Laravel 5 Controller Best Practices

I'm using Lumen as REST API. I have a Post model and a Comment Model.

Post.php

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

Comment.php

public function post(){
return $this->belongsTo('App\Post');
}

I also have Resource controllers for both these models. If I want to get all the comments on a particular post, where do I write that logic? In the PostController (because I'll be filtering comments by Post) or in the CommentController (because I'm fetching comments after all)? Which is the better way? Or is there some other way altogether (like creating a separate controller) ? I just want to get the structure right and write clean code. Any help will be greatly appreciated.

I personally like to follow a pattern whereby a controller doesn't have any custom methods. Thus you end up with lots of very thin controllers with generic resource methods like `index` `update` `store` `create` `edit` `destroy`.

so for you example
I would have `/Posts/CommentController.php` with resource methods

It depends on the requirements actually and how are you handling the data. Normally, no comments display on the post listing page. so it would be better just to send posts without comments which means the logic will be in post controller.
For post details page you will be sending the post with comments so the logic would still be in Post Controller. Something like this:

Post::where('id', $id)->with('comments')->first();
It would be in comments controller if you just need to send comments for specific post without post object.

Comment::where('post_id', $post_id)->get();
If you have any confusion ask me.