override_function

Overrides built-in functions (PECL apd:0.2-1.0.1)
bool override_function ( string function_name, string function_args, string function_code )

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

Parameters

function_name

The function to override.

function_args

The function arguments, as a coma 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.

Return Values

Returns TRUE on success or FALSE on failure.

Examples

Example 231. override_function() example

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<?php

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

Code Examples / Notes » override_php

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)));'); } ?>

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.

override_function

Overrides built-in functions (PECL apd:0.2-1.0.1) bool override_function ( string function_name, string function_args, string function_code )

Parameters

Return Values

Examples

Example 231. override_function() example

Code Examples / Notes » override_php

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Overrides built-in functions (PECL apd:0.2-1.0.1)
bool override_function ( string function_name, string function_args, string function_code )