override_function

(PECL apd >= 0.2)

override_functionOverrides built-in functions

Descrierea

bool override_function ( string $function_name , string $function_args , string $function_code )

Overrides built-in functions by replacing them in the symbol table.

Parametri

function_name

The function to override.

function_args

The function arguments, as a comma separated string.

Usually you will want to pass this parameter, as well as the function_code parameter, as a single quote delimited string. The reason for using single quoted strings, is to protect the variable names from parsing, otherwise, if you use double quotes there will be a need to escape the variable names, e.g. \$your_var.

function_code

The new code for the function.

Valorile întoarse

Întoarce valoarea TRUE în cazul succesului sau FALSE în cazul eșecului.

Exemple

Example #1 override_function() example

<?php
override_function
('test''$a,$b''echo "DOING TEST"; return $a * $b;');
?>

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User Contributed Notes 5 notes

up
16
php at undeen dot com
9 years ago
I thought the example was not very helpful, because it doesn't even override the function with another function.
My question was: If I override a function, can I call the ORIGINAL function within the OVERRIDING function?
ie, can I do this:
<?php
override_function
('strlen', '$string', 'return override_strlen($string);');
function
override_strlen($string){
        return
strlen($string); 
}
?>
The answer: NO, you will get a segfault.

HOWEVER, if you use rename_function to rename the original function to a third name, then call the third name in the OVERRIDING function, you will get the desired effect:
<?php
rename_function
('strlen', 'new_strlen');
override_function('strlen', '$string', 'return override_strlen($string);');

function
override_strlen($string){
        return
new_strlen($string); 
}
?>

I plan to use this functionality to generate log reports every time a function is called, with the parameters, time, result, etc... So to wrap a function in logging, that was what I had to do.
up
1
tothandor at gmail dot com
5 months ago
Overriden function name becomes __overridden__(). That's why you can't override two function, and that's how you can use the original function in the override.
up
1
Darien H
10 months ago
Please note that this function (as of v1.0.1 in PHP 5.3) will <b>not</b> override some important built-in "functions". Specifically, those which are actually statements/keywords, such as:

    require
    include
    require_once
    include_once
    echo
    print

I was hoping to use it to trace the chains of require/include activity among files in a large legacy project, but it seems APD will not do what I need.
up
-1
rojaro at gmail dot com
9 years ago
Since Apache 1 & 2 use diffrent methods (Unicode vs. UTF8) on Win32 platforms to encode urls, i've implemented the following workaround to get around this "bug" (which is actually known behaviour and wont get fixed). This workaround is really usefull when writing PHP scripts which have to work on all platforms (Windows, Linux, BSD etc.), must process URLs and must work under both Apache versions.

<?php
$httpd
= explode(' ', $_SERVER['SERVER_SOFTWARE']);
if(
substr($httpd[0], 0, 6)=='Apache' && substr($httpd[0], 7, 1)==2 && $httpd[1]=='(Win32)')
{
  if(isset(
$_SERVER['REQUEST_URI'])) $_SERVER['REQUEST_URI'] = str_replace('%2F', '/', rawurlencode(utf8_decode(rawurldecode($_SERVER['REQUEST_URI']))));
  if(isset(
$_SERVER['REDIRECT_URL'])) $_SERVER['REDIRECT_URL'] = str_replace('%2F', '/', rawurlencode(utf8_decode(rawurldecode($_SERVER['REDIRECT_URL']))));
 
override_function('urlencode', '$url', 'return str_replace("%2F", "/", rawurlencode(utf8_encode($url)));');
}
?>
up
-1
pagan at o2 dot pl
6 years ago
There is not chance to override 2 or more functions, because of the error:
Fatal error: Cannot redeclare __overridden__()
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