I'm aware that methods can be resolved automatically by Laravel within the controller:
//A
class ScriptsController extends Controller {
public function __construct(Script $scripts){ // Script automatically injected
$this->scripts = $scripts;
}
public function store(Request $request, $id){ // Request automatically injected
// do something
}
}
I simply want to do the same thing with any class or method.
// B1
class MyClass extends Controller {
public function __construct(Bar $bar){ // Bar to be automatically injected
$this->bar = $bar;
}
public function doSomething(Foo $foo, $id){ // Foo to be automatically injected
$foo->do();
}
}
Then somewhere else
// B2
$class = new MyClass(); // without an error
$class2 = new MyClass();
$class2->doSomething(); // ditto
There are tutorials about this but rather than answering this directly they tend to have long explanations about how the service provider works etc.
Is there a simple way to add a line somewhere ( Bind perhaps ?) to have the container resolve the dependencies so that B2 above works?
I don't think you'd be able to do that with that particular syntax. You can have Laravel automatically inject dependencies for your class, but you'd need to resolve it out of the container in any case.
Please see the documentation here for binding: https://laravel.com/docs/5.3/container#binding and further down, resolving classes from the container.
Related
In my controller I am using a class like so:
public function book($id, CalRequest $request)
{
$event = $this->repo->find($id);
(new CalAuthorisation())
->setEvent($event)
->canBook();
$this->booking->book($event, $request);
}
I'm mocking a class like below:
$auth = \Mockery::mock(CalAuthorisation::class)->makePartial();
$this->app->bind(CalAuthorisation::class, function() use ($auth) {
return $auth;
});
$auth->shouldReceive('canBook')->once()->andReturn(true);
However, if I dd within the canBook() function I still get into there. I have a similar mock in place for the CalRequest class which works fine. Any suggestions as to why this isn't working!
Dependency injection is about injecting different implementation into your logic. When using new keyword, PHP will fetch a certain class and only that class. Laravel solves dependency injection through the container, so you have to use the container for it to work.
There is two ways, either use app() or resolve(). Secondly you can inject your classes into methods that are on Laravel classes like jobs, commands, controllers etc. and this will be resolved through the container.
Using resolve().
resolve(new CalAuthorisation())
->setEvent($event)
->canBook();
Injecting it, through the controller method.
public function book($id, CalRequest $request, CalAuthorisation $calAuth)
{
$event = $this->repo->find($id);
$calAuth->setEvent($event)
->canBook();
With Laravel Framework 5.8.36 I'm trying to run a test that calls a controller where the __construct method uses DI, like this:
class SomeController extends Controller {
public function __construct(XYZRepository $xyz_repository)
{
$this->xyz_repository = $xyz_repository;
}
public function doThisOtherThing(Request $request, $id)
{
try {
return response()->json($this->xyz_repository->doTheRepoThing($id), 200);
} catch (Exception $exception) {
return response($exception->getMessage(), 500);
}
}
}
This works fine if I run the code through the browser or call it like an api call in postman, but when I call the doThisOtherThing method from my test I get the following error:
ArgumentCountError: Too few arguments to function App\Http\Controllers\SomeController::__construct(), 0 passed in /var/www/tests/Unit/Controllers/SomeControllerTest.php on line 28 and exactly 1 expected
This is telling me that DI isn't working for some reason when I run tests. Any ideas? Here's my test:
public function testXYZShouldDoTheThing()
{
$some_controller = new SomeController();
$some_controller->doThisOtherThing(...args...);
...asserts...
}
I've tried things like using the bind and make methods on app in the setUp method but no success:
public function setUp(): void
{
parent::setUp();
$this->app->make('App\Repositories\XYZRepository');
}
That's correct. The whole idea of a unit test is that you mock the dependant services so you can control their in/output consistently.
You can create a mock version of your XYZRepository and inject it into your controller.
$xyzRepositoryMock = $this->createMock(XYZRepository::class);
$some_controller = new SomeController($xyzRepositoryMock);
$some_controller->doThisOtherThing(...args...);
This is not how Laravels service container works, when using the new keyword it never gets resolved through the container so Laravel cannot inject the required classes, you would have to pass them yourself in order to make it work like this.
What you can do is let the controller be resolved through the service container:
public function testXYZShouldDoTheThing()
{
$controller = $this->app->make(SomeController::class);
// Or use the global resolve helper
$controller = resolve(SomeController::class);
$some_controller->doThisOtherThing(...args...);
...asserts...
}
From the docs :
You may use the make method to resolve a class instance out of the
container. The make method accepts the name of the class or interface
you wish to resolve:
$api = $this->app->make('HelpSpot\API');
If you are in a location of your code that does not have access to the
$app variable, you may use the global resolve helper:
$api = resolve('HelpSpot\API');
PS:
I am not really a fan of testing controllers like you are trying to do here, I would rather create a feature test and test the route and verify everything works as expected.
Feature tests may test a larger portion of your code, including how
several objects interact with each other or even a full HTTP request
to a JSON endpoint.
something like this:
use Illuminate\Http\Response;
public function testXYZShouldDoTheThing()
{
$this->get('your/route')
->assertStatus(Response::HTTP_OK);
// assert response content is correct (assertJson etc.)
}
I have registered a Paypal service provider:
App\Providers\PaypalHelperServiceProvider::class,
and, when I type hint it in my controller it properly resolves:
public function refund(Request $request, PaypalHelper $paypal) {...
Here is my provider class:
class PaypalHelperServiceProvider extends ServiceProvider
{
protected $defer = true;
public function register()
{
$this->app->bind('App\Helpers\PaypalHelper', function() {
$test = 'test';
return new PaypalHelper();
});
}
public function provides()
{
$test = 'test';
return [App\Helpers\PaypalHelper::class];
}
}
Everything works as expected. Now I wanted to be able to modify controller to take a PayPal interface. I would then update my service provider to conditionally pass in either the real class or a mock one for testing, using the APP_ENV variable to determine which one to use. I put some debuggers into the service provider class and could not get it to ever go in. I thought perhaps that it only loads them on need, so I put a breakpoint inside my controller. The class did resolve, but it still never went into the service provider class! Can someone explain to me why this is the case? Even when I modified the code to pass in a different class type it did not pick up.
EDIT:
Here is the code flow I see when I debug this:
ControllerDispatcher -> resolveClassMethodDependencies -> resolveMethodDependencies -> transformDependency. At this point we have the following laravel code in the RouteDependencyResolveerTrait:
protected function transformDependency(ReflectionParameter $parameter, $parameters, $originalParameters)
{
$class = $parameter->getClass();
// If the parameter has a type-hinted class, we will check to see if it is already in
// the list of parameters. If it is we will just skip it as it is probably a model
// binding and we do not want to mess with those; otherwise, we resolve it here.
if ($class && ! $this->alreadyInParameters($class->name, $parameters)) {
return $this->container->make($class->name);
}
}
Since getClass() always resolves to the interface name, when we call container->make(), it always fails with
Target [App\Helpers\PaypalHelperInterface] is not instantiable.
Change
$this->app->bind('App\Helpers\PaypalHelper', function() {
$test = 'test';
return new PaypalHelper();
});
To
if (app()->environment('testing')) {
$this->app->bind(
PaypalHelperInterface::class,
FakePaypalHelper::class
)
} else {
$this->app->bind(
PaypalHelperInterface::class,
PaypalHelper::class
);
}
I finally found out the issue. My problem was that my provider wasn't being picked up at all. Here was the solution
composer dumpautoload
php artisan cache:clear
https://laravel.io/forum/02-08-2015-laravel-5-service-provider-not-working
I usually use parameters like this:
public function test($parameter)
{
echo 'Parameter value: ' . $parameter;
}
While looking at laravel service container I see this code.
public function __construct(UserRepository $users)
{
$this->users = $users;
}
According to the documentation it uses reflection.But i dont understand.
I dont know how the parameter UserRepository $users works. Is that an alias or something?
This is called type-hinting and is used to inject dependencies in a constructor or to validate the right type of argument is passed to a function. The injection simply means that if the class is called with the make method, Laravel will automatically provide an instance of the class required by your constructor.
For example if you have a function public function something(string $something) it would throw an error if any other type than a String is passed to this function, making sure the right data is used.
From the laravel documentation:
Alternatively, and importantly, you may "type-hint" the dependency in the constructor of a class that is resolved by the container, including controllers, event listeners, queue jobs, middleware, and more. In practice, this is how most of your objects should be resolved by the container.
For example, you may type-hint a repository defined by your application in a controller's constructor. The repository will automatically be resolved and injected into the class:
Laravel has a great service container and it makes all dependency injections, so you don't need to pass a class a parameter, laravel do it for you.
without container you have to pass this parameter
class A {
public $foo;
public function __construct (Foo $foo){
$this->foo
}
$classA = new A((new Foo))
When laravel encounter with these classes, it resolves them.
Also you can define manually these classes using singleton() or bind() methods
$this->app->singleton('FooBar', function($app)
{
return new FooBar($app['SomethingElse']);
});
Or you may use interfaces. You can bind implemented class for to the interface and laravel when encounter with that interfance, it will resolve as you wish
$this->app->bind('App\ICacheManager', 'App\RedisManager');
public $redis;
public function __contruct(ICacheManager $redis){
$this->redis = $redis;
}
for more further check out laravel service container
I am trying to do a hello world service provider with the new Laravel 5.4.
I have created the following service provider file:
//File: app/TestProvider/TestServiceProvider.php
namespace App\TestProvider;
use Illuminate\Support\ServiceProvider;
class TestServiceProvider extends ServiceProvider
{
/**
* Register bindings in the container.
*
* #return void
*/
public function register()
{
$this->app->bind('Test', function ($app) {
return new Test();
});
}
}
I have created a simple class under the same namespace:
//File: app/TestProvider/Test.php
namespace App\TestProvider;
class Test
{
/**
* Register bindings in the container.
*
* #return void
*/
public function helloWorld()
{
echo "hello world";
}
}
The problem is, this is not registering. The register method is executing as when I put a breaker before the 'bind' method, it executes:
public function register()
{
dd("BREAKER");
$this->app->bind('Test', function ($app) {
return new Test();
});
}
So this outputs "BREAKER" as expected. However if I put the breaker in the closure, nothing happens which suggests for some reason, that 'bind' method isn't being executed??
Any ideas?
EDIT:
Just some further info: I know that the Test class is registered and in the correct namespace as I can do:
dd(new Test());
in the registration method, and it outputs the resource id as expected.
Explanation
The closure provided only runs when the binding is being resolved. That's why it's a closure, it can be saved in the service container and resolved at any time while the program runs.
Solution
To see the resolved binding, create a controller and resolve the class in that controller:
// File: app/Http/Controllers/TestController.php
namespace App\Http\Controllers;
// This isn't the best way, but it works. See the best way below
class TestController extends Controller {
public function index()
{
return \App::make('Test')->helloWorld();
}
}
Of course, don't forget to register the route:
// File: routes/web.php
Route::get('/', 'TestController#index');
The binding will resolve when you hit the homepage.
However, as I said, it's not the best way, so here I prepared a better way. Change the way you register the binding:
// File: app/Providers/TestProvider.php
namespace App\TestProvider;
use Illuminate\Support\ServiceProvider;
use App\TestProvider\Test;
// Better way
class TestServiceProvider extends ServiceProvider
{
/**
* Register bindings in the container.
*
* #return void
*/
public function register()
{
// Note: we bind the exact complete class name!
$this->app->bind(Test::class, function ($app) {
return new Test();
});
}
}
After this change the controller so that it looks like this:
namespace App\Http\Controllers;
use App\TestProvider\Test;
class TestController extends Controller {
/**
* #var Test $test
*/
private $test;
// Let Laravel resolve the dependency on constructing the class
public function __construct(Test $test)
{
$this->test = $test;
}
public function index()
{
return $this->test->helloWorld();
}
}
You will see that the exact same thing happens, but it looks more elegant and avoids conflicts.
Details
Laravel gives only a high level overview of the service container, which doesn't help to learn how it works on the inside. The best way to see that is to go down the call stack.
When you do that, you find that Laravel registers every class in the project in the service container. That means that whether you create a service provider or not, the class will be in the container. How exactly?
When you run php artisan optimize, Laravel creates files that have array with all the classes of the project. When you run the app, after registering everything from the service providers, Laravel registers the rest of the classes from that file.
That means that in your case, if you don't specifically register the Test class, it will still be resolvable. Basically, you only need to register classes that need some specific instructions to be resolved.
So how does Laravel resolve the dependencies?
When you run \App::make(Test::class) or inject dependency via type hinting in the constructor (the "better way" from my solution), Laravel looks for that dependency among the bindings.
When it finds the dependency, it resolves either the closure associated to it or the constructor of the class directly.
When it resolves the constructor directly, it looks for type hints among the constructor parameters and recursively resolves all of them until there's nothing else to resolve.
After that it returns the resolved class.
Of course, bear in mind that for Laravel to analyze the contructor of a class, it needs to be resolved via the service container in the first place. You can't just call $test = new Test(); and expect Laravel to do all the magic :)
Conclusion
This is a rather quick overview of Laravel's service container. The best way for you to learn it is, of course, studying the sources for yourself. It's truly elegant and it uses PHP's functionality to the fullest.
I really hope this shed some light on the service container for you and can help you in the future :)
The closure passed to the bind() method is not executed until you actually attempt to resolve the alias you are binding.
So, if you dd('breaker') inside the closure, this won't actually get executed until Test is resolved (whatever your preferred resolution method is):
Service provider:
// bind the closure to the 'Test' alias
public function register()
{
$this->app->bind('Test', function ($app) {
dd("BREAKER");
return new Test();
});
}
Code that resolve Test alias:
// different ways of resolving the alias out of the container.
// any of these will execute the bound closure.
$test = resolve('Test');
$test = app('Test');
$test = app()->make('Test');
$test = \App::make('Test');
try:
$this->app->bind(Test::class, function ($app) {
return new Test();
});