How do I define my endpoint?

Question

In my API I want an endpoint to provide a subject account's ID and have it return other account records associated with the subject. My models are as follows:

This is my main account model. Both subjects and associates are of type account:

class TabAccount < ApplicationRecord    
  has_many :subjects, through: :subject_tab_account_relationships, source: :subject
  has_many :subject_tab_account_relationships, foreign_key: :id_associate, class_name: "TabAccount"

  has_many :associates, through: :associate_tab_account_relationships, source: :associate
  has_many :associate_tab_account_relationships, foreign_key: :id_subject, class_name: "TabAccount"
end

This is my account relationship model. This provides the many-to-many self-join relationships between subjects and associates:

class TabAccountRelation < ApplicationRecord
  belongs_to :ref_relationship_type

  belongs_to :subject, foreign_key: "id_subject", class_name: "TabAccount"
  belongs_to :associate, foreign_key: "id_associate", class_name: "TabAccount"
end

I know that works because I'm able to use the model inside my Rails code but I'm not entirely sure how to expose this relationship through an endpoint. I know in the routes map file you're supposed to add child resources to a parent resource, but I'm not sure what's the child in this case. This is what I have so far for my route mapping:

resources :tab_accounts do
  resources :associates
end

And here's my account controller:

# GET /tab_accounts/:id_subject/associates
# GET /tab_accounts/:id_subject/associates.json
def index
  if params[:id_subject]
    _limit = if params[:limit].present? then params[:limit] else 100 end
    @tab_accounts = TabAccount.find(params[:id_subject]).associates.limit(_limit)
  else
    @tab_accounts = TabAccount.offset(params[:offset]).limit(_limit)
  end
end

And here's my output to stderr:

Started GET "/tab_accounts/2646/associates.json?limit=5" for 127.0.0.1 at 2018-03-21 22:51:54 -0400
ActionController::RoutingError (uninitialized constant AssociatesController):

Has anyone ever exposed aliases/sources through endpoints before? How did you do it? Am I close to getting it right?

Answer 1

Instead of adding nested resources you can add additional routes to your existing resource. See http://guides.rubyonrails.org/routing.html#adding-more-restful-actions .

So instead of using this:

resources :tab_accounts do
  resources :associates
end

you can switch to this:

resources :tab_accounts do
  member do
    get :associates
  end
end

You would then add the corresponding associates action to your existing Accounts controller.