Question

I have a sinatra app that is mostly using erb for templates, but I am adding some mustache partials for blocks of html that need to be rendered on both the server and client side. I have a “views” directory where I’m keeping all my templates, including the mustache templates I’m adding. For example, the structure looks something like this:

views/
    index.html.erb
    _wingding.html.erb
    _widget.html.mustache

Let’s say I’m rendering index.html.erb using this endpoint:

get '/' do
    erb :index
end

And inside that template, I want to render both of the above partials [UPDATE: it turns out this partial method is not built into sinatra, but is included via a gem (see my answer for details), but it still relies on the main sinatra rendering component, so the problem here still stands.]. So index.html.erb contains:

<%= partial :wingding %>
<%= partial :widget %>

The erb partial (wingding) renders fine, but the mustache partial (widget) does not. It causes the application to throw an exception:

Template engine not found: mustache

I have included the ‘mustache’ gem in the project. I tried 'require mustache/sinatra' and register Mustache::Sinatra. Both of these statements worked, but didn’t solve the problem above. Any idea how to tell sinatra about mustache so that it can render mustache partials?

I’m setting my views directory by including this configuration:

configure do
    set :views, File.join(File.dirname(__FILE__), 'views')
end

Version numbers:

• sinatra 1.3.1
• mustache 0.99.4
• ruby 1.9.3

Answer 1

So it turns out the gem listed in the solution in my other answer caches output, meaning you can’t use it to include the same partial with different locals in the same request, which makes it worthless for my purposes. So here’s another (admittedly hackish) solution that I’ve settled on. I created a helper that will just deliver the contents of a given view:

helpers do
    def template_contents(path)
        File.open("#{settings.views}/#{path}") { |f| f.read }
    end
end

Then, I just do a regular Mustache#render:

<%= Mustache.render(template_contents('_widget.html.mustache'), { ... }) %>

This works great for my use case.