I have a question about using Trait and Interfaces in PHP.
A trait with foobar function
<?php
trait FoobarTrait
{
protected $foobar;
public function setFoobar($foobar)
{
$this->foobar = $foobar
}
public function getFoobar()
{
return $this->foobar;
}
}
The specific Interface to specify how to use Trait
<?php
interface FoobarInterface
{
public function setFoobar($foobar);
public function getFoobar();
}
I want use foobar feature in a class. What is the best way ?
It is necessary to implements with an interface and specify trait or it is an induced behavior ?
<?php
class FoobarClass implements FoobarInterface
{
use FoobarTrait;
}
Or this
<?php
class FoobarClass
{
use FoobarTrait;
}
Thank's for your reply and debate ;)
As it was correctly stated in the comments by #Federkun, "it depends". In my opinion mostly on how are you about to use your FoobarClass.
If it's an implementation of some kind of service that can have multiple implementations depending on external conditions (consider file system or S3 for handling user uploads, as an example), I would use FooBarInterface as I can then type-hint it in other places using the service.
If you wish to just avoid repeating yourself, you could use a trait and no interfaces. Or even a base abstract class AbstractFooBar { ... } to encapsulate the repeating code.
If you only have one implementation for getting and setting $fooBar - just put it all in the same class :)
Related
I am currently on PHPUnit v5.7.27
I would like to create a mock object that uses an array of traits. How would I go about this? I only see getMockForTrait as a way to create a mock object using a single trait. My issue is that the trait requires the existence of another trait at the class level.
Update: More context to the issue
Given:
trait GetSet {
public function __call(){ /* does some magic */
}
trait RepositoryAware {
public function getRepository(string $name)
{
/* makes use of the GetSetTrait*/
}
}
class Controller
{
use GetSet;
use RepositoryAware;
}
Given the limitations of PHP, I can not simply put a use GetSet on the RepositoryAware trait because other traits that the controller imports could also bring the GetSet trait. Furhtermore, the controller class itself could be using the behavior provided by the GetSet trait.
The current solution I have is to create a Dummy Class that imports both traits and mock that class instead:
class RepositoryAwareClass
{
use GetSet;
use RepositoryAware;
}
Like this I am able to properly test the behavior provided by the RepositoryAware trait while at the same time composing its requirement of the GetSet trait.
Mocking concept was built with the idea that you would be using dependency injection. I can certainly see why you may not want to use dependency injection with this multiple inheritance like model that php uses called "Traits". Mocking tools like the one built for phpunit was built to substitute instances of objects not classes/interfaces/traits themselves. PHP Traits are more like having a static dependency instead of a dependency on an instance of an object. However, even if you were using traits and assuming a trait was basically the same as a class, according to mocking best practices should test the trait as its own test instead of testing a trait through another class. If you want to mock the trait itself you may want to try to revisit your design as I do not believe it can be done. You can certainly mock a trait and test that trait but you cannot mock a trait and then inject it as a dependency on an object. Imagine that a class for example implements an interface, mocking a trait would be the same a mocking an interface that a class implements, its not possible. You can only mock an interface of an object that a class depends upon through setter or constructor based dependency injection. Another example would be to try and mock the class that the class under test inherits from. You can't do that either. Perhaps in the javascript world this type of thing could be useful and from some people's point of view desired, but I think if you want to use mocking you would need to stick with object dependency injection instead of static use of traits.
So what's the alternative? I think the following example would be how to use perhaps "traditional" OOP practices with mocking to achieve your goal of sharing functionality without using inheritance. The example also makes your dependencies more explicit. And for the record, I applaud you for NOT using inheritance.
<?php
interface GetterSetter {
public function __call();
}
interface RepositoryProvider {
public function getRepository(string $name);
}
class GetSet implements GetterSetter {
public function __call() {
/* does some magic */
}
}
class DefaultRepository implements RepositoryProvider, GetterSetter {
/**
* #var GetterSetter
*/
private $_getterSetter;
public function __construct(GetterSetter $getterSetter) {
$this->_getterSetter = $getterSetter;
}
public function getRepository(string $name) {
// makes use of the GetSetTrait
$this->__call();
}
public function __call() {
// makes use of the GetSetTrait
$this->_getterSetter->__call();
}
}
class Controller implements RepositoryProvider, GetterSetter {
/**
* #var RepositoryProvider
*/
private $repositoryProvider;
public function __construct() {
$this->repositoryProvider = new DefaultRepository(new GetSet());
}
public function getRepository(string $name) {
return $this->repositoryProvider->getRepository($name);
}
public function __call() {
$this->repositoryProvider->__call();
}
}
In general I feel like the PHP community took a wild left turn, trying to be more like javascript and I feel that traits can walk you into a corner. This is a very good example of such a corner. I would really avoid them, at least for now. In the long run I believe Generics would be the better solution to your problem of needing a generic GetSet piece of code but generics haven't been implemented in php yet :-(.
I currently have an abstract class which i am extending to other controllers. I have a abstract function within the abstract class which takes the value and places it in the __construct.
abstract class Controller extends BaseController {
abstract public function something();
public function __construct(Request $request) {
if (!is_null($this->something())){
$this->global_constructor_usse = $this->something();
}
}
}
My problem is that, on controllers that don't require this abstract function, I am having to place in the empty function.
class ControllerExample extends Controller {
public function something(){
return 'somethinghere';
}
}
Is there anyway to making the abstract function optional, or have a default value?
class EmptyControllerExample extends Controller {
public function something(){}
}
It is not possible to have a abstract method optional, as it is implied in PHP that all abstract methods must have an implementation.
There are legit use cases for optional abstract methods, yes: event handlers, metadata describers, etc. Unfortunately, you'll need to use regular, non-abstract methods with an empty body, and indicate in PHPDoc that they will do nothing unless extended.
Be wary, though: this can very quickly turn into code smell by diffusing a class responsability with their children. If you're dealing with generic events, you can look into Laravel's own event system, or the Observer pattern instead.
Abstract functions in a parent class, should only be used if its required by your application to implement the following method in all controllers who inherits from it, clearly it is not the case.
In this case i would make a trait. Here you create a trait which can be implemented by the classes who needs it. Notice the use keyword usage, use somethingTrait;
trait SomethingTrait
{
public function something()
{
echo "something called";
}
}
class Controller
{
use SomethingTrait;
public function run()
{
$this->something();
}
}
phpfiddle link
Another aproach could be doing a class inheritance structure, if the controllers you want to implement the methods has something in common. Where you would implement your special method in CrmController, where you still would be able to create shared methods in the abstract controller.
AbstractController
|
CrmController
|
CompanyController
For your question, 'Is there anyway to making the abstract function optional or have a default value?' No, and you are down the wrong path if you are trying to make abstract function optional. Hope my suggestions can help.
I wanna ask about design pattern.
Why should I use dependency injection in constructor, not import it ('use statement')?
For example:
in my controller:
class AuthController extends Controller {
public function __construct(UserGateway $userGateway)
{
$this->userGateway = $userGateway;
}
public function doSomething()
{
$this->userGateway->foo();
}
}
Why don't use just like this instead?
use Acme\UserGateway;
class AuthController extends Controller {
public function doSomething()
{
UserGateway::foo();
}
}
Many thanks.
Assuming UserGateway is not laravel facade: here's the biggest advantage of injecting stuff this way: in the future, you might redefine what UserGateway actually is, and supply some other class (most often, it's subclass) instead of it like this:
$this->app->bind(UserGateway::class, function ($app) {
return new NewUserGateway();
});
This is extremely useful for overriding some parts of your code, especially if you're using same packages across multiple projects. And it does not require you to change the AuthController's code.
If UserGateway is a Facade, the only benefit you'll get is a better code navigation with you IDE, since it will know what class exactly are you referencing (assuming that you didn't re-bound it).
This is a follow-up to my previous question about resolving the diamond issue in php.
As I state in that question, I resolve my problem by using traits and passing the instance of the class to the method of the trait. Such as:
trait SecurityTrait
{
public function beforeExecuteRouteTrait($controller, Dispatcher $dispatcher)
{
// Do something that makes use of methods/members of the controller
}
}
class AppController extends Controller
{
use SecurityTrait;
public function beforeExecuteRoute(Dispatcher $dispatcher)
{
return $this->beforeExecuteRouteTrait($this, $dispatcher);
}
}
However, I am still uncomfortable with this as I don't think this is how traits are really supposed to be used. In my reading I haven't found any way in which to access class members in traits (make $this inside a trait refer to the class using it). Is this possible? Or is there another way to implement a similar behaviour?
After reading some of the answers...
Previously I thought I had received errors when using $this->... inside the trait and this led me to believe the trait could not access anything to do with the underlying class. After reading the answers I tried altering my code to use $this->... inside a trait again and it works - which means a typo several weeks ago has given me far too much headache...
The example given previously now looks like this
trait SecurityTrait
{
public function beforeExecuteRoute(Dispatcher $dispatcher)
{
// Do something that makes use of methods/members of the controller
}
}
class AppController extends Controller
{
use SecurityTrait;
}
Much cleaner and more easily understandable but provides the same functionality.
If you use a trait inside a class then that trait has full access to all class's members and vice versa - you can call private trait methods from the class itself.
Think of traits as code that literally gets copy/pasted into the class body.
For example:
trait Helper
{
public function getName()
{
return $this->name;
}
private function getClassName()
{
return get_class($this);
}
}
class Example
{
use Helper;
private $name = 'example';
public function callPrivateMethod()
{
// call a private method on a trait
return $this->getClassName();
}
}
$e = new Example();
print $e->getName(); // results in "example"
print $e->callPrivateMethod(); // results in "Example"
In my view referencing classes in traits is not the best way to use them but there's nothing stopping anyone from doing it.
No, that's exactly what Traits are for. Your class already extends a class so you can't inherit the methods and variables of any other classes.
Think of a Trait like copy/paste for code execution. When a class includes a Trait, it's just as if you had written all that code into the class itself.
I have seen some similar questions but I have yet to find a good solution for this from the interface all the way to the controller.
My Problem:
I have a few different kinds of applications that will require restarts, each has its own logic for restarting the application(SSH,API calls, etc.). I have set up an interface because although different logic, they all will need some similar functions. I have also created 3 classes, one for each app that implements that interface. where I am having issues is understanding the best way to keep the logic as abstracted from the controller as possible.
Some Questions:
Should I also be creating an Abstract class?
Should this be one controller that handles all types and chooses the correct one?
do I simply inject the different classes into the controller?
Code:
RestartInterface.php
<?php namespace Application\Service\Restart;
interface RestartInterface {
public function start();
public function stop();
public function restart();
}
example of implementing class:
<?php namespace Application\Service\Restart\AppOne;
use Application\Service\Restart\RestartInterface;
class AppOneRestart implements RestartInterface {
public function start() {
}
public function stop() {
}
public function restart() {
}
}
How could I use a service provider to keep this as modular as possible?
What is the best practice in this situation, I would like to be able to use many or as little restart implementations as I want.
thanks!
An abstract class is a way to create a base class you don't need your developers instantiating directly because, usually, there is still missing code from it, like, methods were not fully implemented. So you create an abstract which implements the common methods of your concrete restart classes
abstract class Restart {
public function restart() {
}
}
And then you implement one by one of those classes extending your abstract and creating the missing methods:
class AppOneRestart extends Restart implements RestartInterface {
public function start() {
}
public function stop() {
}
}
Option 1
If your whole application can use a single implementation of it and you just need the ability to swap from one to another, because your business somehow changed, a simple binding will do the trick:
App::bind('RestartInterface', 'AppOneRestart');
Option 2
If during a request you might need one or another, you probably will need to implement the Factory pattern: http://en.wikipedia.org/wiki/Factory_method_pattern, so you inject the factory in your controller:
class RestartApiController extends Controller {
public function __construct(RestartFactory $factory)
{
$this->restart = $factory->make('api');
}
}