Rails API Render Show Page with ID - Ruby

Introduction

In Ruby on Rails, the render method is an important part of the API. It allows you to render a view template and return the result as a response to the client. In this tutorial, we will discuss how to use the render method to show a specific record from the database using its ID.

Prerequisites

You should be familiar with Ruby on Rails and have a basic understanding of MVC architecture.

Getting Started

Let's first create a simple Rails application with a users table in the database. We will use this application to demonstrate how to render a show page with the ID of the user.

1. Create a new Rails application

To create a new Rails application, open your terminal and run the following command:

rails new rails-api-show-page --api --database=postgresql

This will create a new Rails application with the name rails-api-show-page, using the --api option to generate a lightweight API-only Rails application, and the --database=postgresql option to use PostgreSQL as the database.

2. Generate a users resource

Next, let's generate a new resource for the users table in the database. To do this, run the following command:

rails g scaffold User name email

This will generate a new User model with the name and email attributes, a users controller with CRUD actions, and views for each action.

3. Migrate the database

Before we can use the User model and the users table, we need to run the database migrations. To do this, run the following command:

rails db:create
rails db:migrate

This will create the rails-api-show-page_development and rails-api-show-page-test databases and run the users migration to create the users table in the database.

4. Seed the database

Let's seed the users table with some sample data. Open the db/seeds.rb file and add the following code:

User.create(name: 'John Doe', email: 'john.doe@example.com')
User.create(name: 'Jane Doe', email: 'jane.doe@example.com')

Then, run the following command to run the seed data:

rails db:seed

5. Test the application

Let's test the application by starting the Rails server and navigate to the users index page. To do this, run the following command:

rails s

Then, open your browser and navigate to http://localhost:3000/users. You should see a table with two users.

Rendering a Show Page with ID

Now that we have a working Rails application with a users resource, let's render a show page with the ID of a specific user.

1. Define a show action in the controller

First, let's define a show action in the users controller to fetch a specific user from the database and render the show view template. Open the app/controllers/users_controller.rb file and add the following code:

class UsersController < ApplicationController
  before_action :set_user, only: [:show]

  def show
    render json: @user, status: :ok
  end

  private

  def set_user
    @user = User.find(params[:id])
  end
end
```

This will define a `show` action that finds a specific `User` record in the database based on the `id` parameter passed to the URL, sets it as an instance variable `@user`, and renders the record as JSON in the response with an HTTP status of 200 (OK).

### 2. Define a show view template

Next, let's define a view template for the `show` action to show the details of a specific user. Create a `app/views/users/show.json.jbuilder` file and add the following code:

```ruby
json.extract! @user, :id, :name, :email
```

This will define a JSON view template that extracts the `id`, `name`, and `email` attributes from the `@user` instance variable.

### 3. Test the show action

Let's test the `show` action by making a request to the `http://localhost:3000/users/:id` URL, where `:id` is the ID of the user we want to display. For example, to display the details of the user with ID 1, navigate to `http://localhost:3000/users/1`.

You should see a JSON response with the `id`, `name`, and `email` attributes of the user.

```json
{
  "id": 1,
  "name": "John Doe",
  "email": "john.doe@example.com"
}
```

## Conclusion

In this tutorial, we discussed how to use the `render` method to show a specific record from the database using its ID in a Rails API application. We created a simple Rails application with a `users` resource, defined a `show` action in the controller to fetch a specific user from the database, and rendered the record as JSON in the response with an HTTP status of 200 (OK). We also defined a view template for the `show` action to show the details of a specific user.