1

I am sending a JSON from app1 to app2 whenever a model is created in app1. I need to create a similar model in app2 along with the nested attributes. I am able to create the model but not able to figure out how to create the nested attributes model for the same in app2. How can I do that in the same controller?

models in app1

class Author
  has_many :books, dependent: :destroy
  accepts_nested_attributes_for :books
end

class Book
  belongs_to :author
end

books_controller.rb in app1

def new
  @author = Author.new
  @books = @author.books.build
  end

def create
  @author = Author.new(author_params)

  if @author.save
    redirect_to author_path(@author), notice: 'Author was successfully created.'
  else
    render :new
  end
end

def author_params
  params.require(:author).permit(:name, books_attributes: [:id, :book_name, :publisher]) if params[:author]
end

api in app1

def self.create_or_update_author_in_app2(auth)
  app2_author = {}
  app2_author[:author_id_in_app1] = auth.id
  app2_author[:name] = auth.name
  app2_author[:app2_books_attributes] = auth.books.as_json(except: 'app1_author_id')
  response = API.post( 'create_or_update_author', body: { request: { author_data: author_data, authenticate: {auth_key: key} } } )
end

models in app2

class App2Author
  has_many :app2_books
end

class App2Book
  belongs_to :app2_author
end

controller in app2

def create_or_update_author
  response = params['request']['app2_author']
  app2_author = App2Author.find_or_create_by(author_id_in_app1: response['author_id_in_app1'])
  author.update!(name: response['name'])
  app2_author.update_attributes(response['app2_books_attributes']) unless app2_author  
end

At present, App2Author instances are being created in app2 but how can I create the associated books from the same json?

response received by controller in app2

    Parameters: {"request"=>{"app2_author"=>{"author_id_in_app1"=>"16", "name"=>"Author 1", "app2_books_attributes"=>[{"id"=>"43", "book_name"=>"Book 1", "publisher"=>"Publisher 1", "created_at"=>"2019-07-25 15:26:57 +0530", "updated_at"=>"2019-07-25 15:26:57 +0530"}, 
{"id"=>"43", "book_name"=>"Book 1", "publisher"=>"Publisher 1", "created_at"=>"2019-07-25 15:26:57 +0530", "updated_at"=>"2019-07-25 15:26:57 +0530"}, 
{"id"=>"43", "book_name"=>"Book 1", "publisher"=>"Publisher 1", "created_at"=>"2019-07-25 15:26:57 +0530", "updated_at"=>"2019-07-25 15:26:57 +0530"}, 
{"id"=>"43", "book_name"=>"Book 1", "publisher"=>"Publisher 1", "created_at"=>"2019-07-25 15:26:57 +0530", "updated_at"=>"2019-07-25 15:26:57 +0530"}]}, "authenticate"=>{"auth_key"=>"my_key"}}}
Improve this question
4
  • Can you share the sample response from app1? Commented Jul 25, 2019 at 5:56
  • I have added the response received by app2. Commented Jul 25, 2019 at 6:34
  • can a book belong to multiple authors? Commented Jul 25, 2019 at 6:45
  • No. In my case it is one to many relationship only. Commented Jul 25, 2019 at 7:01

1 Answer 1

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1

The code bellow is just an idea how you can handle this.

models in app2

class App2Author
  has_many :app2_books

  # it's better to keep business logic in models.
  def update_info(data)
    name = data['name']
    data['author_books'].each do |book|
      books << Book.new(book)
    end
    save!
  end
end

class App2Book
  belongs_to :app2_author
end

controller in app2

def create_or_update_author
  request = params['request']['author_data']
  author = App2Author.find_or_create_by(author_id_in_app1: request['author_id_in_app1'])
  author.update_info(request)
end

Anyway to be hones with you it's not a good approach. Rails has default mechanism to create associated objects. TO make it work in the right way you need:

1) add accepts_nested_attributes_for :app2_books to App2Author model.

class App2Author
  has_many :app2_books
end

2) in the first app build valid hash with parameters and send to the second app . Something like:

app2_author: { id: 1, name: 'Author name', app2_books_attributes: [:app2_author_id, :book_name, :publisher]}

3) In the second app in controller do something like this:

author = App2Author.find_or_create_by(id: params[:id])
author.update(params) #in case the params hash is valid

that will create associations automatically.

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4 Comments

Ok. Got it! I have one query. How can I delete author_id from each nested attribute in json?
you can specify keys while using :to_json method. apidock.com/rails/Hash/to_json Another option is to use custome method where you prepare hash with valid structure. if you find the answer helpful - please mark as a solution.
I made the changes you said but I still not able to create or update the associations. Is it because I am just trying to update_attributes and not create?
@user001 my bad. I updated 3) point. instead of using update_attributes you can use :update method.

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