How to use Rails .build to create a user with a stripe subscription

问题

I'm using Rails + Devise along with Stripe for billing. I'm working to create a controller method that creates a user with a subscription at the same time but am running into errors. My controller method:

def signup_w_cc
    @user = User.new(:email => params[:user][:email]
    @user.subscriptions.build(:stripe_card_token => params[:stripe_card_token],
                                              :plan_id => 1,
                                              :quantity => 1)
    @user.save
end

This is failing, when I do @user.save, the subscription model is not getting the required user_id field. Am I using build incorrectly? The idea is not to create the user and then the subscription as they both need to commit or rollback at the same time.

user.rb

  has_many :subscriptions

subscription.rb

belongs_to :user

thx

回答1:

Yes, your subscription object won't have an user_id because the user is not persisted yet. There is no id available.

To fix, try to change the order to save user at first. Then @user.subscription will have an user_id attached.

@user = User.new(:email => params[:user][:email]
@user.save # Save and get id at first.
@user.subscriptions.build(:stripe_card_token => params[:stripe_card_token],
                                          :plan_id => 1,
                                          :quantity => 1)

回答2:

I believe that if you want this kind of awareness out of your relations you'll need to add inverse_of options to them:

User

has_many :subscriptions, inverse_of: :user


Subscription

belongs_to :user, inverse_of: :subscriptions

For more on the inverse_of option, search this page for the term inverse_of until you get down to the has_many code: http://apidock.com/rails/ActiveRecord/Associations/ClassMethods

Does that help?

来源：https://stackoverflow.com/questions/18564224/how-to-use-rails-build-to-create-a-user-with-a-stripe-subscription