I'am a Brazilian developer, so... sorry for my limited English right away.
Well, in fact my problem is more a convention problem because until now I hadn't use services with Laravel (my apps were that simple so far).
I read about it before ask this question, but nothing helped with this specific situation. I'll try to describe in a objective way.
before that, just a comment: I know about the mistake using just controllers in these example. The ask is really about that mistake.
Well, the actual structure is:
abstract class CRUDController extends Controller {
protected function __construct($data, $validatorData) {
// store the data in a attribute
// create with Validator facade the validation and store too
}
abstract protected function createRecord();
protected function create() {
try {
// do the validation and return an Response instance with error messages
// if the data is ok, store in the database with models
// (here's where the magic takes place) in that store!
// to do that, calls the method createRecord (which is abstract)
$this->createRecord();
// return a success message in an Response instance
}
catch(\Exception $e) {
// return an Response instance with error messages
}
}
}
class UserController extends CRUDController {
public function __construct($data) {
parent::__construct($data, [
'rules' => [
// specific user code here
],
'messages' => [
// specific user code here
],
'customAttributes' => [
// specific user code here
]
]);
}
protected function createRecord() {
$user = new UserModel();
// store values here...
$user->save();
return $user;
}
}
// here's the route to consider in that example
Route::post('/user', 'WebsiteController#register');
class WebsiteController extends Controller {
private $request;
public function __construct(Request $request) {
$this->request = $request;
}
public function register() {
$user = new UserController();
$user->create($this->request);
// here's the problem: controller working with another controller
}
}
class UserAPIController extends Controller {
// use here the UserController too
}
and many other classes that extends CRUDController in the same way...
What I want
I want to create a controller (called here as CRUDController) to reuse methods like the pattern says (create, read, update and delete).
To be really objective here I'll use the create method as an example.
With the code above it seems clear the purpose? I think so... all my controllers have that code of validation equal and reusable. That's the thing.
Besides that, I want to my route of website call another controller (UserController) to store new users... but in the same way, I'll create an API that uses the same controller in the same way (with validations etc). That's the purpose of Responses in the CRUDController (I'll read them in the WebSiteController to resolve what to do, like show a view and in the other hand with the API I'll basically return the Response.
My real problem
Convention and pattern. The MVC pattern is broken here. Controller calling another controller is wrong and I know that.
I want to know what thing I should use! Services? Is that right? I see a lot (really) of examples of services but nothing like that, working with models and reusing code, etc. I never use Services but I know how to use, but I don't know if it's right to these cases.
I really hope that someone can help here and sorry once again for the mistakes with the English. Thanks a lot.
You're calling the CRUD controller a controller but it does not behave as an MVC controller. At best it's just a helper class. You could always do this:
abstract class CRUDManager {
//As you had the CRUDController
}
class UserManager extends CRUDManager {
//As you had the UserController
}
In your AppServiceProvider:
public function boot() {
$app->bind(UserManager::class, function ($app) {
return new UserManager(request()->all()); //I guess that's what you need.
});
}
Whenever you need to use it you can do:
public function register(UserManager $user) {
$user->create();
}
Now one thing to point out. It's not a good idea to initialise the request in the constructor. You should use dependency injection in controller methods. I don't even know if the request is available when the controller is being constructed (I know the session is not). The reason why I say this is that the middleware runs after the controller is constructed and therefore the request may be modified when the controller method is called.
Another note: If you did the original solution because you needed to use certain controller methods, then you can just use the corresponding traits (because the controller itself does not really have many method). I'm guessing a trait like ValidatesRequests would be one you'd need to use.
I'll answer my own question. I use a pattern called Repository Pattern to resolve the problem (or I try to use, because it's the first time using this pattern: maybe I don't use in the right way in every steps).
Files structure
Controllers
UserController.php
Models
UserModel.php
Providers
UserRepositoryServiceProvider.php
Repositories
RepositoryInterface.php
Repository.php
User
UserRepositoryInterface.php
UserRepository.php
Traits
InternalResponse.php
With that structure I did what I wanted in my question without working just with controllers.
I create a trait called InternalResponse. That trait contains a few methods that receive a transaction, validate if it's the case and then return a Response (called "internal" in my logic because the controller will read and maybe change the Response before return it in the end).
The Repository class, which is abstract (because another class must extend it to make sense to use. In this case the class UserRepository will extend...), uses the Trait mentioned.
Well, with it in mind, it's possible to know that the UserController uses the UserRepositoryInterface, that provides an object UserRepository: because the UserRepositoryServiceProvider register this with that interface.
I think there's no need to write code here to explain, because the problem is about an pattern, and these words explain well the problem (in the question) and the resolution with this answer here.
I'll write here a conclusion, I mean, the files structure with comments to explain a little bit more, to end the answer.
Conclusion: Files structure with comments
Controllers
UserController.php
// the controller uses dependency injection and call methods of
// UserRepository, read and changes the Response receveid to finally
// create the final Response, like returning a view or the response
// itself (in the case it's an API controller)
Models
UserModel.php
// an normal model
Providers
UserRepositoryServiceProvider.php
// register the UserRepositoryInterface to
// return a UserRepository object
Repositories
RepositoryInterface.php
// the main interface for the Repository
Repository.php
// the main repository. It's an abstract class.
// All the others repositories must extend that class, because
// there's no reason to use a class Repository without an Model
// to access the database... That class share methods like create,
// read, update and delete, and the methods validate and transaction
// too because uses the trait InternalResponse.
User
UserRepositoryInterface.php
// the interface for UserRepository class
UserRepository.php
// that class extend Repository and uses the UserModel
Traits
InternalResponse.php
// trait with methods like validate and transaction. the method
// validate, read and validate the data receveid for the methods
// create and update. and all the CRUD methods uses the method
// transaction to perform the data to the database and return a
// response of that action.
That's what I do and like I said before, I don't know if it's a hundred percent correct in reference to Repository Pattern.
I hope this can help someone else too.
Thanks for all.
Related
I am trying to use a trait as a typehint for my Laravel resource controllers.
The controller method:
public function store(CreateCommentRequest $request, Commentable $commentable)
In which the Commentable is the trait typehint which my Eloquent models use.
The Commentable trait looks like this:
namespace App\Models\Morphs;
use App\Comment;
trait Commentable
{
/**
* Get the model's comments.
*
* #return \Illuminate\Database\Eloquent\Relations\MorphMany
*/
public function Comments()
{
return $this->morphMany(Comment::class, 'commentable')->orderBy('created_at', 'DESC');
}
}
In my routing, I have:
Route::resource('order.comment', 'CommentController')
Route::resource('fulfillments.comment', 'CommentController')
Both orders and fulfillments can have comments and so they use the same controller since the code would be the same.
However, when I post to order/{order}/comment, I get the following error:
Illuminate\Contracts\Container\BindingResolutionException
Target [App\Models\Morphs\Commentable] is not instantiable.
Is this possible at all?
So you want to avoid duplicate code for both order and fulfillment resource controllers and be a bit DRY. Good.
Traits cannot be typehinted
As Matthew stated, you can't typehint traits and that's the reason you're getting the binding resolution error. Other than that, even if it was typehintable, the container would be confused which model it should instantiate as there are two Commentable models available. But, we'll get to it later.
Interfaces alongside traits
It's often a good practice to have an interface to accompany a trait. Besides the fact that interfaces can be typehinted, you're adhering to the Interface Segregation principle which, "if needed", is a good practice.
interface Commentable
{
public function comments();
}
class Order extends Model implements Commentable
{
use Commentable;
// ...
}
Now that it's typehintable. Let's get to the container confusion issue.
Contexual binding
Laravel's container supports contextual binding. That's the ability to explicitly tell it when and how to resolve an abstract to a concrete.
The only distinguishing factor you got for your controllers, is the route. We need to build upon that. Something along the lines of:
# AppServiceProvider::register()
$this->app
->when(CommentController::class)
->needs(Commentable::class)
->give(function ($container, $params) {
// Since you're probably utilizing Laravel's route model binding,
// we need to resolve the model associated with the passed ID using
// the `findOrFail`, instead of just newing up an empty instance.
// Assuming this route pattern: "order|fullfilment/{id}/comment/{id}"
$id = (int) $this->app->request->segment(2);
return $this->app->request->segment(1) === 'order'
? Order::findOrFail($id)
: Fulfillment::findOrFail($id);
});
You're basically telling the container when the CommentController requires a Commentable instance, first check out the route and then instantiate the correct commentable model.
Non-contextual binding will do as well:
# AppServiceProvider::register()
$this->app->bind(Commentable::class, function ($container, $params) {
$id = (int) $this->app->request->segment(2);
return $this->app->request->segment(1) === 'order'
? Order::findOrFail($id)
: Fulfillment::findOrFail($id);
});
Wrong tool
We've just eliminated duplicate controller code by introducing unnecessary complexity which is as worse as that. ๐
Even though it works, it's complex, not maintainable, non-generic and worst of all, dependent to the URL. It's using the wrong tool for the job and is plain wrong.
Inheritance
The right tool to eliminate these kinda problems is simply inheritance. Introduce an abstract base comment controller class and extend two shallow ones from it.
# App\Http\Controllers\CommentController
abstract class CommentController extends Controller
{
public function store(CreateCommentRequest $request, Commentable $commentable) {
// ...
}
// All other common methods here...
}
# App\Http\Controllers\OrderCommentController
class OrderCommentController extends CommentController
{
public function store(CreateCommentRequest $request, Order $commentable) {
return parent::store($commentable);
}
}
# App\Http\Controllers\FulfillmentCommentController
class FulfillmentCommentController extends CommentController
{
public function store(CreateCommentRequest $request, Fulfillment $commentable) {
return parent::store($commentable);
}
}
# Routes
Route::resource('order.comment', 'OrderCommentController');
Route::resource('fulfillments.comment', 'FulfillCommentController');
Simple, flexible and maintainable.
Arrrgh, wrong language
Not so fast:
Declaration of OrderCommentController::store(CreateCommentRequest $request, Order $commentable) should be compatible with CommentController::store(CreateCommentRequest $request, Commentable $commentable).
Even though overriding method parameters works in the constructors just fine, it simply does not for other methods! Constructors are special cases.
We could just drop the typehints in both parent and child classes and go on with our lives with plain IDs. But in that case, as Laravel's implicit model binding only works with typehints, there won't be any automatic model loading for our controllers.
Ok, maybe in a better world.
๐Update: See PHP 7.4's support for type variance ๐
Explicit route model binding
So what we gonna do?
If we explicitly tell the router how to load our Commentable models, we can just use the lone CommentController class. Laravel's explicit model binding works by mapping route placeholders (e.g. {order}) to model classes or custom resolution logics. So, while we're using our single CommentController we can utilize separate models or resolution logics for orders and fulfillments based on their route placeholders. So, we drop the typehint and rely on the placeholder.
For resource controllers, the placeholder name depends on the first parameter you pass to the Route::resource method. Just do a artisan route:list to find out.
Ok, let's do it:
# App\Providers\RouteServiceProvider::boot()
public function boot()
{
// Map `{order}` route placeholder to the \App\Order model
$this->app->router->model('order', \App\Order::class);
// Map `{fulfillment}` to the \App\Fulfilment model
$this->app->router->model('fulfillment', \App\Fulfilment::class);
parent::boot();
}
Your controller code would be:
# App\Http\Controllers\CommentController
class CommentController extends Controller
{
// Note that we have dropped the typehint here:
public function store(CreateCommentRequest $request, $commentable) {
// $commentable is either an \App\Order or a \App\Fulfillment
}
// Drop the typehint from other methods as well.
}
And the route definitions remain the same.
It's better than the first solution, as it does not rely on the URL segments which are prone to change contrary to the route placeholders which rarely change. It's also generic as all {order}s will be resolved to \App\Order model and all {fulfillment}s to the App\Fulfillment.
We could alter the first solution to utilize route parameters instead of URL segments. But there's no reason to do it manually when Laravel has provided it to us.
Yeah, I know, I don't feel good, too.
You can't typehint traits.
However, you can typehint interfaces. So you can create an interface that requires the methods from the trait and resolve that. Then have your classes implement that interface and you should be OK.
EDIT: As #Stefan has kindly pointed out, it's still likely to be difficult to resolve the interface to a concrete class because it will need to resolve to different classes under different circumstances. You could access the request in the service provider and use the path to determine how to resolve it, but I'm a bit dubious of that. I think putting them in separate controllers and using inheritance/traits to share common functionality may be a better bet, since the methods in each controller can type hint the required object, and then pass them to the equivalent parent method.
For my case I have following resources:
Route::resource('books/storybooks', 'BookController');
Route::resource('books/magazines', 'BookController');
After php artisan route:cache and it creates the route to tie up with 'magazine' model.
The solution is to add following line in app/Providers/RouteServiceProvider.php > boot() method, after parent::boot():
Route::model('magazine', \App\Book::class);
Pay attention to the singular and plural.
I have an application where I have to deal with multiple vendors - each having their different implementation. For example, let's say Payment Systems, there are many vendors and banks.
There are a few things common, like implementation process. In each case, I have to give a callback URL to them to give me a response.
For now, I have two vendors - VendorPay and VendorA.
I will have two routes:
payment/callback/vendorpay
payment/callback/vendora
each of them call two methods in controller.
processVendorpay and processVendora
Now, if I want to add, lets say, 15 more vendors like this, will I have to create methods everytime I add new vendor? Is there any cleaner solution for this?
My controller right now looks like this:
class PaymentController extends BaseController
{
protected $vendorpay_validator, $vendora_validator, $transaction, $transaction_log, $vendor_product, $vendor_transaction;
public function __construct(VendorpayValidator $vendorpay_validator, VendorAValidator $vendora_validator, Transaction $transaction, TransactionLog $transaction_log, VendorProduct $vendor_product, VendorTransaction $vendor_transaction)
{
$this->vendorpay_validator = $vendorpay_validator;
$this->vendora_validator = $vendora_validator;
$this->transaction = $transaction;
$this->transaction_log = $transaction_log;
$this->vendor_product = $vendor_product;
$this->vendor_transaction = $vendor_transaction;
}
}
These four are the Model Repository Objects: $transaction, $transaction_log, $vendor_product, $vendor_transaction
If I have to add more venodrs, it keeps on adding validator object here. What would be a much cleaner way to do it?
One of the solutions that I thought was - for multiple routes, I just create one method. Now I'll check the route in this method and call the Factory Object basis on that.
You should have just one route...
payment/callback/{vendor}
Then if you want to go the factory route (which I think would be a good idea in this case)...
class VendorValidatorFactory
{
private function __construct() {}
public static function getValidator($vendor)
{
switch ($vendor) {
case 'vendorpay':
return new VendorPayValidator;
case 'vendora':
return new VendarAValidator;
}
}
}
Remove the now unnecessary injections from your constructor and in the method which responds to your route, use the factory to grab the correct validator...
class SomeController extends Controller
{
public function __construct(Transaction $transaction, TransactionLog $transaction_log, VendorProduct $vendor_product, VendorTransaction $vendor_transaction)
{
$this->transaction = $transaction;
$this->transaction_log = $transaction_log;
$this->vendor_product = $vendor_product;
$this->vendor_transaction = $vendor_transaction;
}
public function processVendorResponse($vendor)
{
$validator = VendorValidatorFactory::getValidator($vendor);
}
}
And just a suggestion, every time you need to add a new method to your validator classes which your controller uses, add that to a ValidatorInterface and make sure all your validators implement that ValidatorInterface. This way when you need to add more, all you need to do is implement that interface and that should tell you exactly what functions you need to write. Then just update your factory method to include the new one and you are done. No more changing your controller, adding routes, or adding dependencies to your controller.
I am currently facing a very interesting dilemma with my architecture and implementation.
I have an interface called ServiceInterface which have a method called execute()
Then I have two different implementations for this interface: Service1 and Service2, which implements the execute method properly.
I have a controller called MainController and this controller has a "type-hint" for the ServiceInterface (dependency injection), it means that both, Service1 and Service2, can be called as resolution for that dependency injection.
Now the fun part:
I do not know which of those implementations to use (Service1 or Service2) because I just know if I can use one or other based on a user input from a previous step.
It means the user choose a service and based on that value I know if a can use Service1 or Service2.
I am currently solving the dependency injection using a session value, so depending of the value I return an instance or other, BUT I really think that it is not a good way to do it.
Please, let me know if you faced something similar and, how do you solve it, or what can I do to achieve this in the right way.
Thanks in advance. Please let me know if further information is required.
Finally, after some days of researching and thinking a lot about the best approach for this, using Laravel, I finally solved it.
I have to say that this was especially difficult in Laravel 5.2 because, in this version, the Session middleware only is executed in the controllers used in a route, it means that if for some reason I used a controller (not linked for a rote) and try to get access to the session it is not going to be possible.
So, because I cannot use the session, I decided to use URL parameters. Here you have the solution approach; I hope some of you found it useful.
so, you have an interface:
interface Service
{
public function execute();
}
Then a couple of implementations for the interface:
Service one:
class ServiceOne implements Service
{
public function execute()
{
.......
}
}
Service two.
class ServiceTwo implements Service
{
public function execute()
{
.......
}
}
The interesting part is that I have a controller with a function with a dependency with the Service interface. Still, I need to resolve it dynamically to ServiceOne or ServiceTwo based on user input. So:
The controller
class MyController extends Controller
{
public function index(Service $service, ServiceRequest $request)
{
$service->execute();
.......
}
}
Please note that ServiceRequest, validated that the request already have the parameter that we need to resolve the dependency (call it 'service_name')
Now, in the AppServiceProvider we can resolve the dependency in this way:
class AppServiceProvider extends ServiceProvider
{
public function boot()
{
}
public function register()
{
//This specific dependency is going to be resolved only if
//the request has the service_name field stablished
if(Request::has('service_name'))
{
//Obtaining the name of the service to be used (class name)
$className = $this->resolveClassName(Request::get('service_name')));
$this->app->bind('Including\The\Namespace\For\Service', $className);
}
}
protected function resolveClassName($className)
{
$resolver = new Resolver($className);
$className = $resolver->resolveDependencyName();
return $className;
}
}
So now all the responsibility is for the Resolver class. This class basically use the parameter passed to the constructor to return the full name (with namespace) of the class that is going to be used as an implementation of the Service interface:
class Resolver
{
protected $name;
public function __construct($className)
{
$this->name = $className;
}
public function resolveDependencyName()
{
//This is just an example, you can use whatever as 'service_one'
if($this->name === 'service_one')
{
return Full\Namespace\For\Class\Implementation\ServiceOne::class;
}
if($this->name === 'service_two')
{
return Full\Namespace\For\Class\Implementation\ServiceTwo::class;
}
//If none, so throw an exception because the dependency can not be resolved
throw new ResolverException;
}
}
Well, I really hope it helps some of you.
Best wishes!
---------- EDIT -----------
I just realize that it is not a good idea to use the request data directly inside the container of Laravel. It really is going to cause some trouble in the long term.
The best way is to directly register all the possible instances supported (serviceone and servicetwo) and then resolve one of them directly from a controller or a middleware, so then is the controller "who decides" what service to use (from all the available) based on the input from the request.
In the end, it works at the same, but it is going to allow you to work more naturally.
I have to say thanks to rizqi, a user from the questions channel of the slack chat of Laravel.
He personally created a golden article about this. Please read it because it solves this issue completely and in a very right way.
laravel registry pattern
The fact that you define that your controller works with ServiceInterface is ok
If you have to choose the concrete implementation of the service basing on a previous step (that, as i've understood, happens in a previous request) storing the value in session or in database is right too, as you have no alternative: to choose the implementation you have to know the value of the input
The important point is to 'isolate' the resolution of the concrete implementation from the input value in one place: for example create a method that takes this value as a parameter and returns the concrete implementation of the service from the value:
public function getServiceImplementation($input_val)
{
switch($input_val)
{
case 1 : return new Service1();
case 2 : return new Service2();
}
}
and in your controller:
public function controllerMethod()
{
//create and assign the service implementation
$this->service = ( new ServiceChooser() )->getServiceImplementation( Session::get('input_val') );
}
In this example i've used a different class to store the method, but you can place the method in the controller or use a Simple Factory pattern, depending on where the service should be resolved in your application
It's an interesting problem. I'm currently using Laravel 5.5 and have been mulling it over. I also want my service provider to return a specific class (implementing an interface) based upon user input. I think it's better to manually pass the input from the controller so it's easier to see what's going on. I would also store the possible values of the class names in the config.
So based upon the Service classes and interface you've defined above i came up with this:
/config/services.php
return [
'classes': [
'service1' => 'Service1',
'service2' => 'Service2',
]
]
/app/Http/Controllers/MainController.php
public function index(ServiceRequest $request)
{
$service = app()->makeWith(ServiceInterface::class, ['service'=>$request->get('service)]);
// ... do something with your service
}
/app/Http/Requests/ServiceRequest.php
public function rules(): array
$availableServices = array_keys(config('services.classes'));
return [
'service' => [
'required',
Rule::in($availableServices)
]
];
}
/app/Providers/CustomServiceProvider.php
class CustomServiceProvider extends ServiceProvider
{
public function boot() {}
public function register()
{
// Parameters are passed from the controller action
$this->app->bind(
ServiceInterface::class,
function($app, $parameters) {
$serviceConfigKey = $parameters['service'];
$className = '\\App\\Services\\' . config('services.classes.' . $serviceConfigKey);
return new $className;
}
);
}
}
This way we can validate the input to ensure we are passing a valid service, then the controller handles passing the input from the Request object into the ServiceProvider. I just think when it comes to maintaining this code it will be clear what is going on as opposed to using the request object directly in the ServiceProvider.
PS Remember to register the CustomServiceProvider!
I find the best way to deal with this is using a factory pattern. You can create a class say ServiceFactory and it has a single method create() it can accept an argument which is used to dynamically choose which concrete class to instantiate.
It has a case statement based on the argument.
It will use App::make(ServiceOne::class) or App::make(ServiceTwo::class).depending on which one is required.
You are then able to inject this into your controller (or service which depends on the factory).
You can then mock it in a service unit test.
Recently, I had to implement a similar logic where I was to implement a method to perform mobile top-ups for multiple networks in our application. So, I decided to implement the logic using Factory and Bridge pattern. Factory to create an instance of the concrete Service class based on the user input, and then, the Bridge pattern to set closely related classes into separate hierarchies and route the request to the respective class.
In the controller's method, both Factory and Service classes are injected. The TopUpServiceFactory's create method creates an object of the concrete class. The TopUpService class then routes the request to that concrete class method.
class TopUpController extends Controller
{
public function topUp(Request $request, TopUpServiceFactoryInterface $serviceFactory, TopUpServiceInterface $topUpService)
{
$serviceFactory->create($request->networkCode);
$topUpService->TopUp($request->all());
}
}
The TopUpServiceFactoryInterface and TopUpServiceInterface are bound to TopUpServiceFactory and TopUpService concrete Classes respectively in Service Container.
class AppServiceProvider extends ServiceProvider
{
public function register()
{
$this->app->bind(TopUpServiceFactoryInterface::class, TopUpServiceFactory::class);
$this->app->bind(TopUpServiceInterface::class, TopUpService::class);
}
}
The create method accepts user input and creates an object of the respective class based on the user input.
class TopUpServiceFactory implements TopUpServiceFactoryInterface
{
public function create(string $networkCode)
{
switch ($networkCode) {
case 'network1':
app()->bind(NetworkServiceInterface::class, Network1Service::class);
break;
case 'network2':
app()->bind(NetworkServiceInterface::class, Network2Service::class);
break;
default:
app()->bind(NetworkServiceInterface::class, DefaultNetworkService::class);
break;
}
}
}
The Service Class then picks the object of NetworkService Class and forwards the request.
class TopUpService implements TopUpServiceInterface
{
public function topUp(array $requestParams)
{
$networkService = app()->get(NetworkServiceInterface::class);
$networkService->topUp($requestParams);
}
}
All network's concrete classes implement a common interface NetworkServiceInterface, which is used to inject dependency dynamically, implementing Liskov Substitution Principle
class Network1Service implements NetworkServiceInterface
{
public function topUp(array $requestParam)
{
Process Topup ......
}
}
class Network2Service implements NetworkServiceInterface
{
public function topUp(array $requestParam)
{
Process Topup ......
}
}
...
I'm building a simple MVC framework in PHP and I'm stuck at the part where I have to create a BaseController class.
Every "page" controller needs to extend from this BaseController. Because this BaseController class will have properties that will give the user access to a template engine and a Logger class (and some other things).
The problem I have is that I'm not sure how to instantiate those things in the BaseController class. I can obviously hard code it in the __constructo() like this:
class BaseController
{
protected $view;
protected $log;
public function __construct()
{
$this->view = new \namespace\view('param1', 'param2');
$this->log = new Logger('name');
$this->log->pushHandler(new StreamHandler('path/to/your.log', Logger::WARNING));
}
}
But this doesn't make it very modular. It makes it hard to change the Logger class for example. Or if the user wants to change the template engine to Smarty for example.
I also can't really use a form of Dependancy Injection. Because then every controller that extends from the BaseController will have to pass those instances to the BaseController.
That would look something like this:
class BaseController
{
protected $view;
protected $log;
public function __construct($view, $log)
{
$this->view = $view;
$this->log = $log;
}
}
HomeController
class HomeController extends BaseController
{
public function __construct($view, $log)
{
parent::__construct($view, $log);
// Do my own stuff
}
}
To me that's not really user friendly when a user only wants to do a simple thing in the __constructor. Not even with an IoC.
So the only thing that I can think of now is to use a Service Provider from the __construct method in the BaseController. But I'm not really sure if that's the way to go? Maybe there is a better alternative?
So what would be a good solution to solve this problem?
PS. And if I do need a Service Locator, are there any good examples out there? The ones I've found were written by people that seemed like they didn't really know what they were talking about. They were basically copying each others blog posts.
You first need to think what's a controllers responsibility, why would it need access to logging functionality or why would it be setting the template engine or switching templates?
The controllers job is simply to extract the data from the request(mostly form data/user input) and sending it to the model layer via a service, it should not be selecting templates, that's the views job.
You obviously want you keep the dependencies of your base controller to a minimum so that when instantiating child controllers you don't have a big list of dependencies to inject.
My base controller has two dependencies, the request object and a view which are both injected in. Controllers are simple and light, no logic or anything fancy should happen in them. Once ever I had to use a logger in one of my controllers but that was just because PayPal was sending a request to it using the IPN system and I needed to log all the data in the request to a file to see what was going on, other than special cases like that I can't see why a controller would need a logger. In this case only the controller which dealt with the PayPal request held an instance of a logger, not the parent base controller.
You should always inject your dependencies. Don't instantiate objects in constructors, it makes your class tightly coupled to those objects.
If you end up using a service locator it can be a sign that your classes break the single responsibility principle of OOP.
Controllers are meant to be simple, don't over complicate them by adding in dependencies you think they might need in the future, especially not to the base controller or you may have a lot of refactoring to do.
I am working on building a lightweight MVC, mainly for the learning process but I would like it to be good enough to use eventually.
Below is a basic example/demo of how a basic controller might would look, let's assume the URI has been processed and routed to this controller and these 2 methods.
1) I need to get data from database/cache/etc... inside my Model classes, I just need help on how I should load my models into my example controller below, you can see that I have added this below $profileData = $this->model->getProfile($userId) that is just made up and does not exist's, how could I get something like that to work though? Or should I load the model into the class a different way?
2) A lot of pages will require a user to be logged into the site. SHould I process that part below in the controller to check if a user is logged in, example, before building the profile page, check if user is logged in, if not then build a login page instead and add these checks inside of each controller method/page?
/**
* Example Controller
*/
class User_Controller extends Core_Controller {
// domain.com/user/id-53463463
function profile($userId)
{
//GET data from a Model
$profileData = $this->model->getProfile($userId);
$this->view->load('userProfile', $profileData);
}
// domain.com/user/friends/
function friends()
{
//GET data from a Model
$friendsData = $this->model->getFriendlist();
$this->view->load('userFriends', $friendsData);
}
}
core
abstract class Core_Controller {
protected $view;
protected $model;
function __construct(DependencyContainer $dependencyContainer){
$this->view = new Core_View();
//$this->view = $dependencyContainer->get(view);
}
}
There are probably tons of ways to accomplish what you are trying.
The "easiest" is probably to just override the constructor and instantiate the model directly.
in User_Controller:
public function __construct(DependencyContainer $dc) {
parent::__construct($dc);
$this->model = new User_Model();
}
I'm guessing that you are looking for something a little more automated though. If you want the Model to have the same name as the controller minus "_Controller", just use get_class($this) in the constructor and use PHP's string functions to parse out what you want. Once you have that in a variable, you can use that variable to instantiate the model:
in Core_Controller:
public function __construct(DependencyContainer $dc) {
$this->view = new Core_View();
// $model_class should be 'User_Model' now
$model_class = str_replace('_Controller', '_Model', get_class($this));
// now instantiate the model
$this->model = new $model_class();
}
I haven't actually worked with any framework that can only have one model associated with each controller (except may CakePHP? I can't remember). With Symfony, the models and controllers are completely decoupled so you can use any model with any controller. You just instantiate the model as need. Symfony use the Doctrine ORM so for example, in a controller action, if you needed a model you would do something like this:
$model = Doctrine::getTable('User');
It might be worthwhile to consider a design more like that in order to promote a decoupled design and I promise that you will want more than one model in some controller at some point.
2.) As far as authentication. Something that seems to be fairly common is to have some sort of setting (whether in a config file or a member variable) that says whether or not the current action needs the user to be authenticated. This is processed each time the action runs (Yii calls these kinds of things filters). If the user needs to be logged in, it stores the page that they are trying to access, and then redirects them to a log in page (you should only ever have to create one). Once they properly authenticate, it will redirect them back to where they were originally heading.