Building a new Ruby on Rails application

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What are we building?

Let's learn Rails by building a simple web application. Let's name it granite, after a type of rock.

The application will be a simple todos for the whole company of small size. The application will have the following features.

  • Users will be able to prioritize the tasks by starring them. These starred tasks will be shown first in the list.
  • Users can toggle the task as pending or done.
  • Task creators can delete/edit the task.
  • Users can add comments to the tasks. These comments cannot be edited/deleted.

Our goal is to learn the process of writing a Ruby on Rails application with React.js.

Live application

Here's the working demo of the application.

Use the following credentials to login:

2password: welcome

If the above credentials don't work, then create a sign up with a new user from the UI and login with those new credentials.

Setting up a new Rails application

Let's build a brand new Rails application. Rails offers us a command-line utility to build a brand new Rails application.

Run this command to generate a new Rails application with a specific Rails version:

1rails _7.0.3.1_ new granite --skip-turbolinks

It will produce a long output and might take some time to complete. It is downloading and setting up required files from the internet.

Setting a specific Webpacker version

First, we need to run the yarn install command to generate the Yarn lockfile, like so:

1yarn install

Remove the app/javascript directory as it has some unwanted files. When we install webpacker it will create the app/javascript folder with the required files.

Remove the app/javascript folder with the following command:

1rm -rf app/javascript

To install webpacker, add the webpacker gem towards the end of the file named Gemfile, like so:

1# For compiling and bundling JavaScript. Read more:
2gem "webpacker"

Run the following command from the terminal to install the newly added gem that is webpacker:

1bundle install

Now, we can setup the base for webpacker by running the following command from the terminal:

1bin/rails webpacker:install

Then, run the following command from the root of the project, in the terminal:

1yarn remove @rails/webpacker webpack-dev-server webpack webpack-cli
2yarn add @rails/webpacker@5.4.0
3yarn add -D webpack-dev-server@3.11.2 --exact

If you're curious about why we use a specific version of webpacker module, you can give the this section a read and come back. The webpack-dev-server package also needs to be a specific version that can work in conjunction with this Webpacker version. Else it will complain about installing webpack-cli.

Update to stylesheet pack tag

The default Rails application ERB template file, app/views/layout/application.html.erb, contains:

1<%= stylesheet_link_tag "application", "data-turbo-track": "reload" %>
2<%= javascript_importmap_tags %>

In that file, we need to replace stylesheet_link_tag with stylesheet_pack_tag and javascript_importmap_tags with javascript_pack_tag to attach CSS and JavaScript packs.

Thus update it like so:

1<%= stylesheet_pack_tag 'application' %>
2<%= javascript_pack_tag 'application' %>

We will discuss in depth about why we need to do this replacement towards the end of the book.

If you're very curious and don't mind the verbosity/complexity at this early stage itself, then you can give this section a read to understand about Webpacker's CSS compilation in depth.

Configuring default Ruby and Node.js versions

We can lock our application with a specific Ruby and Node.js version. This will help us to isolate the dependencies of Ruby and Node.js modules used in the application.

In our application we will use Node.js version 16.5 and Ruby version 3.0.4.

Run the following commands from the terminal:

1echo "16.5" > .nvmrc > .node-version
2echo "3.0.4" > .ruby-version

These files will be read by rbenv and nvm to auto-set the versions.

Now run the following commands from the terminal to ensure that our project is currently using these specified versions:

1rbenv install
2nvm install

The above commands should ideally point out that the specified versions are already installed and you can safely exit. If that's not the case, then please go ahead with the installation of the required versions, using the same commands.

Fixing rexml gem issue

We are not going to use some of the auto-generated gems for testing. Thus let's remove those unwanted gems, among which there are selenium based gems that may cause rexml dependency issue.

Run the following command from the terminal:

1bundle remove capybara selenium-webdriver webdrivers

The above command should've removed those unwanted gems from the Gemfile.

Remove unwanted gems

There are some gems that come pre installed in Rails 7 but are not required for our Granite application like importmap-rails, turbo-rails, and stimulus-rails.

Remove the following lines, including the comments, from the Gemfile:

1# Use JavaScript with ESM import maps []
2gem "importmap-rails"
4# Hotwire's SPA-like page accelerator []
5gem "turbo-rails"
7# Hotwire's modest JavaScript framework []
8gem "stimulus-rails"

Then update the Gemfile.lock file by running the following command:

1bundle install

Updating .gitignore file

We don't need all of the generated files to be version-controlled. To ignore these unwanted files, we specify them in the .gitignore file. BigBinary has specified a standard set of folders and files to be ignored by git in the Wheel repository.

Run the following command from the terminal, in the root of the project, to use that config:

1curl -o ".gitignore" ""

Now the .gitignore file should be visible in your project's root.

Removing fixtures

In a future chapter we will see why we are removing fixtures. For now let's just go ahead and disable the fixtures.

To disable using fixtures open test/test_helper.rb and comment out the line shown below.

1# fixtures :all

Execute the following lines on the terminal to delete the fixtures folder completely:

1rm -rf test/fixtures

Ensure fixtures wont get generated

Rails provide several generator commands that helps in generating boilerplate code for models, controllers, migration scripts, etc. We will be using them throughout the book.

But, with some of those generators, fixture files also get generated by default. We won't need those fixture files.

Fortunately, we can customize Rails generators to disable auto-generation of fixtures for all the commands.

To do that, add the following lines in config/application.rb:

1require_relative 'boot'
2require 'rails/all'
6module Granite
7  class Application < Rails::Application
8    # previous code if any
10    config.generators do |g|
11      g.test_framework :test_unit, fixture: false
12    end
13  end

For simple applications, we can always rely on using ActiveRecord queries to create seed data for tests instead of fixtures. We will learn about them in the upcoming chapters.

Creating database

SQlite3 database is the default database for a newly created Rails application.

Run this command to create databases for our application:

1bundle exec rails db:create

The output will look like this:

1Created database 'db/development.sqlite3'
2Created database 'db/test.sqlite3'

Starting the server

Now let's start the server. Run this command:

1bundle exec rails server

The output would look like this:

1=> Booting Puma
2=> Rails 7.0.4 application starting in development
3=> Run `bin/rails server --help` for more startup options
4Puma starting in single mode...
5* Puma version: 5.6.5 (ruby 3.0.4-p208) ("Birdie's Version")
6*  Min threads: 5
7*  Max threads: 5
8*  Environment: development
9*          PID: 16385
10* Listening on
11* Listening on http://[::1]:3000
12Use Ctrl-C to stop

Open browser and visit http://localhost:3000. We will see a page that would look like this: Rails new project landing page

Verify Ruby and NodeJS versions

Before committing the files, let's verify whether our Ruby and Node.js versions are the required versions or not, by running the following commands from terminal:

1rbenv version # should be 3.0.4
2nvm version # should be 16.5

Also from the root of the project run the following command to double verify that Ruby is set to required version:

1ruby -v # should be 3.0.4

Another final point of verification is the version line in the Gemfile, which can be found at the root of the project. The following line with required version should be present within the Gemfile:

1ruby "3.0.4"

If the Ruby version is not matching the rbenv set version, then it means that there is a system level Ruby version that is taking precedence. In that case, you'd have to set the Ruby version globally as mentioned in the previous chapter.

Once verified, add this new application to git:

1git add -A
2git commit -m "Initial commit"
3git rm -r --cached . # to reapply gitignore
4git add -A
5git commit -m "Applied gitignore"