[SOLVED] PHP: call_user_func

[xenophobia]

I have a question:

 

I read on this:

http://my.php.net/manual/en/function.call-user-func.php

 

The doc said, if there is any problem on calling the user's function, it will return false. So i put this:

$return_val = @call_user_func('my_function');

 

if($return_val === false) { die("ERROR!"); }

 

How if my function is returning a boolean?

function my_function() {

  if (//some expression here...) { return false; }

}

 

It is not calling error. My function is just returning an false bool value. How am I going to know it is error or returning value?

[Daniel0]

You could just not call it if it doesn't exist.

 

$functionName = 'foo_bar_baz';

if (function_exists($functionName)) {
$returnValue = call_user_func($functionName);
}
else {
echo 'error';
}

[xenophobia]

What if the error is not caused by function not exist?

 

Like:

 

function my_function($param_1) {

  return false;

}

 

call_user_func("my_function");

 

which missed 1 parameter.

[Daniel0]

Then you can use reflection. This should work:

 

<?php
function callFunction($callback, array $arguments = array())
{
if (is_array($callback)) {
	if (count($callback) == 2 && (is_string($callback[0]) || is_object($callback[0]) && is_string($callback[1]))) {
		$class = is_object($callback[0]) ? get_class($callback[0]) : $callback[0];
		$function = $callback[1];

		$reflection = new ReflectionMethod($class, $function);
	}
	else {
		throw new InvalidArgumentException('Invalid callback');
	}
}
else {
	$reflection = new ReflectionFunction($callback);

}

$params = $reflection->getParameters();
foreach ($params as $i => $param) {
	if (!$param->isOptional() && !isset($arguments[$i])) {
		throw new RuntimeException('Missing required argument ' . ($i + 1));
	}
}

if (is_array($callback)) {
	if (!is_object($callback[0]) && !$reflection->isStatic()) {
		throw new RuntimeException('Cannot statically call a non-static method');
	}
	else if (!is_object($callback[0])) {
		return call_user_func_array($callback, $arguments);
	}
	else {
		$return = $reflection->invokeArgs($callback[0], $arguments);
	}
}
else {
	$return = $reflection->invokeArgs($arguments);
}

return $return;
}

 

The $callback supports the regular callback format except the Class::method() notation.

 

Exceptions are good because they can be caught. Errors cannot easily be caught.

[xenophobia]

Wow! Thx for your effort. That should work. So I will just catch the exception and know whether it is throwing an error or returning a value(FALSE).

 

Maybe they should make it a built-in function: call_function().