“render :nothing => true” returns empty plaintext file?

Since Rails 4, head is now preferred over render :nothing.¹

head :ok, content_type: "text/html"

# or (equivalent)

head 200, content_type: "text/html"

is preferred over

render nothing: true, status: :ok, content_type: "text/html"

# or (equivalent)

render nothing: true, status: 200, content_type: "text/html"

They are technically the same. If you look at the response for either using cURL, you will see:

HTTP/1.1 200 OK
Connection: close
Date: Wed, 1 Oct 2014 05:25:00 GMT
Transfer-Encoding: chunked
Content-Type: text/html; charset=utf-8
X-Runtime: 0.014297
Set-Cookie: _blog_session=...snip...; path=/; HttpOnly
Cache-Control: no-cache

However, calling head provides a more obvious alternative to calling render :nothing because it’s now explicit that you’re only generating HTTP headers.

1. http://guides.rubyonrails.org/layouts_and_rendering.html#using-head-to-build-header-only-responses