"render :nothing => true" returns empty plaintext file?

I'm on Rails 2.3.3, and I need to make a link that sends a post request.

I have one that looks like this:

= link_to('Resend Email', 
  {:controller => 'account', :action => 'resend_confirm_email'}, 
  {:method => :post} )

Which makes the appropriate JavaScript behavior on the link:

<a href="/account/resend_confirm_email" 
  onclick="var f = document.createElement('form'); 
  f.style.display = 'none'; 
  this.parentNode.appendChild(f); 
  f.method = 'POST'; 
  f.action = this.href;
  var s = document.createElement('input'); 
  s.setAttribute('type', 'hidden'); 
  s.setAttribute('name', 'authenticity_token'); 
  s.setAttribute('value', 'EL9GYgLL6kdT/eIAzBritmB2OVZEXGRytPv3lcCdGhs=');
  f.appendChild(s);
  f.submit();
  return false;">Resend Email</a>'

My controller action is working, and set to render nothing:

respond_to do |format|
  format.all { render :nothing => true, :status => 200 }
end

But when I click the link, my browser downloads an empty text file named "resend_confirm_email."

What gives?

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

UPDATE: This is an old answer for legacy Rails versions. For Rails 4+, see William Denniss' post below.

Sounds to me like the content type of the response isn't correct, or isn't correctly interpreted in your browser. Double check your http headers to see what content type the response is.

If it's anything other than text/html, you can try to manually set the content type like this:

render :nothing => true, :status => 200, :content_type => 'text/html'