Dependency inversion issue in php. (Repository Pattern) - php

Question

I am implementing a repository pattern in Laravel, and it seems to be very tedious. For example, let's say I have products then I have to create a ProductRepository interface then a ProductRepository class that implements that interface, now I have some very generic methods on the ProductRepository like:
retrieveAll
store
update
delete
And now I have to do the same thing for ingredients. It would be nice if I could simply create a ModelRepository interface with all those generic methods and implement it by passing a generic data type (namely the model), something similar to Java Generics:
<?php
interface ModelRepositoryInterface<T> {
function retrieveAll(): Collection<T>;
function store(T $item);
function update(int $id, T $data);
function delete(int $id);
}
But since php doesn't support generics how can I achieve this simplicity?

Answer 1

You can create a RepositoryServiceProvider to bind your repository interfaces to actual classes.
You can create a abstract Repository class with retrieveAll, store, update, delete and extend your Repositories and implement the interface. I have included below example with magic functions to be able to eloquent methods if I don't have any customization.
The below is not tested but its just to get the idea.
<?php
namespace App\Repositories;
use Illuminate\Database\Eloquent\Builder;
use Illuminate\Database\Eloquent\Model;
abstract class AbstractRepository implements RepositoryInterface
{
/**
* #var Builder|Model
*/
protected $model;
/**
* #return mixed
*/
public function getModel()
{
return $this->model;
}
/**
* #param array $columns
* #return \Illuminate\Database\Eloquent\Collection|Model[]
*/
public function all($columns = ['*'])
{
return $this->model->all($columns);
}
/**
* #param $name
* #param $arguments
* #return mixed
*/
public function __call($name, $arguments)
{
return $this->model->{$name}($arguments);
}
}
OrderRepository
<?php
namespace App\Repositories;
use App\Models\Order;
use Illuminate\Support\Facades\Date;
use Illuminate\Support\Facades\DB;
class OrderRepository extends AbstractRepository implements OrderRepositoryInterface
{
/**
* OrderRepository constructor.
* #param Order $model
*/
public function __construct(Order $model)
{
$this->model = $model;
}
public function countPaid(): int
{
return $this->model->paid()->count();
}
/**
* #return int
*/
public function countReady(): int
{
return $this->model->ready()->count();
}
/**
* #return int
*/
public function countCancelled(): int
{
return $this->model->cancelled()->count();
}
}
OrderRepositoryInterface
<?php
namespace App\Repositories;
interface OrderRepositoryInterface
{
}
RepositoryServiceProvider
<?php
namespace App\Providers;
use App\Repositories\OrderRepository;
use App\Repositories\OrderRepositoryInterface;
use Illuminate\Support\ServiceProvider;
class RepositoryServiceProvider extends ServiceProvider
{
/**
* Register any application services.
*
* #return void
*/
public function register()
{
$this->app->bind(OrderRepositoryInterface::class, OrderRepository::class);
}
/**
* Bootstrap any application services.
*
* #return void
*/
public function boot()
{
//
}
}
RepositoryInterface
<?php
namespace App\Repositories;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Support\Collection;
interface RepositoryInterface
{
function retrieveAll(): Collection;
function store(Model $item);
function update(int $id, Model $data);
function delete(int $id);
}