How to fix PHP preg_replace() faulty result order? - php

Question

The faulty result I get now is: 17th of July, 2011Today is .
function finclude($file){
include($file);
}
$str = "Today is {include 'date.php'}.";
echo preg_replace("/\{include '(.*)\'}/e", 'finclude("$1")', $str);
date.php :
<?php echo date('jS \of F'); ?>, 2011
Expected result: Today is 17th of July.

Answer 1

function finclude($file){
return include($file);
}
<?php return date('jS \of F'); ?>
Result isn't expected because You print date, then finclude return null, then you print "Today is "+finclude

Answer 2

What you call faulty in your result order is actually caused by the execution order of your statements:
echo preg_replace("/\{include '(.*)\'}/e", 'finclude("$1")', $str);
Will start the output (echo) and then call the preg_replace function. In which you make use of the e - eval modifier to execute code, namely the function finclude.
So finclude get's executed earlier than preg_replace will return it's result.
So if finclude does output on its own, it will be displayed in front of the result of preg_replace.
Knowing this is half the solution to your problem. It's much likely you didn't intend this output order (your expected result differs) and you just wanted to make finclude return a value instead of outputting something. To convert output into a return value you can make use of an output buffer:
function finclude($file){
ob_start();
include($file);
return ob_get_clean();
}
$str = "Today is {include 'date.php'}.";
echo preg_replace("/\{include '(.*)\'}/e", 'finclude("$1")', $str);
This will ensure that every output within finclude will be returned as a return value instead.
That done you can re-use existing code/includes that normally outputs within your search and replace operation. However using the e modifier always is dangerous and it normally should be prevented. So take care.

Answer 3

i think you need to put <?php return date('jS \of F'); ?> in date.php