Best Practices for Defining API Routes for One-to-Many Relationships

You should define a CommentController with an index method that takes a post as an argument. By leveraging route model binding you can have instant access to the post model object and then access the comments from a relationship defined within the post model (You said you know how to go about this so I wont dwell on it).

The setup will then be as follows;

routes file (api.php)

Route::get('/api/post/{post}/comments', 'CommentController@index');

CommentController.php (index method)

public function index (Post $post)
{
    $comments = $post->comments;

    if (request()->wantsJson()) {

        return response()->json($comments);

    }

    return view('your_view_file', compact('comments'));
}

Assuming you are using the same controller for the API and Web business logic, you can use the condition indicated to return json data for APIs or proceed with loading a view for web apps.

Thanks for your fast reply! I particularly appreciate the suggestion to make use of route model binding (a nice feature of Laravel indeed). I might be doing something else wrong, but the main issue I found is that when I use:

return response()->json($post->comments());

I get an empty object returned {}.

However, when I use:

return $post->comments()->get();

I get a fully populated array of objects, eg:

[
    {
        "id": 1,
        ...
    },
    {
        "id": 2,
        ...
    }
]

For reference, my Post model's comments() method is implemented as follows:

public function comments() {
        return $this->hasMany('App\Comment');
    }

The get() approach works for me and I can use that, however I'm curious as to why the json() approach didn't work for me. Any idea?

Thanks again.

It's not about json. You should understand the difference between using/not using parenthesis in relationships. When you write:

$post->comments()

it just compounds with QueryBuilder and lets you continue query. So, usually you have to say what do you want to get, like collection of all the items :

$post->comments()->get();

or just one first item:

$post->comments()->first();

or you want to add some condition to query:

$post->comments()->where('body', 'like', 'laravel')->get();

etc. At the same time, you can use:

$post->comments

to get all comments for the post. $post->comments()->get() will be executed under the hook (be sure you aware of N + 1 problem). For better understanding what's going on, recommend you to read the topic about relationships

And yes, try this:

return response()->json($post->comments);
// or
return response()->json($post->comments()->get());

Ahh, thank you for pointing out the parentheses! I failed to notice that in one case I was calling a method and in another accessing a property :) That was the issue, thanks. (And yes, read through the relationships section and aware of the N + 1 problem).

Thanks for your help @kisiara and @serhii75

@digitalsolomon always glad to help