Rails multiple nested form issue

Question

I have a model Comment that belongs_to :post and the Post model in turn belongs_to :group so basically I want a group to have posts and the posts to allow comments. I'm running into an issue trying to figure out how to do nesting 3 levels like this.

in my comments controller would I do something like this?

      before_action :set_group, only: [:index, :show, :new, :edit, :create, :update]
      before_action :set_post, only: [:index, :show, :new, :edit, :create, :update]
      before_action :set_comment, only: [:show, :edit, :update, :destroy]

      def new
        @comment = @group.posts.comments.new
      end

    private
    # Use callbacks to share common setup or constraints between actions.
    def set_comment
      @comment = Comment.find(params[:id])
    end

    def set_post
      @post = Post.find(params[:post_id])
    end

    def set_group
      @group = Group.find(params[:group_id])
    end

    # Never trust parameters from the scary internet, only allow the white list through.
    def comment_params
      params.require(:comment).permit(:content, :post_id, :user_id)
    end

I was reading up on accepts_nested_attributes_for should I be adding this to my Post model? or my Group model?

The error I'm getting is `

NoMethodError in CommentsController#new
undefined method `comments' for #<Post::ActiveRecord_Associations_CollectionProxy:0x007f2d26044020>`

it's passing parameters for group and post though.

Request

Parameters:

{"group_id"=>"25", "post_id"=>"8"}

Answer 1

You cannot write @group.posts.comments because @group.posts is not 1 post. It's an association (it's many posts). However, in the new method you already have the post loaded. So you can:

def new
  @comment = @post.comments.build
end