Question

I have the following code in a likes_controller and it works fine as long as a thing has an owner. If not, it breaks.

  def create
    @thing = Thing.find(params[:like][:liked_id])
    user = @thing.owner
    current_user.like!(@thing)
    current_user.follow!(user)
    respond_with @thing
  end

I’ve tried using

user = @thing.owner if @thing.owner.exists?

but I get a NoMethodError:

NoMethodError in LikesController#create

undefined method `exists?' for nil:NilClass

How do I check for the existence of an owner?

I also now notice I’ll have to put the second line (current_user.follow!(user)) in the block or it will break again…

Edit: This worked (using @Amadan’s answer):

def create
    @thing = Thing.find(params[:like][:liked_id])
    current_user.like!(@thing)
    user = @thing.owner
    if user
      current_user.follow!(user)
    end
    respond_with @thing
  end

Additional information: In case anyone ever actually uses this, I should point out that one more small change is necessary to get this to work. The above code errors out if a user tried to like a thing when they are already following the thing‘s owner.

so instead of

if user

I used

if user && !current_user.following?(user)

Hope this is helpful.

Answer 1

Insert this line:

return unless user

Some might not like it on stylistic grounds, so you can use this alternative:

def create
  @thing = Thing.find(params[:like][:liked_id])
  user = @thing.owner
  if user
    current_user.like!(@thing)
    current_user.follow!(user)
    respond_with @thing
  end
end