How to create a Rails + Hotwire website

You only need the first 7 steps, the rest is extra info.

This guide is written for Unix systems. If you're using Windows, get help

btw this website uses Hotwire and you can get the code on GitLab.

Install Ruby and Rails

Use rvm. In your terminal, run:

\curl -sSL https://get.rvm.io | bash -s stable --rails

Create a new Rails project

rails new your-project-name --database=sqlite3

And cd into it (cd your-project-name).

The database is optional (you can leave out --database=sqlite3) and you can add it later.

Install packages

bundle install

If you added a database before, create it

bin/rails db:create

Set up JavaScript module imports

bin/rails importmap:install

Accept all overwrites.

Create some pages and controllers for them

I'll create home, posts and contact.

bin/rails generate controller Pages home posts contact

Controllers are for backend logic that runs on your server and not in the browser. You probably don't need a controller for most pages so you can leave out the controller part.

You can add more pages and controllers later with the same command.

Run the server

bin/rails server

If everything works, the setup is done and you can start coding.

Where to write your code

Your pages are in app/views/pages/ in files like example.html.erb. These are "Embedded Ruby" files, you can write Ruby and HTML in here and they will be rendered into pure HTML when served. You could also write CSS and JavaScript in here but you should use a global stylesheet and separate your JS into controllers, that's how Hotwire was intended to be used.

Take a look inside config/routes.rb - this is where the routing is defined. The generate command we ran before already set up routes for our pages, but you can change it.

Global CSS

To change global styles, edit app/assets/stylesheets/application.css

Adding Ruby code

You should write Ruby code inside the controller files in app/controllers/ or in helper files in app/helpers/. The Ruby code is executed on the server so you should do sensitive operations here.

Controllers handle the business logic and the flow of data, e.g. handling form submissions, updating the database or rendering UI. Their names must end with _controller.rb.

Helpers are for organizing and simplifying the logic used in views, e.g. formatting data or making some calculations. Their names must end with _helper.rb.

Here's an example of using some computed data:

Edit app/helpers/application_helpers.rb. This is available throughout your app. Use this code to get the current data:

module ApplicationHelper
  def current_date_example
    Date.today.to_s
  end
end

Then edit app/views/pages/home.html.erb and add this:

<p><%= current_date_example %></p>

Restart your server.

Now when you visit your homepage (at /) you will see the current date.

Of course, you could also inline that and skip the helper:

<p><%= Date.today.to_s %></p>

Adding JavaScript code

Hotwire uses a JavaScript framework called Stimulus. The JS code is executed in the client browser so you shouldn't do sensitive operations here.

To write a script, create a controller file in app/javascript/controllers/ and call it example_controller.js. It needs the _controller at the end of the name.

Then attach the controller to an element in your HTML using the data-controller attribute, like this:

<div data-controller="example">...</div>

"example" should match the controller name (in example_controller.js) so that Stimulus can attach it.

Now add some code to your controller. Inside example_controller.js, use this structure:

import { Controller } from "@hotwired/stimulus";

export default class extends Controller {
  connect() {
    // Code inside connect() runs when the attached HTML element first loads
    example();
  }

  disconnect() {
    // Code inside disconnect() runs when the element unloads
  }

  // You can write your functions here and call them in connect() or disconnect()
  sayHi() {
    console.log("Hi");
  }
}

For more details, read the official docs: Stimulus Controllers

Adding a database after setup

If you didn't add a database during initial setup, here's how you can add it afterwards.

Add SQLite3 to your Gemfile by adding this line

gem 'sqlite3'

Install the gem. In your terminal from inside your project, run

bundle install

Generate the database

bin/rails db:create

Run migrations to set up the schema

rails db:migrate

Notes

The app will automatically show changes when you edit your .html.erb files. But if you make changes to other files, then you need to restart your server — you can stop it with ctrl+c and then run bin/rails server again.

For some changes, e.g. CSS files, JS files or adding new dependencies, you should also clean out precompiled and cached assets and generate new ones, like this:

bin/rails assets:clobber && bin/rails assets:precompile

Hosting your app

If you want to host your Hotwire app somewhere, read this.

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