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

For Rails 3, the with_format block works, but it's a little different:

  def with_format(format, &block)
    old_formats = formats
    self.formats = [format]
    block.call
    self.formats = old_formats
    nil
  end

Answer 2

I had a file named 'api/item.rabl' and I wanted to render it from an HTML view so I had to use:

render file: 'api/item', formats: [:json]

(file because the file have no underscore in the name, formats and not format (and passes and array))

Answer 3

Just elaborating on what zgchurch wrote:

• taking exceptions into account
• returning the result of the called block

Thought it might be useful.

def with_format(format, &block)
  old_formats = formats
  begin
    self.formats = [format]
    return block.call
  ensure
    self.formats = old_formats
  end
end

Answer 4

What's wrong with

render :partial => '/foo/baz.html.erb'

? I just tried this to render an HTML ERB partial from inside an Atom builder template and it worked fine. No messing around with global variables required (yeah, I know they have "@" in front of them, but that's what they are).

Your with_format &block approach is cool though, and has the advantage that you only specify the format, whereas the simple approach specifies the template engine (ERB/builder/etc) as well.

Answer 5

Building on roninek's response, I've found the best solution to be the following:

in /app/helpers/application.rb:

def with_format(format, &block)
  old_format = @template_format
  @template_format = format
  result = block.call
  @template_format = old_format
  return result
end

In /app/views/foo/bar.json:

<% with_format('html') do %>
  <%= h render(:partial => '/foo/baz') %>
<% end %>

An alternate solution would be to redefine render to accept a :format parameter.

I couldn't get render :file to work with locals and without some path wonkiness.

Answer 6

Beginning with Rails 3.2.3, when calling render :partial (only works outside of the respond_to block).

render formats: [ :html ]

instead of

render format: 'html'