Question

Here is my User controller show action

def show
    @public_groups = Group.public
    @groups_member = @user.groups_as_member
    @groups_as_owner = @user.groups_as_owner

    @random_items = []
    @assignments = []
    unless @groups_member.nil?
      until @random_items.count == 5 do
        random_groups = @groups_member.sort_by{rand}.slice(0,5)
        random_groups.each do |group|
          assignments = Assignment.where(:group_id => group.id).limit(5).all
          #assignments = Assignment.find_by_group_id(group.id)
          y = Post.find_by_id(assignments.rand.post_id)
          @random_items << y
        end
      end 
    end
  end

I think it might be the way I am declaring the instance variable arrays @random_items and @assignments. I have no idea what the problem is though because my development and production servers don’t give any compilation errors or anything.

When I comment out the big block of logic starting with the array declarations the site works.

Answer 1

I’d suggest you to perform a refactoring before you can find an error. Some principles before:

• Any dataflow is about model layer responsibility
• instance variables are use to share objects between ActionPack layers (controller and view)
• use object’s attributes instead of instance variables to easy to test
• use associations and minimize Arel method and just find in controllers

With according to your code, it can be rewritten with:

  # User model
  def random_items
    return unless groups_as_member
    random_groups = groups_member.sort_by{rand}.slice(0,5)

    random_groups.each do |group|
      return if randorm_groups.length > 5
      assignments = group.assignments.limit(5)
      if y = Post.rand_by_post(assignments)
        random_groups << y
      end
    end

    return random_groups
  end


  # Post model
  def self.rand_by_post(assignments)
    find_by_id(assignments.rand.post_id)
  end

Once you have the logic clear, you can find the bug and cover it with tests.