How to Wire Up Ruby on Rails and AngularJS as a Single-Page Application (Updated for 2016)

by Jason Swett,
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Refreshed for 2016

I wrote my first Angular/Rails tutorial in 2014, then another one in 2015. My 2015 post used CoffeeScript. CoffeeScript, from my perspective, is probably not going to play a large role in the future of JavaScript. Angular 2 uses TypeScript by default. TypeScript is a superset of ES6, so if you’re using ES6 in an Angular app, that will presumably make it easier to upgrade to Angular 2/TypeScript than if you’re using CoffeeScript. So I think it makes more sense at this point in time for me to use ES6 than CoffeeScript for my tutorial.

My 2015 post has also not shockingly suffered from a little bit of software rot as the world has moved forward while it has stood still. If you follow it character-for-character today, it doesn’t work. I thought it would be nice to put out a new tutorial that actually works.

The sample app

There’s a certain sample app I plan to use throughout AngularOnRails.com called Lunch Hub. The idea with Lunch Hub is that office workers can announce in the AM where they’d like to go for lunch rather than deciding as they gather around the door and waste half their lunch break. Since Lunch Hub is a real project with its own actual production code, I use a different project here called “Fake Lunch Hub.” You can see the Fake Lunch Hub repo here.

Setting up our Rails project

Instead of regular Rails we’re going to use Rails::API. I’ve tried to do Angular projects with full-blown Rails, but I end up with a bunch of unused views, which feels weird. First, if you haven’t already, install Rails::API. (Side note: I realize that Rails 5 offers an API-only version. Rails 5 is still in beta and I want you to be able to use this tutorial as a starting point for production projects, so I’m using Rails::API 4.2.x for this tutorial.)

$ gem install rails-api

Creating a new Rails::API project works the same as creating a regular Rails project.

$ rails-api new fake_lunch_hub -T -d postgresql

Get into our project directory.

$ cd fake_lunch_hub

Create our PostgreSQL user.

$ createuser -P -s -e fake_lunch_hub

Create the database.

$ rake db:create

Now we’ll create a resource so we have something to look at through our AngularJS app. (This might be a good time to commit this project to version control.)

Creating our first resource

Add gem 'rspec-rails' to your Gemfile (in the test group) and run:

$ bundle install
$ rails g rspec:install

When you generate scaffolds from now on, RSpec will want to create all kinds of spec files for you automatically, including some kinds of specs (like view specs) that in my opinion are kind of nutty and really shouldn’t be there. We can tell RSpec not to create these spec files:

require File.expand_path('../boot', __FILE__)

# Pick the frameworks you want:
require "active_model/railtie"
require "active_record/railtie"
require "action_controller/railtie"
require "action_mailer/railtie"
require "action_view/railtie"
require "sprockets/railtie"
# require "rails/test_unit/railtie"

# Require the gems listed in Gemfile, including any gems
# you've limited to :test, :development, or :production.
Bundler.require(*Rails.groups)

module FakeLunchHub
  class Application < Rails::Application
    # Settings in config/environments/* take precedence over those specified here.
    # Application configuration should go into files in config/initializers
    # -- all .rb files in that directory are automatically loaded.

    # Set Time.zone default to the specified zone and make Active Record auto-convert to this zone.
    # Run "rake -D time" for a list of tasks for finding time zone names. Default is UTC.
    # config.time_zone = 'Central Time (US & Canada)'

    # The default locale is :en and all translations from config/locales/*.rb,yml are auto loaded.
    # config.i18n.load_path += Dir[Rails.root.join('my', 'locales', '*.{rb,yml}').to_s]
    # config.i18n.default_locale = :de

    config.generators do |g|
      g.test_framework :rspec,
        fixtures: false,
        view_specs: false,
        helper_specs: false,
        routing_specs: false,
        request_specs: false,
        controller_specs: true
    end
  end
end

(Now might be another good time to make a commit.)

In Lunch Hub, I want everybody’s lunch announcements to be visible only to other people in the office where they work, not the whole world. And there’s actually a good chance a person might want to belong not only to a group tied to his or her current workplace, but perhaps a former workplace or totally arbitrary group of friends. So I decided to create the concept of a Group in Lunch Hub. Let’s create a Group resource that, for simplicity, has only one attribute: name.

$ rails g scaffold group name:string

Since groups have to have names, let’s set null: false in the migration. We’ll also include a uniqueness index.

class CreateGroups < ActiveRecord::Migration
  def change
    create_table :groups do |t|
      t.string :name, null: false

      t.timestamps
    end

    add_index :groups, :name, unique: true
  end
end
$ rake db:migrate

Now, if you run rails server and go to http://localhost:3000/groups, you should see empty brackets ([]). We actually want to be able to do http://localhost:3000/api/groups instead.

Rails.application.routes.draw do
  scope '/api' do
    resources :groups, except: [:new, :edit]
  end
end

At the risk of being annoying, I wanted to include a realistic level of testing in the tutorial, at least on the server side.

require 'rails_helper'

RSpec.describe Group, :type => :model do
  before do
    @group = Group.new(name: "Ben Franklin Labs")
  end

  subject { @group }

  describe "when name is not present" do
    before { @group.name = " " }
    it { should_not be_valid }
  end
end

To make this spec pass you’ll of course need to add a validation:

class Group < ActiveRecord::Base
  validates :name, presence: true
end

We also have to adjust the controller spec RSpec spit out for us because RSpec’s generators are evidently not yet fully compatible with Rails::API. The generated spec contains an example for the `new` action, even though we don’t have a `new` action. You can remove that example yourself or you can just copy and paste my whole file.

require 'rails_helper'

# This spec was generated by rspec-rails when you ran the scaffold generator.
# It demonstrates how one might use RSpec to specify the controller code that
# was generated by Rails when you ran the scaffold generator.
#
# It assumes that the implementation code is generated by the rails scaffold
# generator.  If you are using any extension libraries to generate different
# controller code, this generated spec may or may not pass.
#
# It only uses APIs available in rails and/or rspec-rails.  There are a number
# of tools you can use to make these specs even more expressive, but we're
# sticking to rails and rspec-rails APIs to keep things simple and stable.
#
# Compared to earlier versions of this generator, there is very limited use of
# stubs and message expectations in this spec.  Stubs are only used when there
# is no simpler way to get a handle on the object needed for the example.
# Message expectations are only used when there is no simpler way to specify
# that an instance is receiving a specific message.

RSpec.describe GroupsController, :type => :controller do

  # This should return the minimal set of attributes required to create a valid
  # Group. As you add validations to Group, be sure to
  # adjust the attributes here as well.
  let(:valid_attributes) {
    skip("Add a hash of attributes valid for your model")
  }

  let(:invalid_attributes) {
    skip("Add a hash of attributes invalid for your model")
  }

  # This should return the minimal set of values that should be in the session
  # in order to pass any filters (e.g. authentication) defined in
  # GroupsController. Be sure to keep this updated too.
  let(:valid_session) { {} }

  describe "GET index" do
    it "assigns all groups as @groups" do
      group = Group.create! valid_attributes
      get :index, {}, valid_session
      expect(assigns(:groups)).to eq([group])
    end
  end

  describe "GET show" do
    it "assigns the requested group as @group" do
      group = Group.create! valid_attributes
      get :show, {:id => group.to_param}, valid_session
      expect(assigns(:group)).to eq(group)
    end
  end

  describe "GET edit" do
    it "assigns the requested group as @group" do
      group = Group.create! valid_attributes
      get :edit, {:id => group.to_param}, valid_session
      expect(assigns(:group)).to eq(group)
    end
  end

  describe "POST create" do
    describe "with valid params" do
      it "creates a new Group" do
        expect {
          post :create, {:group => valid_attributes}, valid_session
        }.to change(Group, :count).by(1)
      end

      it "assigns a newly created group as @group" do
        post :create, {:group => valid_attributes}, valid_session
        expect(assigns(:group)).to be_a(Group)
        expect(assigns(:group)).to be_persisted
      end

      it "redirects to the created group" do
        post :create, {:group => valid_attributes}, valid_session
        expect(response).to redirect_to(Group.last)
      end
    end

    describe "with invalid params" do
      it "assigns a newly created but unsaved group as @group" do
        post :create, {:group => invalid_attributes}, valid_session
        expect(assigns(:group)).to be_a_new(Group)
      end

      it "re-renders the 'new' template" do
        post :create, {:group => invalid_attributes}, valid_session
        expect(response).to render_template("new")
      end
    end
  end

  describe "PUT update" do
    describe "with valid params" do
      let(:new_attributes) {
        skip("Add a hash of attributes valid for your model")
      }

      it "updates the requested group" do
        group = Group.create! valid_attributes
        put :update, {:id => group.to_param, :group => new_attributes}, valid_session
        group.reload
        skip("Add assertions for updated state")
      end

      it "assigns the requested group as @group" do
        group = Group.create! valid_attributes
        put :update, {:id => group.to_param, :group => valid_attributes}, valid_session
        expect(assigns(:group)).to eq(group)
      end

      it "redirects to the group" do
        group = Group.create! valid_attributes
        put :update, {:id => group.to_param, :group => valid_attributes}, valid_session
        expect(response).to redirect_to(group)
      end
    end

    describe "with invalid params" do
      it "assigns the group as @group" do
        group = Group.create! valid_attributes
        put :update, {:id => group.to_param, :group => invalid_attributes}, valid_session
        expect(assigns(:group)).to eq(group)
      end

      it "re-renders the 'edit' template" do
        group = Group.create! valid_attributes
        put :update, {:id => group.to_param, :group => invalid_attributes}, valid_session
        expect(response).to render_template("edit")
      end
    end
  end

  describe "DELETE destroy" do
    it "destroys the requested group" do
      group = Group.create! valid_attributes
      expect {
        delete :destroy, {:id => group.to_param}, valid_session
      }.to change(Group, :count).by(-1)
    end

    it "redirects to the groups list" do
      group = Group.create! valid_attributes
      delete :destroy, {:id => group.to_param}, valid_session
      expect(response).to redirect_to(groups_url)
    end
  end

end

Now if you run all specs on the command line ($ rspec), they should all pass. We don’t have anything interesting to look at yet but our Rails API is now good to go.

Adding the client side

On the client side we’ll be using Yeoman, a front-end scaffolding tool. First, install Yeoman itself as well as generator-gulp-angular. (If you don’t already have npm installed, you’ll need to do that. If you’re using Mac OS with Homebrew, run brew install npm.)

$ npm install -g yo
$ npm install -g generator-gulp-angular

We’ll keep our client-side code in a directory called client. (This is an arbitrary naming choice and you could call it anything.)

$ mkdir client && cd $_

Now we’ll generate the Angular app itself. When I ran it, I made the following selections:

  • Angular version: 1.5.x
  • Modules: all
  • jQuery: 2.x
  • REST resource library: ngResource
  • Router: UI Router
  • UI framework: Bootstrap
  • Bootstrap component implementation: Angular UI
  • CSS preprocessor: Sass (Node)
  • JS preprocessor: ES6
  • HTML template engine: Jade
$ yo gulp-angular fake_lunch_hub

Start Gulp to see if it works:

$ gulp serve

Gulp should now open a new browser tab for you at http://localhost:3001/#/ where you see the “‘Allo, ‘Allo” thing. Our Angular app is now in place. It still doesn’t know how to talk to Rails, so we still have to make that part work.

Setting up a proxy

Thanks to Gerardo Gomez for helping me figure this one out.

'use strict';

var path = require('path');
var gulp = require('gulp');
var conf = require('./conf');

var browserSync = require('browser-sync');
var browserSyncSpa = require('browser-sync-spa');

var util = require('util');

var exec = require('child_process').exec;

var proxyMiddleware = require('http-proxy-middleware');

function browserSyncInit(baseDir, browser) {
  browser = browser === undefined ? 'default' : browser;

  var routes = null;
  if(baseDir === conf.paths.src || (util.isArray(baseDir) && baseDir.indexOf(conf.paths.src) !== -1)) {
    routes = {
      '/bower_components': 'bower_components'
    };
  }

  var server = {
    baseDir: baseDir,
    routes: routes,
    middleware: [
      proxyMiddleware('/api', { target: 'http://localhost:3000' })
    ]
  };

  /*
   * You can add a proxy to your backend by uncommenting the line below.
   * You just have to configure a context which will we redirected and the target url.
   * Example: $http.get('/users') requests will be automatically proxified.
   *
   * For more details and option, https://github.com/chimurai/http-proxy-middleware/blob/v0.9.0/README.md
   */
  // server.middleware = proxyMiddleware('/users', {target: 'http://jsonplaceholder.typicode.com', changeOrigin: true});

  browserSync.instance = browserSync.init({
    startPath: '/',
    server: server,
    browser: browser
  });
}

browserSync.use(browserSyncSpa({
  selector: '[ng-app]'// Only needed for angular apps
}));

gulp.task('serve', ['watch'], function () {
  browserSyncInit([path.join(conf.paths.tmp, '/serve'), conf.paths.src]);
});

gulp.task('rails', function() {
  exec('rails server');
});

gulp.task('serve:full-stack', ['rails', 'serve']);

gulp.task('serve:dist', ['build'], function () {
  browserSyncInit(conf.paths.dist);
});

gulp.task('serve:e2e', ['inject'], function () {
  browserSyncInit([conf.paths.tmp + '/serve', conf.paths.src], []);
});

gulp.task('serve:e2e-dist', ['build'], function () {
  browserSyncInit(conf.paths.dist, []);
});

Here are the things I changed, it no particular order:

  1. Added middleware that says “send requests to `/api` to `http://localhost:3000`”
  2. Added a `rails` task that simply invokes the `rails server` command
  3. Added a `serve:full-stack` task that runs the regular old `serve` task, but first runs the `rails` task

You’ll have to install `http-proxy-middleware` before continuing:

$ npm install --save-dev http-proxy-middleware

Now we can run our cool new task. Make sure neither Rails nor Gulp is already running somewhere.

$ gulp serve:full-stack

Two things should now happen:

  1. If you navigate to `http://localhost:3001/api/foo`, you should get a Rails page that says `No route matches [GET] “/api/foo”`, which means
  2. Rails is running on port 3000.

Getting Rails data to show up in our client app

Now we’ll want to get some actual data to show up in the actual HTML of our Angular app. This is a pretty easy step now that we have the plumbing taken care of. First, create some seed data:

# This file should contain all the record creation needed to seed the database with its default values.
# The data can then be loaded with the rake db:seed (or created alongside the db with db:setup).
#
# Examples:
#
#   cities = City.create([{ name: 'Chicago' }, { name: 'Copenhagen' }])
#   Mayor.create(name: 'Emanuel', city: cities.first)

Group.create([
  { name: 'Ben Franklin Labs' },
  { name: 'Snip Salon Software' },
  { name: 'GloboChem' },
  { name: 'TechCorp' },
])

Get the data into the database:

$ rake db:seed

Now let’s modify `src/app/index.route.js` to include a state for groups:

export function routerConfig ($stateProvider, $urlRouterProvider) {
  'ngInject';
  $stateProvider
    .state('home', {
      url: '/',
      templateUrl: 'app/main/main.html',
      controller: 'MainController',
      controllerAs: 'main'
    }).state('groups', {
      url: '/groups',
      templateUrl: 'app/components/groups.html',
      controller: 'GroupsController',
      controllerAs: 'groups'
    });

  $urlRouterProvider.otherwise('/');
}

Then we add `GroupsController`, which at this point is almost nothing:

export class GroupsController {
  constructor () {
  }
}

Lastly, let’s create a view at `src/app/components/groups.jade`:

div(ng-include='', src="'app/components/navbar/navbar.html'")

.container
  h1 Groups

If you now navigate to `http://localhost:3001/#/groups`, you should see a big `h1` that says “Groups”. So far we’re not talking to Rails at all yet. That’s the very next step.

A good library for Angular/Rails resources is called, straightforwardly, angularjs-rails-resource. It can be installed thusly:

$ bower install --save angularjs-rails-resource

Now let’s add two things to `src/app/index.module.js`: the `rails` module and a resource called `Group`.

/* global malarkey:false, moment:false */

import { config } from './index.config';
import { routerConfig } from './index.route';
import { runBlock } from './index.run';
import { MainController } from './main/main.controller';
import { GroupsController } from './components/groups.controller';
import { GithubContributorService } from '../app/components/githubContributor/githubContributor.service';
import { WebDevTecService } from '../app/components/webDevTec/webDevTec.service';
import { NavbarDirective } from '../app/components/navbar/navbar.directive';
import { MalarkeyDirective } from '../app/components/malarkey/malarkey.directive';

angular.module('fakeLunchHub', [
  'ngAnimate',
  'ngCookies',
  'ngTouch',
  'ngSanitize',
  'ngMessages',
  'ngAria',
  'ngResource',
  'ui.router',
  'ui.bootstrap',
  'toastr',
  'rails'
]).constant('malarkey', malarkey)
  .constant('moment', moment)
  .config(config)
  .config(routerConfig)
  .run(runBlock)
  .service('githubContributor', GithubContributorService)
  .service('webDevTec', WebDevTecService)
  .controller('MainController', MainController)
  .controller('GroupsController', GroupsController)
  .directive('acmeNavbar', NavbarDirective)
  .directive('acmeMalarkey', MalarkeyDirective)
  .factory('Group', railsResourceFactory => {
    return railsResourceFactory({
      url: '/api/groups',
      name: 'group'
    });
});

Now let’s add a line to our controller to make the HTTP request:

export class GroupsController {
  constructor ($scope, Group) {
    'ngInject';

    Group.query().then(groups => $scope.groups = groups);
  }
}

And some code in our template to show the group names:

div(ng-include="'app/components/navbar/navbar.html'")

.container
  h1 Groups
  ul
    li(ng-repeat='group in groups') {{ group.name }}

If you now visit `http://localhost:3001/#/groups`, you should see your group names there. Congratulations! You just wrote a single-page application. It’s a trivial and useless single-page application, but you’re off to a good start. In my experience the plumbing is the hardest part.

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