
19.2.3 Discussion
The fileatime( ) function returns the last time a
file was opened for reading or writing. The filemtime(
) function returns the last time a file's
contents were changed. The filectime( ) function
returns the last time a file's contents or metadata
(such as
owner or permissions) were changed.
Each function returns the time as an
epoch
timestamp.
A file's modification time can be updated with
touch( ). Without a second argument,
touch( ) sets the modification time to the
current date and time. To set a file's modification
time to a specific value, pass that value as an epoch timestamp to
touch( ) as a second argument.
This code prints the time a page on your web site was last updated:
print "Last Modified: ".strftime('%c',filemtime($_SERVER['SCRIPT_FILENAME']));
19.2.4 See Also
Documentation on fileatime( ) at http://www.php.net/fileatime,
filemtime( ) at http://www.php.net/filemtime, and
filectime( ) at http://www.php.net/filectime.
|
