override_function()
(PECL apd >= 0.2)
Overrides built-in functions
说明
override_function(string $function_name,string $function_args,string $function_code): bool
Overrides built-in functions by replacing them in the symbol table.
参数
- $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_codeparameter, 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.
- $function_code
The new code for the function.
返回值
成功时返回TRUE
,或者在失败时返回FALSE
。
范例
Example #1 override_function() example
<?php override_function('test', '$a,$b', 'echo "DOING TEST"; return $a * $b;'); ?>
I thought the example was not very helpful, because it doesn't even override the function with another function. My question was: If I override a function, can I call the ORIGINAL function within the OVERRIDING function? ie, can I do this: <?php override_function('strlen', '$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($string); } ?> I plan to use this functionality to generate log reports every time a function is called, with the parameters, time, result, etc... So to wrap a function in logging, that was what I had to do.
Overriden function name becomes __overridden__(). That's why you can't override two function, and that's how you can use the original function in the override.
Of course you can't overwrite "functions" like require_once or print as they are not really a function but a language construct.
You can find Excepción - Call to undefined function override_function() due to Function override_function is part of PECL Extension. Configure PECL
Please note that this function (as of v1.0.1 in PHP 5.3) will <b>not</b> override some important built-in "functions". Specifically, those which are actually statements/keywords, such as: require include require_once include_once echo print I was hoping to use it to trace the chains of require/include activity among files in a large legacy project, but it seems APD will not do what I need.
Yes you can if you rename the overridden function. So you first rename original function, then override it and finally rename the overridden one, something like this: rename_function('feof', 'real_feof'); override_function('feof', '$handle', 'return true;'); rename_function("__overridden__", 'dummy_feof');
There is not chance to override 2 or more functions, because of the error: Fatal error: Cannot redeclare __overridden__()
Maybe it's better to use overwritten function inside the override to code something like this : <?php rename_function('myFunction','original_myFunction'); override_function('myFunction','$arg,…,$argN','return override_myFunction($arg,…,$argN);'); ?> You may then give somehow "inheritance" to override_myFunction … As a parent : <?php function override_myFunction($arg,…,$argN) { $result=original_myFunction($arg,…,$argN)); /* CODE that manipulates the result */ return $result; } ?> As a child : <?php function override_myFunction($arg,…,$argN) { /* CODE that manipulates the arguments */ return original_myFunction($arg,…,$argN)); } ?>