Call_user_func_array() expects parameter 1 to be a valid callback (Event handler system)

Question

I'm trying to make a system which handles supplied data and calls the functions assigned to them in an array with addHandler().

Code:

class Test {

    public $arrHandlers = array();

    public function addHandler($action, $function) {
        $this->arrHandlers[$action] = $function;
    }

    public function handleData($data) {
        $data   = explode("/", $data);
        $action = array_shift($data);
        if(isset($this->arrHandlers[$action])) {
            call_user_func_array($this->arrhandlers[$action], array($data));
        }
    }
}

function testFunc() {
    echo implode(" ", func_get_args());
}

$obj  = new Test();
$data = "egg/I/like/cheese";
$obj->addHandler("egg", "testFunc");
$obj->handleData($data);

What it outputs:

Warning: call_user_func_array() expects parameter 1 to be a valid callback, no array or string given on line 13

What I want it to output:

I like cheese

`$this->arrHandlers != $this->arrhandlers`. Do you have `E_NOTICE` displaying in your `error_reporting`? You should be getting an undefined property `Test::$arrhandlers` before the warning about `call_user_func_array()` — Michael Berkowski, Feb 17 '14 at 20:32
@MichaelBerkowski: hehe, yeah, including the NOTICE edit, once again in sync ;) I've just deleted mine, it felt way too much like a plain copy ;) — Wrikken, Feb 17 '14 at 20:34
It should be `call_user_func_array($this->arrHandlers[$action], $data);`. — gen_Eric, Feb 17 '14 at 20:34
@MichaelBerkowski Can't believe I didn't notice that. Added `error_reporting(E_ALL)` and fixed the caps mistake. This is what I now get: `Notice: Array to string conversion on line 21 Array` . Line 21 is `echo implode(" ", func_get_args());` — James, Feb 17 '14 at 20:37
Per @RocketHazmat's comment -that's the crux of it, after fixing the property casing on `arrHandlers`. I've tested it working with that implementation. — Michael Berkowski, Feb 17 '14 at 20:37
@Will it's `$data`, not `array($data)` as the second arg to `call_user_func_array()`. — Michael Berkowski, Feb 17 '14 at 20:43

score 2 · Answer 1 · answered Feb 18 '14 at 15:48

Working code:

class Test {

    public $arrHandlers = array();

    public function addHandler($action, $function) {
        $this->arrHandlers[$action] = $function;
    }

    public function handleData($data) {
        $data   = explode("/", $data);
        $action = array_shift($data);
        if(isset($this->arrHandlers[$action])) {
            call_user_func_array($this->arrHandlers[$action], $data);
        }
    }
}

function testFunc() {
    echo implode(" ", func_get_args());
}

$obj  = new Test();
$data = "egg/I/like/cheese";
$obj->addHandler("egg", "testFunc");
$obj->handleData($data);

I put 'arrhandlers' instead of 'arrHandlers' and passed $data as 'array($data)' instead of just '$data' to call_user_func_array().

Call_user_func_array() expects parameter 1 to be a valid callback (Event handler system)

1 Answers1