IntelliJ IDEA 2021.3 Help

Create and run your first Rails application

This tutorial will show you how to create and run the most simple Rails project in IntelliJ IDEA.

Before starting this tutorial, do the following:

We'll perform all steps using IntelliJ IDEA installed on macOS.

Create a Rails application

To create a Rails application from scratch, do the following:

  1. Run IntelliJ IDEA and click New Project on the Welcome Screen.

  2. In the New Project dialog, select Ruby on Rails on the left pane. Then, select the required Ruby interpreter in Project SDK and choose the Rails version. Click Next.

    New project dialog / Ruby on Rails
  3. On the next page, specify the project name and location. Click Finish.

    New project dialog
  4. IntelliJ IDEA creates a new Rails application, installs the gem dependencies mentioned in Gemfile, and installs JavaScript dependencies mentioned in the project's package.json file. You can see this process in the Run tool window.

    Generating Rails Application for a project
  5. After installing all dependencies, you can see a project structure in the Project tool window (Alt+1) on the left. On the right, IntelliJ IDEA automatically opens main project files in the editor.

    New Rails Application

    If you have Git installed in your operating system, generating a new Rails application also initializes a Git repository. You can learn how to work with Version control systems in IntelliJ IDEA from the Version control section.

Start a web server

Now we have a functional Rails application already. To see it in action, you need to start a web server. Perform the following steps to do this:

  1. Press Ctrl twice and start typing development.

  2. Select the Development run configuration from the list and press Enter.

    Run Development configuration
  3. IntelliJ IDEA will show the process of preparing the application to run.

    Rails server output
  4. Copy the address used by a web server, insert it to the browser’s address bar and press Enter to see the Rails default information page.

    Rails default page

Create a controller and view

Now let’s create a new page. To do this, you need to create a controller and a view.

  1. Press Ctrl twice and start typing controller. In the invoked list, select rails g controller and press Enter.

    rails g controller
  2. In the invoked Add New Controller dialog, set the controller name to Welcome and add one action called index. Click OK.

    Add New Controller
  3. IntelliJ IDEA will create a controller, view, and several other files. This process will be displayed in the Run tool window. In this window, click the index.html.erb file.

    generate script output
  4. In the opened index.html.erb file, delete all of the existing code in the file, and replace it with the following single line of code:

    <h1>Hello, Rails!</h1>
  5. To see the result, hover your mouse pointer over the view code, and then select the desired browser from the pop-up.

    Show in browser
  6. The index page will be opened in a selected browser.

    Hello Rails
Last modified: 30 November 2021