override_function

(PECL apd >= 0.2)

override_function — 組み込みの関数を上書きする

説明

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

シンボルテーブルを書き換えることで、組み込みの関数を上書きします

パラメータ

function_name

上書きする関数。

function_args

関数への引数をカンマ区切りの文字列で指定します。

通常は、このパラメータだけでなく function_code パラメータも (シングルクォート区切りの文字列で) 指定することでしょう。シングルクォートで囲んだ文字列を使用する理由は、変数名がパースされないようにするためです。ダブルクォートを使用するなら、変数名をエスケープして \$your_var のようにしなければなりません。

function_code

関数の新しいコード。

返り値

成功した場合に TRUE を、失敗した場合に FALSE を返します。

例

例1 override_function() の例


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

rename_function

apd_set_session

[edit] Last updated: Fri, 10 Feb 2012

add a note User Contributed Notes override_function

taher at unixwars dot com 28-Nov-2008 08:08


I had the same problem and, since the __overriden__() name is hardcoded, I simply ended up renaming that one. I use it like this:





<?php


function _dbslayer_map()


{


    $substs = array(


        'mysql_connect' => 'dbslayer_mysql_connect($host, $user, $pass, $new_link, $client_flags)',


        'mysql_fetch_array' => 'dbslayer_mysql_fetch_array($result, $result_type)',


        'mysql_query' => 'dbslayer_mysql_query($query, $link_identifier)'


            );





    $args = array(


        'mysql_connect' => '$host = NULL, $user = NULL, $pass = NULL, $new_link = false, $client_flags = 0',


        'mysql_fetch_array' => '&$result, $result_type = MYSQL_BOTH',


        'mysql_query' => '$query, $link_identifier = DEFAULT_LINK'


            );





    foreach ($substs as $func => $ren_func) {


        override_function($func, $args[$func], "return $substs[$func];");


              rename_function("__overridden__", $ren_func);


      }


}


?>





So far, so good.

pagan at o2 dot pl 24-Oct-2008 12:34


There is not chance to override 2 or more functions, because of the error:

Fatal error: Cannot redeclare __overridden__()

rojaro at gmail dot com 20-Sep-2005 12:13


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)));');

}

?>

php at undeen dot com 10-Mar-2005 12:07


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.

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