How do I render a partial of a different format in Rails?

Question

I\'m trying to generate a JSON response that includes some HTML. Thus, I have /app/views/foo/bar.json.erb:

{
  someKey: \'some value\',
  someH         


        

Answer 1

In Rails 3, the View has a formats array, which means you can set it to look for [:mobile, :html]. Setting that will default to looking for :mobile templates, but fall back to :html templates. The effects of setting this will cascade down into inner partials.

The best, but still flawed way, that I could find to set this was to put this line at the top of each full mobile template (but not partials).

<% self.formats = [:mobile, :html] %>

The flaw is that you have to add that line to multiple templates. If anyone knows a way to set this once, from application_controller.rb, I'd love to know it. Unfortunately, it doesn't work to add that line to your mobile layout, because the templates are rendered before the layout.

Answer 2

You have two options:

1) use render :file

render :file => "foo/_baz.json.erb"

2) change template format to html by setting @template_format variable

<% @template_format = "html" %>
<%= h render(:partial => '/foo/baz') %>

Answer 3

It seems that passing a formats option will render it properly in newer Rails version, at least 3.2:

{
  someKey: 'some value',
  someHTML: "<%= h render('baz', formats: :html) -%>"
}

Answer 4

I came across this thread when I was trying to render an XML partial in another xml.builder view file. Following is a nice way to do it

xml.items :type => "array" do
    @items.each do |item|
        xml << render(:partial => 'shared/partial.xml.builder', :locals => { :item => item })
    end
end

And yeah... Full file name works here as well...

Answer 5

Rails 4 will allow you to pass a formats parameter. So you can do

render(:partial => 'form', :formats => [:html])} 

Note you can do something similar in Rails 3 but it wouldn't pass that format to any sub partials (if form calls other partials).

You can have the Rails 4 ability in Rails 3 by creating config/initializers/renderer.rb:

class ActionView::PartialRenderer
  private
  def setup_with_formats(context, options, block)
    formats = Array(options[:formats])
    @lookup_context.formats = formats | @lookup_context.formats
    setup_without_formats(context, options, block)
  end

  alias_method_chain :setup, :formats
end

See http://railsguides.net/2012/08/29/rails3-does-not-render-partial-for-specific-format/