Proper way to create instances of models with has_many :through relationship - ruby-on-rails

Question

I have the following two classes and I'm struggling to find information about how to properly create an event and register users. Any help would be greatly appreciated - my code is below
class UserEvents < ActiveRecord::Base
belongs_to :user
belongs_to :event
end
class User < ActiveRecord::Base
has_many :user_events
has_many :events, :through => :user_events
end
class Event < ActiveRecord::Base
has_many :user_events
has_many :attendees, :class_name => "User", :through :user_events
end
Controller action for creating an event
def create
new_event = event.new(event_params)
current_user.events << new_event
new_event.attendees << current_user
if new_event.save and current_user.save
render json: new_event, status: :ok
else
render json: { errors: "Creation failed" }, status: :unprocessable_entity
end
Am I going about this correctly? Should I be using an array of ID's to keep track of the attendees instead? I've also seen it done in ways similar to:
current_user.events.create ( ... )
I'm just not sure which approach would be best to take

Answer 1

You can setup your event to accept nested attributes, then created all the necessary objects with a single save. Here's an example:
class Event < ActiveRecord::Base
has_many :user_events
has_many :attendees, :class_name => "User", through: :user_outings
accepts_nested_attributes_for :user_events, allow_destroy: true
end
Then modify event_params in your controller to accept attributes for user_events. Example:
def event_params
params.permit([
:..event attributes...,
user_events_attributes: [...user event attributes here...]
])
end
If it's only ever going to be the current user going to a new event, then this is overkill. But if you're adding other users to the event at event creation time, then this is how you'd do it.
If it's just the current user, then you can modify your create action to look like:
def create
new_event = event.new(event_params)
new_event.attendees << current_user
if new_event.save and current_user.save
render json: new_event, status: :ok
else
render json: { errors: "Creation failed" }, status: :unprocessable_entity
end
Edit: You can also do accepts_nested_attributes and use attendees but you may need to use the inverse_of option in your model. See https://robots.thoughtbot.com/accepts-nested-attributes-for-with-has-many-through for more details.