# React on Rails Basic Tutorial

_Also see the example repo of [React on Rails Tutorial With SSR, HMR fast refresh, and TypeScript](https://github.com/shakacode/react_on_rails_demo_ssr_hmr)_ 

-----

*Updated for Ruby 2.7, Rails 7, React on Rails v13, and Shakapacker v6*

This tutorial guides you through setting up a new or existing Rails app with **React on Rails**, demonstrating Rails + React + Redux + Server Rendering.

After finishing this tutorial you will get an application that can do the following (live on Heroku):

![example](https://cloud.githubusercontent.com/assets/371302/17368567/111cc722-596b-11e6-9b72-ac5967a60e42.gif)

You can find it here:
* [Source code for this app in PR, using the --redux option](https://github.com/shakacode/react_on_rails-test-new-redux-generation/pull/17) and [for Heroku](https://github.com/shakacode/react_on_rails-test-new-redux-generation/pull/18).
* [Live on Heroku](https://react-on-rails-redux-gen-8-0-0.herokuapp.com/)

By the time you read this, the latest may have changed. Be sure to check the versions here:

* https://rubygems.org/gems/react_on_rails
* https://www.npmjs.com/package/react-on-rails

# Table of Content:
- [Installation](#installation)
  - [Setting up your environment](#setting-up-your-environment)
  - [Create a new Ruby on Rails App](#create-a-new-ruby-on-rails-app)
  - [Add the shakapacker and react_on_rails gems](#add-the-shakapacker-and-react_on_rails-gems)
  - [Run the shakapacker (webpacker) generator](#run-the-shakapacker-webpacker-generator)
  - [Run the React on Rails Generator](#run-the-react-on-rails-generator)
  - [Setting up your environment variables](#setting-up-your-environment-variables)
  - [Running the app](#running-the-app)
- [HMR vs. React Hot Reloading](#hmr-vs-react-hot-reloading)
- [Deploying to Heroku](#deploying-to-heroku)
  - [Create Your Heroku App](#create-your-heroku-app)
  - [Swap out sqlite for postgres](#swap-out-sqlite-for-postgres)
- [Other features](#other-features)
  - [Turning on Server Rendering](#turning-on-server-rendering)
  - [Moving from the Rails default `/app/javascript` to the recommended `/client` structure](#moving-from-the-rails-default-appjavascript-to-the-recommended-client-structure)
  - [Using HMR with the shakapacker setup](#using-hmr-with-the-railswebpacker-setup)
  - [Custom IP & PORT setup (Cloud9 example)](#custom-ip--port-setup-cloud9-example)
  - [RubyMine performance tip](#rubymine-performance-tip)
- [Conclusion](#conclusion)
# Installation
## Setting up your environment

Trying out **React on Rails** is super easy, so long as you have the basic prerequisites.

- **Ruby:** We support all active Ruby versions but recommend using the latest stable Ruby version. Solutions like [rvm](https://rvm.io) or [rbenv](https://github.com/rbenv/rbenv) make it easy to have multiple Ruby versions on your machine.
- **Rails:** We support Rails 6 and later.
- **Nodejs:** We support all [active Node versions](https://github.com/nodejs/release#release-schedule) but recommend using the latest LTS release of Nodejs for the longest support. Older inactive node versions might still work but is not guaranteed. We also recommend using [nvm](https://github.com/nvm-sh/nvm/) to ease using different node versions in different projects.
- **yarn:** We use [yarn classic](https://classic.yarnpkg.com/) as our node package manager.
- You need to have either [Overmind](https://github.com/DarthSim/overmind) or [Foreman](https://rubygems.org/gems/foreman) as a process manager.

## Create a new Ruby on Rails App
Then we need to create a fresh Rails application as follows.

First, be sure to run `rails -v` and check you are using Rails 5.1.3 or above. If you are using an older version of Rails, you'll need to install webpacker with react per the instructions [here](https://github.com/rails/webpacker).

```bash
# For Rails 6.x
rails new test-react-on-rails --skip-javascript

# For Rails 7.x
rails new test-react-on-rails --skip-javascript

cd test-react-on-rails
```
Note: You can use `--database=postgresql` option to use Postgresql for the database.

## Add the shakapacker and react_on_rails gems
We recommend using the latest version of these gems. Otherwise, specify the
exact versions of both the gem and npm packages. In other words, don't use
the `^` or `~` in the version specifications.

```bash
bundle add react_on_rails --strict
bundle add shakapacker --strict
```

Note: The latest released React On Rails version is considered stable. Please use the latest
version to ensure you get all the security patches and the best support.

## Run the shakapacker (webpacker) generator

```bash
bundle exec rails webpacker:install
```

Commit all the changes so far to avoid getting errors in the next step.

```bash
git commit -am "Initial commit"
```

Alternatively, you can use `--ignore-warnings` in the next step.

## Run the React on Rails Generator

```bash
rails generate react_on_rails:install
```

You will be prompted to approve changes in certain files. Press `enter` to proceed
one by one or enter `a` to replace all configuration files required by the project.
You can check the diffs before you commit to see what changed.

Note, using `redux` is no longer recommended as the basic installer uses React Hooks.
If you want the redux install, run:

```bash
rails generate react_on_rails:install --redux
```

## Setting up your environment variables

Add the following variable to your environment:

```
EXECJS_RUNTIME=Node
```

Then run the server with one of the following options:

## Running the app

```bash
./bin/dev # For HMR
# or
./bin/dev-static # Without HMR, statically creating the bundles
```

Visit [http://localhost:3000/hello_world](http://localhost:3000/hello_world) and see your **React On Rails** app running!

# HMR vs. React Hot Reloading

First, check that the `hmr` and the `inline` options are `true` in your `config/webpacker.yml` file.

The basic setup will have HMR working with the default Shakapacker setup. The basic
[HMR](https://webpack.js.org/concepts/hot-module-replacement/), without a special
React setup, will cause a full page refresh each time you save a file.

# Deploying to Heroku

## Create Your Heroku App
*Assuming you can log in to heroku.com and have logged into your shell for Heroku.*

1. Visit [https://dashboard.heroku.com/new](https://dashboard.heroku.com/new) and create an app, say named `my-name-react-on-rails`:

![06](https://cloud.githubusercontent.com/assets/20628911/17465014/1f29bf3c-5cf4-11e6-869f-4215987ae854.png)

Run this command that looks like this from your new Heroku app

```bash
heroku git:remote -a my-name-react-on-rails
```

Set heroku to use multiple buildpacks:

```bash
heroku buildpacks:set heroku/ruby
heroku buildpacks:add --index 1 heroku/nodejs
```

## Swap out sqlite for postgres:
Heroku requires your app to use Postgresql. If you have not setup your app
with Postgresql, you need to change your app settings to use this database.

Run the following command (in Rails 6+):

```bash
rails db:system:change --to=postgresql
```

If for any reason you want to do this process manually, run these two commands:

```bash
bundle remove sqlite3
bundle add pg
```

![07](https://cloud.githubusercontent.com/assets/20628911/17465015/1f2f4042-5cf4-11e6-8287-2fb077550809.png)

Now replace your `database.yml` file with this (assuming your app name is "ror").

```yml
default: &default
  adapter: postgresql
  username:
  password:
  host: localhost

development:
  <<: *default
  database: ror_development

# Warning: The database defined as "test" will be erased and
# re-generated from your development database when you run "rake".
# Do not set this db to the same as development or production.
test:
  <<: *default
  database: ror_test

production:
  <<: *default
  database: ror_production
```

Then you need to setup postgres so you can run locally:

```bash
rake db:setup
rake db:migrate
```

![08](https://cloud.githubusercontent.com/assets/20628911/17465016/1f3559f0-5cf4-11e6-8ab4-c5572e4644a5.png)

Optionally you can add this line to your `routes.rb`. That way, your root page will go to the Hello World page for React On Rails.

```ruby
root "hello_world#index"
```

![09](https://cloud.githubusercontent.com/assets/20628911/17465018/1f3b685e-5cf4-11e6-93f8-105fc48517d0.png)

Next, configure your app for Puma, per the [instructions on Heroku](https://devcenter.heroku.com/articles/deploying-rails-applications-with-the-puma-web-server).

Create `./Procfile` with the following content. This is what Heroku uses to start your app.

```
web: bundle exec puma -C config/puma.rb
```

Note, newer versions of Rails create this file automatically. However, the [docs on Heroku](https://devcenter.heroku.com/articles/deploying-rails-applications-with-the-puma-web-server#config) have something a bit different, so please make it conform to those docs. As of 2020-06-04, the docs looked like this:

`config/puma.rb`
```rb
workers Integer(ENV['WEB_CONCURRENCY'] || 2)
threads_count = Integer(ENV['RAILS_MAX_THREADS'] || 5)
threads threads_count, threads_count

preload_app!

rackup      DefaultRackup
port        ENV['PORT']     || 3000
environment ENV['RACK_ENV'] || 'development'

on_worker_boot do
  # Worker specific setup for Rails 4.1+
  # See: https://devcenter.heroku.com/articles/deploying-rails-applications-with-the-puma-web-server#on-worker-boot
  ActiveRecord::Base.establish_connection
end
```

Next, update your `package.json` to specify the version of yarn and node. Add this section:

```json
  "engines": {
    "node": "16.19.0",
    "yarn": "1.22.4"
  },
```

Then after all changes are done don't forget to commit them with git and finally, you can push your app to Heroku!

```bash
git add -A
git commit -m "Changes for Heroku"
git push heroku master
```

Then run:

```bash
heroku open
```

and you will see your live app and you can share this URL with your friends. Congrats!

# Other features
## Turning on Server Rendering

You can turn on server rendering by simply changing the `prerender` option to `true`:

```erb
<%= react_component("HelloWorld", props: @hello_world_props, prerender: true) %>
```

If you want to test this out with HMR, then you also need to add this line to your
`config/intializers/react_on_rails.rb`

```ruby
  config.same_bundle_for_client_and_server = true
```

More likely, you will create a different build file for server rendering. However, if you want to
use the same file from the webpack-dev-server, you'll need to add that line.

When you look at the source code for the page (right click, view source in Chrome), you can see the difference between non-server rendering, where your DIV containing your React looks like this:

```html
<div id="HelloWorld-react-component-b7ae1dc6-396c-411d-886a-269633b3f604"></div>
```

versus with server rendering:

```html
<div id="HelloWorld-react-component-d846ce53-3b82-4c4a-8f32-ffc347c8444a"><div data-reactroot=""><h3>Hello, <!-- -->Stranger<!-- -->!</h3><hr/><form><label for="name">Say hello to:</label><input type="text" id="name" value="Stranger"/></form></div></div>
```

For more details on server rendering, see:

  + [Client vs. Server Rendering](https://www.shakacode.com/react-on-rails/docs/guides/client-vs-server-rendering/)
  + [React Server Rendering](https://www.shakacode.com/react-on-rails/docs/guides/react-server-rendering/)

## Moving from the Rails default `/app/javascript` to the recommended `/client` structure

ShakaCode recommends that you use `/client` for your client side app. This way a non-Rails, front-end developer can be at home just by opening up the `/client` directory.


1. Move the directory:

```bash
mv app/javascript client
```

2. Edit your `/config/webpacker.yml` file. Change the `default/source_path`:

```yml
source_path: client
```

## Using HMR with the shakapacker setup

Start the app using `overmind start -f Procfile.dev` or `foreman start -f Procfile.dev`.

When you change and save a JSX file, the browser will automatically refresh!

So you get some basics from HMR with no code changes. If you want to go further, take a look at these links:

* [webpack-dev-server](https://github.com/rails/webpacker/blob/5-x-stable/docs/webpack-dev-server.md)
* [DevServer](https://webpack.js.org/configuration/dev-server/)
* [Hot Module Replacement](https://webpack.js.org/concepts/hot-module-replacement/)

React on Rails will automatically handle disabling server rendering if there is only one bundle file created by the Webpack development server by `shakapcker`.


## Custom IP & PORT setup (Cloud9 example)

In case you are running some custom setup with different IP or PORT you should also edit Procfile.dev. For example, to be able to run on free Cloud9 IDE we are putting IP 0.0.0.0 and PORT 8080. The default generated file `Procfile.dev` uses `-p 3000`.

``` Procfile.dev
web: rails s -p 8080 -b 0.0.0.0
```

Then visit https://your-shared-addr.c9users.io:8080/hello_world

## RubyMine performance tip

It's super important to exclude certain directories from RubyMine or else it will slow to a crawl as it tries to parse all the npm files.

* Generated files, per the settings in your `config/webpacker.yml`, which default to `public/packs` and `public/packs-test`
* `node_modules`




# Conclusion

* Browse the docs on [our documentation website](https://www.shakacode.com/react-on-rails/docs/)

Feedback is greatly appreciated! As are stars on github!

If you want personalized help, don't hesitate to get in touch with us at [contact@shakacode.com](mailto:contact@shakacode.com). We offer [React on Rails Pro](https://github.com/shakacode/react_on_rails/wiki) and consulting so you can focus on your app and not on how to make Webpack plus Rails work optimally.