Catching fatal errors on type hinted controller methods

Question

Catching fatal errors on type hinted controller methods

dompie Oct '14

Created Oct '14	Last Reply Aug '18	Replies 3	Views 2364	Votes 0

dompie 8.6k

Oct '14

Hello,

I have the following router converter defined:


    $router->addGet(...)
    ->convert('southWest', function($southWest) {
        $sw = explode(',', $southWest);
        try{
            $p = new Point($sw[0], $sw[1]);
        } catch(Exception $e) {
            //Impossible to create instance of Point and senseless to use default values
            $p = NULL
        }
        return $p;
    });

The parameter (Point) will be passed to the following controller method:

    public function fooAction(Point $southWest) {
        ...mycode
    }

In case of an Exception inside the converter, $p = NULL will be returned and then passed to fooAction. Unfortunately then a Catchable fatal error will be thrown by PHP.

Now my questions:

Is it possible to redirect to another action before fooAction will be called with a invalid parameter ? Is it possible to catch the fatal error and call another action? If yes, where should that be done?

Phalcon · Answer 1 · 2014-10-18T16:40:55-07:00

I think those fatal E_RECOVERABLE_ERROR errors cannot be catched by a try/catch:

try {
  class X
  {
          public function b(X $x)
          {
          }
  }

  $a = null;
  $x = new X;
  $x->b($a);
} catch (\Exception $e) {
    // this is never executed
}

PHP Catchable fatal error:  Argument 1 passed to X::b() must be an instance of X, null given, called in /Users/scott/cphalcon/a.php on line 13 and defined in /Users/scott/cphalcon/a.php on line 6

You can create an error handler to handle these kind of errors:

set_error_handler(function($errno, $errstr, $errfile, $errline) {
        if (E_RECOVERABLE_ERROR === $errno) {
                echo "'catched' catchable fatal error\n";
                return true;
        }
        return false;
})

dompie · Answer 2 · 2014-10-19T11:17:54-07:00

Yes, indeed. They can not be catched. I was hoping there is a build in way in phalcon that makes it possible to elegantly call/redirect to another action in that case. I'll then take another way and send an invalid request response right from the catch block before die()ing.

Thanks

sventunus · Answer 3 · 2014-10-19T14:10:10-07:00

How about:

$sw = explode(',', $southWest)
try {
    $p = new Point($sw[0], $sw[1]);
    if(!get_class(p) === Point) {
        // call other action here
    }
} catch(Exception $e) {
    //Impossible to create instance of Point and senseless to use default values
    $p = NULL
}
return $p;

?

dompie · Answer 4 · 2014-10-19T21:21:15-07:00

My point class will throw an exception when coordinates are invalid (e.g. 837.23472,-414.128371). I can't do that.

casaulenbo · Answer 5 · 2018-08-04T10:14:44-07:00

My point class will throw an exception when coordinates are invalid (e.g. 837.23472,-414.128371). I can't do that.

in PHP7 now you can using try catch to catch up PHP FATAL ERROR try this:

try {
do somethings will raise falta error
} catch (Error $e) {
now you can catch me :)
}

Hope this help!