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ember-rails makes developing an Ember.JS application much easier in Rails 3.1+.

The following functionalities are included in this gem:

  • Pre-compiling of your handlebars templates when building your asset pipeline.
  • Includes development and production copies of Ember, Ember Data and Handlebars.
  • Includes 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', '1.5.0' # or the version you need
  • 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

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


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

For CoffeeScript support

  1. Add coffee-rails to the Gemfile
gem 'coffee-rails'
  1. Run the bootstrap generator in step 4 with an extra flag instead:
rails g ember:bootstrap -g --javascript-engine coffee


Ember-rails include some flags options for bootstrap generator:

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

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.

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.):

  • config.ember.variant - Used to determine which Ember variant to use. Valid options: :development, :production.
  • config.ember.app_name - Used to specify a default application name for all generators.
  • config.ember.ember_path - Used to specify a default custom root path for all generators.
  • config.handlebars.precompile - Used to enable or disable precompilation. Default value: true.
  • config.handlebars.templates_root - Set 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.


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:


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


rails g ember:bootstrap
  insert  app/assets/javascripts/application.js
  create  app/assets/javascripts/models
  create  app/assets/javascripts/models/.gitkeep
  create  app/assets/javascripts/controllers
  create  app/assets/javascripts/controllers/.gitkeep
  create  app/assets/javascripts/views
  create  app/assets/javascripts/views/.gitkeep
  create  app/assets/javascripts/helpers
  create  app/assets/javascripts/helpers/.gitkeep
  create  app/assets/javascripts/components
  create  app/assets/javascripts/components/.gitkeep
  create  app/assets/javascripts/templates
  create  app/assets/javascripts/templates/.gitkeep
  create  app/assets/javascripts/templates/components
  create  app/assets/javascripts/templates/components/.gitkeep
  create  app/assets/javascripts/app.js

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 ".js.hjs", ".hbs" or ".handlebars" file (e.g. app/assets/javascripts/templates/admin_panel.handlebars) and including the assets in your layout:

<%= javascript_include_tag "templates/admin_panel" %>

If you want to strip template root from template names, add templates_root option to your application configuration block. By default, templates_root is 'templates'.

config.handlebars.templates_root = 'ember_templates'

If you store templates in a file like app/assets/javascripts/ember_templates/admin_panel.handlebars 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:

<%= javascript_include_tag "templates/all" %>

If you use Slim or Haml templates, you can use handlebars filter :

    <button {{action anActionName}}>OK</button>

It will be translated as :

<script type="text/x-handlebars">
    <button {{action anActionName}}>OK</button>

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 the components folder under the templates folder of your project to properly register your handlebars component file.


With the following folder structure:


and a my-component.handlebars file with the following contents

<h1>My Component</h1>

will produce the following handlebars output

<script type="text/x-handlebars" id="components/my-component">
  <h1>My Component</h1>

You can reference your component inside your other handlebars template files by the handlebars file name:

 {{ my-component }}

A note about upgrading ember-rails and components

The ember-rails project now includes generators for components. If you have an existing project and need to compile component files you will need to include the components folder as part of the asset pipeline. A typical project expects two folders for components related code:

  • assets/javascripts/components/ to hold the component javascript source
  • assets/javascripts/templates/components/ to hold the handlebars templates for your components

Your asset pipeline require statements should include reference to both e.g.


//= require_tree ./templates
//= require_tree ./components


#= require_tree ./templates
#= require_tree ./components

These are automatically generated for you in new projects you when you run the ember:bootstrap generator.

Specifying Different Versions of Ember/Handlebars/Ember-Data

By default, ember-rails ships with the latest version of Ember, Handlebars, and Ember-Data.

To specify a different version that'll be used for both template precompilation and serving to the browser, you can specify the desired version of one of the above-linked gems in the Gemfile, e.g.:

gem 'ember-source', '1.0.0'

You can also specify versions of 'handlebars-source' and 'ember-data-source', but note that an appropriate 'handlebars-source' will be automatically chosen depending on the version of 'ember-source' that's specified.

You can also override the specific ember.js, handlebars.js, and ember-data.js files that'll be required by the Asset pipeline by placing these files in vendor/assets/ember/development and vendor/assets/ember/production, depending on the config.ember.variant you've specified in your app's configuration, e.g.:

config.ember.variant = :production
#config.ember.variant = :development

Updating Ember

If at any point you need to update Ember.js from any of the release channels, you can do that with

rails generate ember:install --channel=<channel>

This will fetch both Ember.js and Ember Data from and copy to the right directory. You can choose between the following channels:

  • canary - This references the 'master' branch and is not recommended for production use.
  • beta - This references the 'beta' branch, and will ultimately become the next stable version. It is not recommended for production use.
  • release - This references the 'stable' branch, and is recommended for production use.

When you don't specify a channel, the release channel is used.

It is also possible to download a specific tagged release. To do this, use the following syntax:

rails generate ember:install --tag=v1.2.0-beta.2 --ember

or for ember-data

rails generate ember:install --tag=v1.0.0-beta.2 --ember-data

Note on Patches/Pull Requests

  1. Fork the project.
  2. Make your feature addition or bug fix.
  3. Add tests for it. This is important so I don't break it in a future version unintentionally.
  4. Commit, do not mess with rakefile, version, or history. (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)
  5. Send me a pull request. Bonus points for topic branches.
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