Rapid Prototyping with Rails: Lesson 2, Nested Routes

Comments - using Nested Routes

def create
    @post = Post.find(params[:post_id])
    @comment = Comment.new(params.require(:comment).permit(:body))
    @comment.post = @post
  end

OR

def create
    @post = Post.find(params[:post_id])
    @comment = @post.comments.build(params.require(:comment).permit(:body))
  end

What we've covered:

1. Creating a Nested Resource

2. Creating a model-backed form in a nested resource way... to generate a nested URL

3. In your controller Create action, you must set up the parent object in the controller action, so that it can be called on in your form_for

4. Under the error condition, you have to render 'posts/show' rather than 'new'