Question

This is a consistency problem that I’m running into often.

Let’s consider a typical Forum:

• User can create Posts
• Posts belong to a Topic
• Posts also belong to the User that created them

What’s the best practice for choosing between these two options:

# Initialize @post on the User
def create
  @post = current_user.posts.build(params[:post])
  @post.topic_id = @topic.id
  if @post.save
    ...
  end
end

Or

# Initialize @post on the Topic
def create
  @post = @topic.posts.build(params[:post])
  @post.user_id = current_user.id
  if @post.save
    ...
  end
end

Or is there a better way, considering that, in the above examples, either @post’s user_id or topic_id would have to be added to attr_accesssible (feels hacky)?

Answer 1

You never need to monkey with IDs or attr_accessible. If a User has_many Posts and a Topic has_many Posts than you can do

# Initialize @post on the User
def create
  @post = current_user.posts.build(params[:post])
  @post.topic = @topic #assuming you've gotten the topic from somewhere
  if @post.save
    ...
  end
end 

There really isn’t a big difference in building from the user or from the topic, but going from the user seems more natural to me.