Where and how do you use PostEloquentRepository? Do you call 'create' from your controller?

It would be nice if you can post your client code.

I guess I just reply it based on your code.

You probably need a service class.

$category = $this->category->byId($category); is problematic because you might be finding a record that might not exists, meaning that you need to validate it in your repository. IMO, validating should not be done in your repository. When you call 'create', that means that you've already validated all the data and you just want to save the data to a persistence storage.

The following classes should give you an idea..I hope.

class PostService
{

	private $postRepository;
	private $categoryRepository;

	public function __construct(PostRepositoryInterface $postRepository, CategoryRepositoryInterface $categoryRepository)
	{
		$this->postRepository = $postRepository;
		$this->categoryRepository = $categoryRepository;
	}

	public function create($title, $content, $category)
	{
		$category = $this->category->byId($category);

		if (!$category) {
			// do something
		}

		return $this->postRepository->create([
			'title' => $title,
			'content' => $content,
			'category' => $category->id
		]);

	}

}

class PostEloquentRepository implement PostRepositoryInteface
{
    protected $post;

    public function __construct(Post $post)
    {
        $this->post = $post;
    }

    public function create(array $data)
    {
        $post = $this->post->create($data);
        return $post->toArray();
    }
}


class PostController 
{	

	private $postService;

	public function __construct(PostService $postService)
	{
		$this->postService = $postService;
	}

	public function create()
	{
		// use post service here
	}

}

Your repository shouldn't extend an interface, it should implement an interface. Big difference.

Injecting the model is the right idea though. You want to start off like this:

class PostRepository implements PostRepositoryInterface {

}

Laracasts has a lot of good stuff on using dependency injection. Check it out.

@AnthonyVipond as much as I love laracasts (I'm a yearly member), recommending to a premium service without even trying to give the OP your opinions and answers is just wrong IMO. 5 lines of post and a premium service recommendation?

Nice catch on the extending interface. I didn't even notice it lol

You can just inject the category model in as well instead of injecting the category repository. I don't see any other methods in your code specifically calling something from the category repository.

Then you could do:

$this->category->with('posts')->where('id', 5)->get();

as you desired.

I don't see what's wrong with me recommending Laracasts either. I see someone who halfway understands the repository pattern and could go to fully understanding it after watching the architecture videos there :) Should recommend Chris Fidao's book as well while I'm at it.

@AnthonyVipond // I don't see either as long as you provide OP something. I mean..this is larval forum, not a place where you just recommend a premium service without providing something to discuss. If we can do that, why don't we just subscribe to Laracast without asking/discussing on this forum?

I'd do what moon0326 suggested - create a service class where you inject both repositories and do the necessary checking. Then, the create function on the post repository can accept a category instance as an optional argument, so it can associate the post with the category if necessary.