When using Rails ActiveModel :: Serializers When you want to render two json objects, you can nest them in only one or not. This article is written as a memorandum for myself.
When writing the following code in a Rails method, the object you want to nest You will know how to play with it as you like.
users_controller.rb
render json: { hoge: hoge, fuga: fuga }, include: :piyo
Use Rails'as_json method to solve it!
Ruby 2.6 Rails 6.0 active_model_serializers 0.10.10
There are the following four models.
user and facility are 1: N, The product model and user model are not associated. Since the column is not needed this time, it is omitted.
user.rb
class User < ApplicationRecord
belongs_to :facility
end
facility.rb
class Facility < ApplicationRecord
has_many :users
end
product.rb
class Product < ApplicationRecord
#No association
end
When you call the users # show action You need to render both the user and products objects, You also need to retrieve the nested object for user.
users_controller.rb
def show
user = User.find(params[:id])
products = Product.all
render json: { user: user, products: products }, include: ['facility']
end
When I write in the above code and receive a response, I get the following error!
NoMethodError (undefined method `facility' for #<Product:0x00007fed8d885518>):
Clarified to include in the json object to render. But with the above writing style Facility is nested in both the user and products objects. Since the products model and the facility model do not form an association, Of course there is no such method (model?), So Rails says, "facility? I don't know such a method!"
Use the as_json method to format json at the timing of assigning a variable, Specify that the facility model should be nested with include.
users_controller.rb
def show
user = User.find(params[:id]).as_json(include: 'facility')
products = Product.all
render json: {user: user, products: products}, status: :ok
end
This allows you to nest the facility model only in the variable user.
If you want to get data without nesting the facility model because you don't need the facility model, do this.
users_controller.rb
def show
user = User.find(params[:id]).as_json
products = Product.all
render json: {user: user, products: products}, status: :ok
end
I know how to write it, but honestly I don't know why json is formatted without being nested. Are there times when it is nested and times when it is not? Verification required here
Bonus: The as_json options are explained in detail in the article ActiveModel as_json option list. Thank you ~
The official documentation for the Rails as_json method is here: https://railsdoc.com/page/as_json