Model Association (Rails 5 API)

Question

I have a Character model that has a CharClass and ClassPerks child.

Currently I am duplicating my logic a lot by manually assigning data.

My Character index and create:

def index
 @campaign = Campaign.find_by_id(params[:campaign_id])
 @characters = @campaign.characters
 render json: {
 characters: @characters
 }
end
def create
 @campaign = Campaign.find_by_id(params[:campaign_id])
 @charClass = CharClass.find_by_id(params[:character_char_class_id])
 @character = @campaign.characters.new(character_params)
 @character.char_class_id = params[:character_char_class_id]
 if @character.save!
 render status: 201, json: {
 message: "Successfull added this character to the campaign!",
 character_name: @character.character_name + ' the ' + @charClass.class_name,
 character_class: @charClass.class_name,
 character_level: @character.character_level,
 character_experience: @character.character_experience,
 character_gold: @character.character_gold,
 character_perks: get_names(@character.character_perks),
 character_image: @character.character_image
 }
 else
 render status: 404, json: {
 message: "Something went wrong: Check line 24 of the Character Controller"
 }
 end
end

I am manually assigning character_class and character_image despite both of these ALWAYS being the same based on their character_class.

Inside of the character.rb I am doing this to assign them post-create:

 after_create :add_perks, :save_class
 def add_perks
 self.class_perks.each do |perk|
 self.character_perks.create(class_perk_id: perk.id)
 end
 end
 def save_class()
 case self.char_class_id
 when 1 # Mindthief
 self.character_image = "https://gloomhavenil.files.wordpress.com/2017/12/11849117_616974988445216_217288420_n.jpg?w=480"
 self.character_class = "Mindthief"
 self.save
 when 2 # Tinkerer
 self.character_image = "http://www.cephalofair.com/wp-content/uploads/2015/04/Quatryl-Tinkerer.jpg"
 self.character_class = "Tinkerer"
 self.save
 # when 'Sawbones'
 # else
 end
 end
end

It is working, but I am unsure how to do this better/appropriately. I removed useless fields but you'll see below I have the relations set up appropriately.

 create_table "char_classes", force: :cascade do |t|
 t.string "class_name"
 t.string "class_image"
 t.string "class_perks"
 t.datetime "created_at", null: false
 t.datetime "updated_at", null: false
 end
 create_table "characters", force: :cascade do |t|
 t.string "character_class"
 t.string "character_image"
 t.integer "char_class_id"
 t.index ["campaign_id"], name: "index_characters_on_campaign_id"
 t.index ["char_class_id"], name: "index_characters_on_char_class_id"
 end

I can do Character.first.char_class.class_name and I will get the appropriate result; so I am back to assuming this method I'm following is very incorrect.

Answer 1

You need to use ActiveModelSerializers (AMS) to serialize your json responses based upon the instances of your class.

class CampaignsController < ApplicationController
 def index
 render json: { characters: campaign.characters }
 end
 def create
 @character = campaign.characters.new(character_params.merge(char_class_id: char_class.id))
 if @character.save!
 render json: @character, serializer: CharacterSerializer, status: 201 # This should automatically be formatted by AMS
 else
 not_found('Something went wrong: Check line 24 of the Character Controller')
 end
 end
 private
 def campaign
 @campaign ||= Campaign.find_by_id(params[:campaign_id])
 end
 def char_class
 @charClass ||= CharClass.find_by_id(params[:character_char_class_id])
 end
end

This is how you AMS class for Character class should look like

class CharacterSerializer < ActiveModel::Serializer
 attributes :message, :character_name, :character_class, :character_level, :character_experience, :character_gold, :character_perks, :character_image
 def message
 'Successfull added this character to the campaign!'
 end
 def character_name
 return object.character_name + ' the ' + character_class # check the associations
 end
 def character_class
 object.charClass.class_name
 end
 def character_perks
 # Unsure what this get names methods does so im leaving it for you to refactor
 get_names(object.character_perks),
 end
end

Also add this to your ApplicationController

class ApplicationController < ActionController::Base
 # Add this to your application controller
 def not_found(message = nil)
 render json: { message }, status: 404
 end
end

I'll update the refactored model class based upon your info soon. Hope this helps for now.