Access the arguments passed to child method

Question

I have the following:

class bar {

    function __construct(){

         // set $a_from_fire to $a from fire() method arg
         // set $b_from_fire to $b from fire() method arg
    }
}

class foo extends bar {

    function fire ($a, $b){

    }
}

I need to set $a_from_fire and $b_from_fire using the arguments from foo->fire()

So if I do this:

$test = new foo;
$test->fire(1, 2);

These vars will be set:

$a_from_fire == 1; // true
$b_from_fire == 2; // true

I'm not sure exactly what you're trying to do. Can you at least show some non-working code or further description that explains what you want? Also, where is `$a_from_fire` declared? — Reed, Jan 02 '15 at 19:13
I just added some clarification. I am trying to debug a set of classes which are running as jobs in a message queue. They all extend one parent class so I am hoping I can log the arguments passed to each of the child class methods by simply adding a method to the parent class in order to capture the arguments. — phirschybar, Jan 02 '15 at 19:22
perhaps this can be done with something other than __construct ? — phirschybar, Jan 02 '15 at 19:23
I also ran across [this post](http://stackoverflow.com/a/3386948/802469) yesterday which could potentially help, but it didn't sound like it would be helpful given your particular case (since you'd have to rewrite some code outside the parent class). — Reed, Jan 03 '15 at 14:09

score 0 · Answer 1 · answered Jan 02 '15 at 19:14

This isn't possible because __construct() is called when the object is first instantiated, so fire($a, $b) will always run after __construct()

If you just want to set the variables when fire() is called, simply do:

class bar {
    protected $a_from_fire;
    protected $b_from_fire;
}

class foo extends bar {
    public function fire($a, $b) {
        $this->a_from_fire = $a;
        $this->b_from_fire = $b;
    }
}

score 0 · Accepted Answer · answered Jan 02 '15 at 19:53

I don't think you can do it in any "correct" way. My first thought was to use __call, but that of course is only called for undefined functions.

And there's not really any way to dynamically rename the methods, unless you're already using RunKit. (not that I know of or could find anyway).

If it's purely for debug purposes, you could set your own class autoloader to pre-process the files, change the method names, and then use the __call magic method on your parent class.

spl_autoload_register(function($class){
       $hackPath = '/home/_classes/'.$class;
       if (!file_exists($hackPath)){
           $realPath = '/home/classes/'.$class;
           $file = file_get_contents($realPath);
           $processedContent = //use regex or something to prepend all function names with an _.
           file_put_contents($hackPath,$processedContent);
       }


       require_once $hackPath;
    });

Then in your parent class

class parent {

    public function __call($funcName,$arguments){

       $this->myLogFunc($funcName,$arguments);
       //since you prepended with an underscore
       return call_user_func_array('_'.$funcName,$arguments);

    }

This is a terrible way to do what you're asking, but it could work. The pre-processing of files might be slow, but you'd only need to do it if the originals changed (you can use filemtime to check if it's changed).

Access the arguments passed to child method

2 Answers2