A comprehensive guide to HTTP status codes in Ruby on Rails

The :status option provides flexibility in customizing the HTTP status code for a Rails response. By default, Rails generates a response with the appropriate HTTP status code, typically 200 OK for successful requests. However, the :status option allows developers to explicitly set the status code, enabling more granular control over response behavior. This option proves particularly useful when the default status code is not suitable for the response, such as returning a 404 Not Found status code for missing resources.

Key Points:

Override default HTTP status code
Granular control over response behavior
Handle scenarios where the default status code is inappropriate

The status classes are as follows:

Informational (1xx): indicates that the request is being processed.
Success (2xx): indicates that the request was successful.
Redirection (3xx): indicates that the client should redirect its request to another resource.
Client Error (4xx): indicates that the client made an error in the request.
Server Error (5xx): indicates that the server made an error in the request.

Each status class has its own associated status codes. For example, the Informational status class has the status codes 100, 101, and 102.

The Ruby on Rails documentation provides a table that lists all possible status codes according to the status classes. The table also includes a description of each status code.

Some of the most used status code

Code	Description	Example
200	OK	A successful request. For example, a request to retrieve a web page would return a 200 status code.
404	Not Found	The requested resource was not found. For example, a request to a URL that does not exist would return a 404 status code.
500	Internal Server Error	An unexpected error occurred on the server. For example, a server crash would return a 500 status code.
302	Found	The requested resource has been moved to a new location. For example, a request to a web page that has been moved to a new URL would return a 302 status code.
403	Forbidden	The user does not have permission to access the requested resource. For example, a request to a web page that is password-protected would return a 403 status code.

Here are examples of how to use some HTTP status codes in Ruby on Rails controllers:

200 OK and 403 Forbidden

class UsersController < ApplicationController
  def show
    if current_user.admin?
      render json: current_user, status: :ok, message: "User is an admin."
    else
      render status: :forbidden, message: "User is not an admin."
    end
  end
end

500 Internal Server Error and 201 Created

class UsersController < ApplicationController
  def create
    user = User.new(user_params)
    if user.save
      render json: user, status: :created, message: "User created successfully."
    else
      render status: :internal_server_error, message: "An error occurred while creating the user."
    end
  end
end

302 Found and 404 Not Found

class ProductsController < ApplicationController
  def edit
    product = Product.find_by_id(params[:id])
    if product
      render :edit, locals: { product: product }, status: :found, message: "Product found."
    else
      render status: :not_found, message: "Product not found."
    end
  end
end