Rails Resource Routing: Destroy

Learning Goals

Delete a resource using Rails

Introduction

In this lesson, we'll continue working on our Bird API by adding a destroy action, so that clients can use our API to delete birds. To get set up, run:

$ bundle install
$ rails db:migrate db:seed

This will download all the dependencies for our app and set up the database.

HTTP Verb	Path	Controller#Action	Description
GET	/birds	birds#index	Show all birds
POST	/birds	birds#create	Create a new bird
GET	/birds/:id	birds#show	Show a specific bird
PATCH or PUT	/birds/:id	birds#update	Update a specific bird
DELETE	/birds/:id	birds#destroy	Delete a specific bird

Deleting a Bird

We're at the last step on our journey to becoming CRUD experts! Our goal is to give users the ability to delete birds via the API. To start, we'll need to set up a route to handle a DELETE /birds/:id request. We can do so by adding :destroy to our resources:

resources :birds, only: [:index, :show, :create, :update, :destroy]

And since we're now using all five RESTful routes, we can omit the only option:

resources :birds

Running rails routes will show us all the RESTful routes in our application, plus our custom route:

$ rails routes
Prefix Verb   URI Pattern               Controller#Action
 birds GET    /birds(.:format)          birds#index
       POST   /birds(.:format)          birds#create
  bird GET    /birds/:id(.:format)      birds#show
       PATCH  /birds/:id(.:format)      birds#update
       PUT    /birds/:id(.:format)      birds#update
       DELETE /birds/:id(.:format)      birds#destroy
       PATCH  /birds/:id/like(.:format) birds#increment_likes

We'll also need to add a destroy action to our controller where we'll be deleting the bird from the database:

def destroy
  bird = Bird.find_by(id: params[:id])
  if bird
    bird.destroy
    head :no_content
  else
    render json: { error: "Bird not found" }, status: :not_found
  end
end

In this controller action, our goal is to:

Find a bird using the ID from the route params
Remove it from the database with bird.destroy

You'll also notice that instead of rendering a JSON response, we're returning head :no_content if our bird was successfully deleted. :no_content will give a 204 status code, indicating that the server has successfully fulfilled the request and that there is no content to send in the response. We're also not sending any payload of data in the body of the request.

One thing to watch out for: if the API doesn't return JSON data, and you try to read the response data from a fetch request, you will get an error:

fetch("http://localhost:3000/birds/3", {
  method: "DELETE",
})
  .then((r) => r.json()) // this line will error out, because there is no JSON to parse!
  .then((data) => console.log(data));

Depending on your needs, you could send back a JSON response to verify that the request was completed successfully. For example, json-server handles a successful delete request by sending an empty object:

bird.destroy
render json: {}

Ultimately, you can decide which option you prefer based on how you'll use this data in your client application.

Make sure to test these out in Postman to see the difference between using head and render.

Conclusion

Now that we've covered the Delete action, you can perform all four CRUD actions with Rails and do so following RESTful conventions!

Check For Understanding

Before you move on, make sure you can answer the following question:

What options did you learn about in this lesson for returning information to your users about the status of a delete request?