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mustache and handlebars template handling in Rails 3.x and Rails 4.x
Ruby JavaScript HTML Other


A Rails 3.x and Rails 4.x compatible Mustache/Handlebars template handler, with support for partials and a couple extra niceties to make sharing the raw templates with client-side javascript a little easier. It's a one-stop shop for your facial-hair-inspired templates.

Build Status

Mustache template caching is in 1.1+

I'm investigating whether or not this is something that can be/needs to be ported to handlebars.

Rails 4 Support is in 1.0.3+

If you want Rails 4, you'll have to use 1.0.3.


gem "mustache" # or "handlebars"
gem "stache"

Install the gem. If you want to override any of the configuration options (see stache/config), toss an initializer in config/initializers and:

Stache.configure do |c|
  # This is probably the one you'll want to change
  # it defaults to app/templates
  c.template_base_path = "..."

  # This lets you indicate the name of a module that
  # namespaces all your view classes, useful, if you
  # have a naming conflict, such as with a mailer
  c.wrapper_module_name = "..."

  c.use :mustache
  # and / or
  c.use :handlebars

  # Set it to true if template path should be included in
  # script's id tag as a underscored prefix. It can be
  # overwritten by an id param in `#template_include_tag`.
  c.include_path_in_id = false

  # Caching (new in 1.1.0, Mustache-only for now)
  # Any ActiveSupport::Cache should work fine.
  # If you enable this in development, you will lose automagical template reloading!
  c.template_cache = if Rails.env.production?

# or if the block style ain't yer thang, just:
Stache.template_base_path = File.join(Rails.root, "app", "şablon")
Stache.template_cache = if Rails.env.production?

Helper methods

There is currently just one helper method; template_include_tag. If you pass it the name of a partial it will write out the contents of the partial in a script tag, so that you can access it from within your JavaScript.

<%= template_include_tag 'profiles/profile' %>

Specify the template to include with a path relative to your template base path (i.e. profiles/profile rather than just profile).

A View Class of your Very Own

To facilitate easy integration, 'Stache comes packaged with a fully-functioning subclass of Mustache, called Stache::Mustache::View. It will try to find a more appropriate view class to provide to the template renderer based on the template name, but if one cannot be found it will automatically give ya a Stache::Mustache::View so you can have something.

Needless to say, it's probably better if your custom View objects are subclasses of Stache::Mustache::View. That way we can all be sure that the handler will render correctly.

An example by way of explanation:

With a template app/templates/profiles/index, Stache will look for a view named Profiles::Index, and, if not found, will just use the base Stache::Mustache::View. Stache adds app/views to Rails' autoload paths, so here's a sample directory structure and some sample files:

# in profiles/index.rb
module Profiles
  class Index < ::Stache::Mustache::View
    def my_view_helper_method
<!-- in the view, then -->
<p>Here's a helper_method call: {{ my_view_helper_method }}</p>

With the wrapper_module_name configuration set to "Wrapper":

With a template app/templates/profiles/index, Stache will look for a view named Wrapper::Profiles::Index, and, if not found, will just use the base Stache::Mustache::View.


Handlebars will have full access to your rails view helpers.

I'm a handlebars template. Look at me call a helper: {{{image_path my_image}}}

You can subclass Stache::Handlebars::View in the same way as mustache above, but there isn't as much point in doing so.

View Specs

Yes, you can write view specs using RSpec for your Stache templates! You can use RSpec's assign method to assign values to view instance variables, which will then be be available to the Stache view, either as instance variables, or via an accessor. Any instance variables defined in the RSpec example will also be similarly available, so

    it "should display my instance variable" do
      assign(:resource, "Foo")


    it "should display my instance variable" do
      @resource = "Foo"

both make @resource available to the Stache view.

Non-Mustache Partials

Yes, you can include non-Mustache partials (and templates) in your Stache templates. However, the {{>partial_name_here}} syntax in the template won't find a non-Mustache template. You can define a method in the view and reference it in the template. The view method should use @view.render to render the non-Mustache partial and return its content. Example:

Mustache template:



   class MyPage < ::Stache::Mustache::View
     def my_haml_sidebar
       @view.render partial: 'somewhere/some_haml_partial_name'

Stache + ActionMailer

Stache should work just fine with ActionMailer, with one minor configuration:

Assuming you have a view directory like this:


You'd define your UserMailer like so:

class UserMailer < ActionMailer::Base
  default from: ''

  def confirm_sign_up
    mail(to: '', subject: 'Welcome to StacheMail') do |format|

N.B. the do |format| block is very important: ActionMailer will render the code in the .rb file as a multipart text/html component, which is probably not what you want unless you really want to show off your View class to all your recipients :).

The confirm_sign_up.rb file contains an utterly normal ::Stache::Mustache::View subclass, e.g. Note that it is nested inside the UserMailer class.

class UserMailer
  class ConfirmSignUp < ::Stache::Mustache::View
    def full_name
      ["Bob", "Jones"].join(' ')

Of Note

This is code that was ripped out of a research project. It probably has some rough edges.

Thanks to

This project builds on work done by the following people and projects:

So: thanks a ton to those guys.


  • afeld provided 1.8.7 compatibility fixes.
  • subwindow provided some much needed love for Stache::Mustache::View exception handling.
  • solotimes provided better support for non-standard encodings.
  • ajacksified cleaned up template extension handling.
  • ayamomiji extended the #template_include_tag to pass through the full range of #content_tag options.
  • awestendorf requested that View#partial not be so particular about leading underscores. Though I didn't use his code, his prompt lead me to investigate how to properly use Rails' internal template lookup code.
  • zombor contributed an overhaul to the Mustache renderer that puts Mustache classes themselves in control of the render chain, not Rails.
  • kategengler contributed a patch to allow folks to specify a namespace for their view objects.
  • joker1007 contributed a patch making the autoload paths setup more broadly compatible.
  • kianw contributed a patch making RSpec a little easier to use.
  • MarkusHarmsen added Mustache caching, leading to HUGE performance increases. Thanks!

Thanks a ton to all of the contributors, equally. This would never have grown beyond a mediocre tool that rendered partials without their help!

Note on Patches/Pull Requests

  • Fork the project.
  • Make your feature addition or bug fix.
  • Add tests for it. This is important so I don't break it in a future version unintentionally.
  • 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)
  • Send me a pull request. Bonus points for topic branches.


Copyright (c) 2011-2014 Matt Wilson / Agora Games. See LICENSE for details.

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