How to do an If-Modified-Since request

Hello,

How can I do an If-Modified-Since request with PHP to see if a webpage has been recently changed or not?

 

<?php

// file to check (with path)
$filename = "filename.php";

// what date you want to check against (ie July 1, 2007):
$date_check = mktime(0, 0, 0, 7, 1, 2007);

$mod_date = date("Y-m-d h:i",filemtime($filename));
$date_since = date("Y-m-d h:i",$date_check);

if ($mod_date > $date_since)
{
    //whatever you wanna do here, e.g.
    echo $filename . " has been modified since: " . $date_since;
}
else { echo $filename . " has not been modified since: " . $date_since; }

?> 

PHP:

 

Just to clarify, do you want to get the date of a local or remote file?

If you want to get the remote date, have a look at this thread.
http://forums.digitalpoint.com/showthread.php?t=326547

And james_r, there is no need to convert the timestamps into a date format. You can directly compare the timestamps.

 

good catch nico, i had done the conversion to easily display in the echo statement.. but it really wasn't necessary, could have done it just once in the echo.