Question

In my app I have users, schools (groups), and courses. I am trying to set up a model whereby any one of these three models can send any other model a request, and give the request-receiver an option to accept or deny the request. The idea I had was to set up a polymorphic to polymorphic association, so rails would identify the request_sender and receiver’s id and type. My first question is, does it make sense to set up a poly to poly table to achieve this functionality, or should I be trying something different? If a poly to poly table makes sense I included my current controller and db table:

The database table I set up for requests is:

class CreateRequests < ActiveRecord::Migration
  def change
    create_table :requests do |t|

      t.belongs_to :request_sender, polymorphic: true
      t.belongs_to :requestable , polymorphic: true

      t.timestamps
    end

    add_index :requests, [:request_sender_id, :request_sender_type]
    add_index :requests, [:requestable_id, :requestable_type]
  end
end

this is my request controller, the problem I am having is defining methods to determine the class of both the request sender and receiver:

def new
  @request = @requestable.requests.new
end

def create
  @request = @requestable.requests.new(params[:request])
  if @request.save
    redirect_to @requestable, notice: "requested."
  else
    render :new
  end
end

private
def load_requestable
  klass = [School, User, Course].detect { |c| params["#{c.name.underscore}_id"] }
  @requestable = klass.find(params["#{klass.name.underscore}_id"])
end

any help or guidance is greatly appreciated as I am new to both programming and rails, and have very little clue what I am doing haha.

Answer 1

Sure, no reason why this can’t work.

what you’ll need when creating a message is to send in the class_name and ID of the creator and receiver. So let’s say your form sends in:

• receiver_class
• receiver_id
• sender_class
• sender_id

Then, in your MessagesController

def create
  message = Message.new.tap do |m|
    m.sender   = params[:sender_class].classify.constantize.find(params[:sender_id])
    m.receiver = params[:receiver_class].classify.constantize.find(params[:receiver_id])
    m.message  = params[:message]
  end
  if message.save
    redirect_to root_path, notice: "Awesome!"
  else
    render :new
  end
end