在Symfony3 / PHP中通过字符串变量创建新对象

Question

I send variables to my route via an ajax post. Based on the value of my type value I create a new Object, like this:

if($request->get('type') === 'HardwareType'){
    $e = new HardwareType();
}else if($request->get('type') === 'SetupType'){
    $e => new SetupType();
}else{
    new NotFoundHttpException();
}

This gets out of hand quickly even with a switch I think its still "ugly". Is there any way I could do sth. like this:

$e = new $request->get('type')();

Any hint appreciated

EDIT I use the class(es) with this use AppBundle\\Entity\\HardwareType; etc.

Answer 1

you can do this:

$e = $request->get('type');
$class = new $e();

If you need you can add the path or the class like this:

$e = 'AppBundle\Entity\' . $request->get('type');

Obviously you need to add use at the begin of the file and you can check before the new if the class exist or not

Like this:

if (!class_exists($e)) {
   //exception
}

Answer 2

Just use an associative array! Define the acceptable classes, so that other types of class you don't want to allow can't be instantiated!

Then just check the key is in the array, and if so create a new Whatever()!

$types = [
    'HardwareType' => HardwareType::class,
    'etc' => SomeOther::class
];

$getVar = $request->get('type');

// So all you need do is 
if (array_key_exists($getVar, $types)) {
    $e = new $types[$getVar]();
} else {
    throw new NotFoundHttpException();
}