Welcome back! In this lesson, we will explore how to set up a POST request in a Ruby on Rails ToDo application to create new ToDo items. This marks an essential step in building our RESTful API, enabling users to add new tasks to their ToDo lists.
By the end of this lesson, you will be able to create a new ToDo item using a POST
request. This skill will allow your application to handle new data input from users, making it interactive and dynamic. Let's get started!
The TodosController
is responsible for handling requests related to ToDo items. In this lesson, we will focus on setting up the create
action within this controller to enable the creation of new ToDo items.
Below is the code required to set up the TodosController
:
Ruby1# app/controllers/todos_controller.rb 2class TodosController < ApplicationController 3 def create 4 todo = TodoService.create(todo_params) 5 render json: todo, status: :created 6 end 7 8 private 9 10 def todo_params 11 params.require(:todo).permit(:title, :description) 12 end 13end
Explanation:
create
action: This action receives the incoming POST
request, invokes the TodoService.create
method to handle the creation of a new ToDo item, and then renders a JSON response with the created item and a created
status. As mentioned previously, Rails automatically links the POST
request on /todos
to the create
action in the TodosController
.todo_params
: This private method ensures only the permitted parameters (title
and description
) are passed to the model, protecting against unwanted data. In Rails, such strong parameters help prevent unwanted data from entering our database by ensuring only allowed attributes are passed through the controller actions. This provides a layer of security and data integrity:
params.require(:todo)
: Ensures that the parameters sent with the request contains a todo
object.permit(:title, :description)
: Specifies the attributes that are allowed within the todo
object, filtering out any other input.By using strong parameters, we enforce strict criteria on incoming data, enhancing the security and reliability of our application.
To keep our code modular and maintainable, we delegate the business logic for creating ToDo items to the service class TodoService
. This separation of concerns is a standard best practice in Rails applications.
Here is how we implement the TodoService.create
method:
Ruby1# app/services/todo_service.rb 2class TodoService 3 def self.create(params) 4 todo = { id: @todos.size + 1, **todo_params } 5 @todos << todo 6 todo 7 end 8end
Explanation:
todo = { id: @todos.size + 1, **todo_params }
: This line creates a new ToDo item with a unique ID based on the current size of the @todos
array and the provided parameters.@todos << todo
: The newly created ToDo item is added to the @todos
array.todo
: The new ToDo item is returned.This approach makes our TodosController
more concise and focused purely on handling HTTP requests and responses.
After creating a new ToDo item, we need to provide feedback to the client indicating that the operation was successful. We do this using the render
method in our create
action:
Ruby1def create 2 todo = TodoService.create(todo_params) 3 render json: todo, status: :created 4end
Explanation:
render json: todo
: Converts the ToDo object to JSON format, making it suitable for API responses.status: :created
: Sets the HTTP status code to 201 Created
, indicating that a new resource was successfully created.By providing a clear JSON response and an appropriate status code, we ensure that clients interacting with our API receive meaningful feedback.
In this lesson, we covered the critical steps needed to set up a creation query for adding ToDo items in a Ruby on Rails application. We:
TodosController
and the create
action.todo_params
method.TodoService
to handle the business logic.As we move forward, you’ll get the chance to apply what you’ve learned in practice exercises. These exercises will help reinforce the concepts and ensure you are comfortable creating and managing POST
requests in a Rails application.
Keep up the excellent work, and let's continue building our ToDo app!