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Rails-API-React-Tutorial 💻

Hey! This is a super-easy to follow Rails/React API tutorial that is fully in depth from start to finish. This guide shows you how to install a Ruby on Rails 6 API with React JS via Webpacker and connecting the frontend with the backend.

Stack: Rails 6 API + React JS located in app/javascript + Webpacker

System Requirements

ruby "2.6.3" +

gem "rails", "~> 6.1.3"

Creating a Rails API
Rails API Versioning
React Integration
Restructure our React Project
Our First Component
Rails Serializers
Contributing
About the Author

Rails API 💎

The new rails api command scaffolds everything we need to get up and ready for our project. Let's start our rails server and being integrating the backend first.

Run the following: rails new my_app -T --database=postgresql

What's going on here? The -T command also tells rails that we don't want Minitest as our testing suite. You'll most likely be used to Rspec so we'll talk about that later in the guide. The --database=postgresql line is pretty much self explanatory!

Rails API Versioning

Versioning is the process of seperating and creating new features/data/endpoints for your API. Since this is our first API, let's make our rails api v1.

Run the following in your terminal

mkdir app/controllers/api && mkdir app/controllers/api/v1

Now that our versioning is complete, let's test out a model and controller to work with our new url of localhost:3000/api/v1.

Let's scaffold a test model/controller and call it movies

rails g scaffold Movies name:string rating:integer

Don't forget to rails db:create if it was not yet initialized!

Then we can use rails db:migrate for our scaffold.

The Rails engine creates your controller in the default /controllers directory but we need to move our new controller into the api/v1 directory.

You can either move it manually or the following:

mv app/controllers/movies_controller.rb app/controllers/api/v1

Update the Movies Controller

Our newly generated controller does not properly inherit from the namespace api/v1 (We will update the routes later in the tutorial) so let's change our controller class from

class MoviesController < ApplicationController

module Api
  module V1
    class MoviesController < ApplicationController
    # The scaffold ruby code is here~
    end
  end
end

This makes it so we can INHERIT from the application controller without any additional tinkering.

Update the Routes Locate to your config folder and open your routes.rb file.

Rails.application.routes.draw do
  resources :movies
end

If we go to localhost:3000/movies we will not call the controller. We must update our Routes to:

Rails.application.routes.draw do
 namespace :api do
  namespace :v1 do
   resources :movies
  end
 end
end

which allows us to call the json data from localhost:3000/api/v1/movies

Let's seed our PG database with some classic movies so we can practice getting data with GET requests to the API.

Copy and paste the following data to your db/seeds.rb file.

Movie.create(name: "The Nightmare Before Christmas", rating: 5)
Movie.create(name: "Titanic", rating: 5)
Movie.create(name: "Venom", rating: 4)
Movie.create(name: "A Quiet Place", rating: 5)
Movie.create(name: "Nobody's Fool", rating: 2)
Movie.create(name: "Suspiria", rating: 4)
Movie.create(name: "Hereditary", rating: 4)
Movie.create(name: "Office Space", rating: 5)
Movie.create(name: "Elf", rating: 4)
Movie.create(name: "Dawn of the Planet of the Apes", rating: 3)
Movie.create(name: "Secret life of Pets", rating: 4)
Movie.create(name: "Overlord", rating: 3)
Movie.create(name: "Wonder Woman", rating: 5)
Movie.create(name: "Bohemian Rhapsody", rating: 4)
Movie.create(name: "Ocean's 8", rating: 5)

Seed the DB using rails db:seed.

Test the API using a GET request.

Start your Rails server rails s or rails s -b 0.0.0.0 and navigate to localhost:3000/api/v1/movies and if it is successful you should see the following JSON output: <img src="https://i.ibb.co/KXPQ1cd/Screen-Shot-2021-04-06-at-12-58-12-PM.png" /> (Optional) I'm using a pretty JSON viewer for chrome which you can download.

Congrats! You have successfully created a Rails API and completed your first GET request!

React Integration

React is a component based front end framework that makes it easy to make frontend calls to our Rails API. Let's make this organized as possible and add our react directory inside our rails app/javascript directory.

Open your terminal and run the following webpacker commands to init the React Process.

bundle exec rails webpacker:install:react

And wait for the Webpacker now supports react.js 🎉 message to finally use React! Woah :)

Locate the javascript directory inside /app and see the new file we have with React.

Note: Notice the H1 tag on the Hello {props.name}!, this is so we can see it clearly. When intalling, the H1 tag will not be there. It is purely cosmetic for now.

# app/javascript/packs/hello_react.jsx
import React from 'react'
import ReactDOM from 'react-dom'
import PropTypes from 'prop-types'

const Hello = props => (
  <div><h1>Hello {props.name}!</h1></div>
)

Hello.defaultProps = {
  name: 'David'
}

Hello.propTypes = {
  name: PropTypes.string
}

document.addEventListener('DOMContentLoaded', () => {
  ReactDOM.render(
    <Hello name="React" />,
    document.body.appendChild(document.createElement('div')),
  )
})

We can hook this file into any view we want React to send, so lets try this out now and add this to a demo view.

Let's create a Home controller + view so can we load React to it. Run the following

rails g controller Home index

and locate your routes in config/routes.rb

Open the route file and ROOT your application to the home controller

Rails.application.routes.draw do
  root 'home#index'
  # For details on the DSL available within this file, see https://guides.rubyonrails.org/routing.html
end

We now need to load our hello_react.jsx file to the HOME view, so let's include that now.

<%= javascript_pack_tag "hello_react" %>

Run the rails server, and check out the React magic at hand! YAHOO!!

React has been linked, successfully.

Restructure our React Project

Personally, I don't like the structure of React in this concept, so let's add something more "neater" so we can find our components easier.

Delete all of the contents inside the javascript directory so we can start fresh.
Create 2 new folders named components and packs inside the javascript folder.
Inside your packs folder, create a file named application.js and add the following to it:

import Rails from "@rails/ujs"
import Turbolinks from "turbolinks"
import * as ActiveStorage from "@rails/activestorage"

Rails.start()
Turbolinks.start()
ActiveStorage.start()

Let's also create a hello_react.jsx file and add the following:

import React from 'react'
import ReactDOM from 'react-dom'
import App from '../components/App'

document.addEventListener('DOMContentLoaded', () => {
  ReactDOM.render(
    <App />,
    document.body.appendChild(document.createElement('div')),
  )
})

Next, let's create a new folder named components and create a file named App.js

Add the following to App.js

import React, { Component } from 'react'

class App extends Component {
  render(){
    return(
      <div>
      <h1> React says Hello! </h1>
      </div>

    )
  }
}

export default App

You should now be able to see the structure better with a components folder and add any new component you wish!. Let's run the rails server to see if its calling our new H1 text.

Our new structure is complete! You can stop here and make your own API to your own liking. In the next section, we can create a new component and test the data being called!

Our First Component

React JS is all about components! Assuming we know basic React workflow, lets create a new component under the component direct named MovieInfo.js

We can add the following to MovieInfo.js as the basic skeleton.

# app/js/components/MovieInfo.js

import React from 'react'

export class MovieInfo extends React.Component {

  constructor() {
     super();
   }

  render() {
    return (
      <div>
      </div>
  )
}

}
export default MovieInfo;

Let us add a state method so we can fill the array with the API call. Add this under the export class line

  constructor() {
     super();
     this.state = {
       movies: []
     };
   }

We should ass add the componentDidMount function so the data can be created in the virtual DOM on page load.

  componentDidMount(){
    fetch("/api/v1/movies")
    .then(resp => resp.json())
    .then(m => {
      this.setState({
        movies: m
      })
    })
    .catch(error => console.log(error))
  }

Our final file should look like this.

import React from 'react'

export class MovieInfo extends React.Component {

  constructor() {
     super();
     this.state = {
       movies: []
     };
   }

  componentDidMount(){
    fetch("/api/v1/movies")
    .then(resp => resp.json())
    .then(a => {
      this.setState({
        movies: a
      })
    })
    .catch(error => console.log(error))
  }

  render() {
    return (
      <div>
      {this.state.movies.map(obj =>
        <p key={obj.id}>{obj.name}</p>

      )}
     </div>
  )
}

}
export default MovieInfo;

Import the file to our App.js file.

import React, { Component } from 'react'
// Here V
import MovieInfo from './MovieInfo'.


class App extends Component {
  render(){
    return(
      <div>
      // And Here V
        <MovieInfo />
      </div>

    )
  }
}

export default App

Start the rails server! And Success!! We can now make API calls to our backend! <img src="https://i.ibb.co/ys2SQFd/Screen-Shot-2021-04-09-at-3-47-16-PM.png" width="300" alt="Screen-Shot-2021-04-09-at-3-47-16-PM" border="0">

💘💘💘💘💘💘💘💘💘💘💘💘💘💘💘💘💘💘💘💘💘💘💘💘💘💘💘💘💘💘💘💘💘💘💘💘 Congratulations! Our Rails API and React Client is done! If you enjoyed this API tutorial please give it a star and share it with your friends!

Rails Serializers

What are Serializers? Well Rails API's returns JSON data in full, so serializers allows us to cherry pick the exact data we want in a much organized fashion. Instead of getting every column from the returned data, we can grab which ever we allow to pass through.

Normal Model	Serializer Model
id, name, rating, director, score, actors_id, created_at, updated_at	id, name, rating

We are able to tell the Rails API what to fetch rather than the frontend; making it much more simple and faster to scaffold your next project.

Installation

Open your gemfile and add the serializer gem into your project. Don't forget to bundle install !

# Serializer
gem 'active_model_serializers', '~> 0.10.0'

We want to create a clone of any current model we have so when we make requests in the backend, the request will read the serializer file first, then it will find the rails model/controller to finisht the request. We have a model called Movie so we'll duplicate that by running:

rails g serializer movie

You can see that a new directory was made in the app/ directory and we now have app/serializers/movie_serializer file in our project.

Let's open that file and see what we have:

class MovieSerializer < ActiveModel::Serializer
  attributes :id, :name, :rating
end

We have our Movie Class inheriting from the serializer class on the first line, and the returned attribute on the second. So far the default returned attribute is just an ID, a name, and a rating.

1a. Turn on your rails server and go to the url localhost:3000/api/v1/movies

You should see that only the id and name attribute is being returned from the database.


{ "movies":
        [
          {
            "id": 1,
            "name": "The Nightmare Before Christmas",
            "rating": 5
          },
          {
            "id": 2,
            "name": "The Titanic",
            "rating": 5
          },
          {
            "id": 3,
            "name": "Venom",
            "rating": 4
          }
        ]
 }

We are done! What is the takeaway? React will be fetching a lot of JSON data and we can reduce the uneeded attributes like created_at or updated_at that does not need to be displayed on the page.

Contributing

Fork it
Create your feature branch (git checkout -b my-new-feature)
Commit your changes (git commit -am 'Add some feature')
Push to the branch (git push origin my-new-feature)
Create new Pull Request

I love collaboration! Please feel free to contribute or add your insights ✨

About the Author

Blog @jc · GitHub @johncorderox ·