issues updating has_many through data in rails

byMR

August 30, 2023

I am working on a project where my models are:

user has_many setups,

setups has_many instruments through instrumentsetups,

instruments has_many setups through instrumentsetups,

instrumentsetups belongs_to setups,

instrumentsetups belongs_to instruments,

right now I have it where you can update all of the params in the setup but I am trying to make it so you can also update which instruments are in the setup at the same time but I am having issues. I am borrowing some code from my create method in the setups_controller to help me update the instruments but I am having an issue where no matter how many new instruments I select it just makes a bunch of copies of the last instrument selected. Here is all of my code in my setups controller:

class SetupsController < ApplicationController
  skip_before_action :authorize

  def index
    render json: Setup.all, status: :ok
  end


  def show
    setup = Setup.find(params[:id])
    render json: setup
  end


  def create
    setup = current_user.setups.create!(setup_params)
    if setup.valid?

      params[:instrument_ids].each do |instrument_id|
        InstrumentSetup.create(setup_id: setup.id,        instrument_id: instrument_id)
      end 
      render json: setup
    else
      render json: { errors: setup.errors.full_messages }, status: :unprocessable_entity
    end
  end

  def update
    setup = Setup.find(params[:id])
    if setup && setup.user_id == current_user.id
      
      params[:instrument_ids].each do |instrument_id|
        InstrumentSetup.update(instrument_id: instrument_id)
      end
      setup.update!(setup_params)
      render json: setup, status: :created
    else
      render json: "Invalid Credentials", status: :unauthorized
    end
  end

  def destroy
    setup = Setup.find(params[:id])
    if setup && setup.user_id == current_user.id
      setup.destroy
      head :no_content
    else 
      render json: "Invalid Credentials", status: :unauthorized
    end 
  end



  private

  def current_user
    User.find_by(id: session[:user_id])
  end

  def setup_params
    params.permit(:name, :description, :photo, :genre, :instrument_ids)
  end

  def authorize
    return render json: {error: "Not Authorized"}, status: :unauthorized unless session.include? :user_id
  end

end

here’s also a photo of how its show up on my front end with only showing multiple copies of the same instrument instead of all of the ones I selected

>Solution :

updating is not like creating, in your update action you have o update the object itself and not the model, since you are retrieving the setup and setup has many instruments through instrumentsetups, you can update like this

def update
    setup = Setup.find(params[:id])
    instruments = Instrument.find params[:instrument_ids]
    if setup && setup.user_id == current_user.id
      setup.update(instruments: instruments)
      setup.update!(setup_params)
      render json: setup, status: :created
    else
      render json: "Invalid Credentials", status: :unauthorized
    end
  end