I get a bit confused over all the nice things laravel has to offer in terms of the IOC container and facades. Since I'm not an experienced programmer it gets overwhelming to learn.
I was wondering, what is the difference between these two examples:
A facade to 'Foo' and registered in the container via App::bind()
A facade to 'Foo' and registered in the container via App::singleton()
In my best understanding Foo::method()
will be rewritten as $app->make['foo']->method()
so in the first example multiple instances of the Foo
class will be created and in the second example, since it's bound via an App::singleton()
, the same instance of Foo
will be returned every time a Method on that object is called.
I'm sorry if the answer to this question is to obvious, but I can't find any confirmation on this matter and nowhere this is clearly explained.
It's exactly like that.
A very simple proof is to test out the behavior. Since the Laravel Application simply extends Illuminate\Container\Container
, we'll use just the container (in my case I even only added the container as a dependency to my composer.json) to test.
require __DIR__ . '/vendor/autoload.php';
class FirstClass
{
public $value;
}
class SecondClass
{
public $value;
}
// Test bind()
$container = new Illuminate\Container\Container();
$container->bind('FirstClass');
$instance = $container->make('FirstClass');
$instance->value = 'test';
$instance2 = $container->make('FirstClass');
$instance2->value = 'test2';
echo "Bind: $instance->value vs. $instance2->value\n";
// Test singleton()
$container->singleton('SecondClass');
$instance = $container->make('SecondClass');
$instance->value = 'test';
$instance2 = $container->make('SecondClass');
$instance2->value = 'test2'; // <--- also changes $instance->value
echo "Singleton: $instance->value vs. $instance2->value\n";
The result is as expected:
Bind: test vs. test2
Singleton: test2 vs. test2
Might be a dirty proof, but indeed it is one.
All the magic lies in the Container::make
method.
If the binding is registered as shared (which means as singleton), the class instance is returned, otherwise a new instance every time.
Source: https://github.com/laravel/framework/blob/4.2/src/Illuminate/Container/Container.php#L442
BTW, Container::singleton
is the same as Container::bind
with the third parameter set to true.