(PECL apd >= 0.2)
override_function — Overrides built-in functions
$function_name
, string $function_args
, string $function_code
)Overrides built-in functions by replacing them in the symbol table.
function_name
The function to override.
function_args
The function arguments, as a comma separated string.
Usually you will want to pass this parameter, as well as the
function_code parameter, as a single quote
delimited string. The reason for using single quoted strings, is to
protect the variable names from parsing, otherwise, if you use double
quotes there will be a need to escape the variable names, e.g.
\$your_var.
function_code
The new code for the function.
成功时返回 TRUE， 或者在失败时返回 FALSE。
Example #1 override_function() example
<?php
override_function('test', '$a,$b', 'echo "DOING TEST"; return $a * $b;');
?>
taher at unixwars dot com (2008-11-28 08:08:39)
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 (2008-10-24 00:34:05)
There is not chance to override 2 or more functions, because of the error:
Fatal error: Cannot redeclare __overridden__()
rojaro at gmail dot com (2005-09-20 12:13:09)
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 (2005-03-10 12:07:11)
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.