ember-rails

ember-rails

ember-rails makes developing an Ember.JS application much easier in Rails 4.2+.

The following functionalities are included in this gem:

• Pre-compiling of your handlebars templates when building your asset pipeline.
• Inclusion of development and production copies of Ember, Ember Data and Handlebars.
• Inclusion of ActiveModel::Serializer for integration with Ember Data.

You can see an example of how to use the gem here. There is also a great tutorial by Dan Gebhardt called "Beginning Ember.js on Rails" which is a great read if you're just starting out with Rails and Ember.js.

Getting started

• Add the gem to your application Gemfile:

gem 'ember-rails'
# gem 'ember-source' # You can specify the Ember.js version you want to use.(such as '~> 1.13.0')

• Run bundle install
• Next, generate the application structure:

$ rails generate ember:bootstrap

• Restart your server (if it's running)

Building a new project from scratch

Rails supports the ability to build projects from a template source ruby file.

To build an Ember centric Rails project you can simply type the following into your command line:

$ rails new my-app -m https://emberjs.com/edge_template.rb

Read more about Rails application templates and take a look at the edge_template.rb source code.

Notes:

To install the latest builds of ember and ember-data. It should be noted that the examples in the getting started guide have been designed to use the released version of ember:

$ rails generate ember:install

You'll probably need to clear out your cache after doing this with:

$ rake tmp:clear

Also, ember-rails includes some flags for the bootstrap generator:

--ember-path or -d   # custom ember path
--skip-git or -g     # skip git keeps
--javascript-engine  # engine for javascript (js, coffee, em or es6)
--app-name or -n     # custom ember app name

For CoffeeScript support

Add coffee-rails to the Gemfile

gem 'coffee-rails'

Run the bootstrap generator in step 4 with an extra flag instead:

$ rails g ember:bootstrap -g --javascript-engine coffee

For EmberScript support

EmberScript is a dialect of CoffeeScript with extra support for computed properties (which do not have to be explicitly declared), the class / extends syntax, and extra syntax to support observers and mixins.

To get EmberScript support, make sure you have the following in your Gemfile:

gem 'ember_script-rails', :github => 'ghempton/ember-script-rails'

You can now use the flag --javascript-engine=em to specify EmberScript assets in your generators, but all of the generators will default to using an EmberScript variant first.

For ES6 support

Ember.js recommends using ES6 syntax. It is supported by Babel via ember-es6_template.

Run the bootstrap generator with an extra flag:

$ rails g ember:bootstrap --javascript-engine=es6

Note:

To use ES6 module in your application, the following configuration is required:

Single Ember Application

This is the case for single Ember application in app/assets/javascripts (not under the subdirectory).

my-app.es6

import Application from 'ember-rails/application';

const App = Application.extend({
  // Configure your application.
});

App.create();

import Application from 'ember-rails/application'; and Application.extend() is important. It provides customized Ember application to resolve dependencies from ES6 modules instead of Ember.Application.extend().

application.js

//= require jquery
//= require ember
//= require ember-data
//= require ember-rails/application
//= require ./my-app
//= require_self

require('my-app'); // Run your Ember.js application

Multiple Ember Application

This is the case for multiple Ember application in your Rails application. (Or your Ember application is placed in sub directories of app/assets/javascripts.)

First, you should configure config.ember.module_prefix to nil. To disable prepending the module prefix to you modules.

config/application.rb

config.ember.module_prefix = nil

Second, please specify modulePrefix to your Ember application.

my-app/application.module.es6

import Application from 'ember-rails/application';
import loadInitializers from 'ember/load-initializers';

const App = Application.extend({
  modulePrefix: 'my-app' // This value should be the same as directory name.
});

loadInitializers(App, 'my-app');

App.create();

Last, add your endpoint to where you want to run your Ember application.

require('my-app'); // Run your Ember.js application

Configuration Options

The following options are available for configuration in your application or environment-level config files (config/application.rb, config/environments/development.rb, etc.):

Configuration Option	Description
config.ember.variant	Determines which Ember variant to use. Valid options: :development, :production. Defaults to :production in production, and :development everywhere else.
config.ember.app_name	Specificies a default application name for all generators.
config.ember.ember_path	Specifies a default custom root path for all generators.
config.ember.module_prefix	Sets module prefix for es6 module. This option is used for only es6 scripts. Default value: ember-app.
config.ember.prefix_files	Sets some file names to add config.ember.module_prefix into its file name as es6 module name.
config.ember.prefix_dirs	Sets some dir names to add config.ember.module_prefix into its directory name as es6 module name.
config.handlebars.precompile	Enables or disables precompilation. Default value: true.
config.handlebars.templates_root	Sets the root path (under app/assets/javascripts) for templates to be looked up in. Default value: "templates".
config.handlebars.templates_path_separator	The path separator to use for templates. Default value: '/'.
config.handlebars.output_type	Configures the style of output (options are :amd and :global). Default value: :global.
config.handlebars.amd_namespace	Configures the module prefix for AMD formatted output. Default value: nil.
config.handlebars.ember_template	Default which Ember template type to compile. Valid options: 'Handlebars', HTMLBars. Defaults to 'Handlebars' when Ember::VERSION is under 1.10.0, HTMLBars when Ember::VERSION is over 1.10.0.

Note:

In a mountable engine, ember-rails will not recognize any configurations. Instead, use command line options.

Enabling Features with Feature Flags

See the guide and check features.json for the version of Ember you're using.

If a feature is set to false, you will need to compile ember from source yourself to include it.

Important note for projects that render JSON responses

ember-rails includes active_model_serializers which affects how ActiveModel and ActiveRecord objects get serialized to JSON, such as when using render json: or respond_with. By default active_model_serializers adds root elements to these responses (such as adding {"posts": [...]} for render json: @posts) which will affect the structure of your JSON responses.

To disable this effect on your JSON responses, put this in an initializer:

# Stop active_model_serializers from adding root elements to JSON responses.
ActiveModel::Serializer.root = false
ActiveModel::ArraySerializer.root = false

See the active_model_serializers documentation for a more complete understanding of other effects this dependency might have on your app.

Architecture

Ember does not require an organized file structure. However, ember-rails allows you to use rails g ember:bootstrap to create the following directory structure under app/assets/javascripts:

├── adapters
├── components
├── controllers
├── helpers
├── mixins
├── models
├── practicality.coffee
├── router.coffee
├── routes
├── templates
│   └── components
└── views

Additionally, it will add the following lines to app/assets/javascripts/application.js. By default, it uses the Rails Application's name and creates an rails_app_name.js file to set up application namespace and initial requires:

//= require ember
//= require ember-data
//= require_self
//= require rails_app_name
RailsAppName = Ember.Application.create();

Example:

…

If you want to avoid .gitkeep files, use the skip git option like this: rails g ember:bootstrap -g.

Ask Rails to serve HandlebarsJS and pre-compile templates to Ember by putting each template in a dedicated ".hbs", ".js.hjs" or ".handlebars" file (e.g. app/assets/javascripts/templates/admin_panel.hbs) and including the assets in your layout:

If you want to avoid the templates prefix, set the templates_root option in your application configuration block:

config.handlebars.templates_root = 'ember_templates'

If you store templates in a file like app/assets/javascripts/ember_templates/admin_panel.hbs after setting the above config, it will be made available to Ember as the admin_panel template.

(Note: you must clear the local sprockets cache after modifying templates_root, stored by default in tmp/cache/assets)

Default behavior for ember-rails is to precompile handlebars templates. If you don't want this behavior you can turn it off in your application configuration (or per environment in: config/environments/development.rb) block:

config.handlebars.precompile = false

(Note: you must clear the local sprockets cache if you disable precompilation, stored by default in tmp/cache/assets)

Bundle all templates together thanks to Sprockets, e.g create app/assets/javascripts/templates/all.js with:

//= require_tree .

Now a single line in the layout loads everything:

Note about ember components

When necessary, ember-rails adheres to a conventional folder structure. To create an ember component you must define the handlebars file inside