Rails sends 0 byte files using send_file

send_file has :x_sendfile param which defaults to true in Rails 3.This feature offloads streaming download to front server - Apache (with mod_xsendfile) or lighttpd, by returning empty response with X-Sendfile header with path.

Nginx uses X-Accel-Redirect header for same functionality but you have toconfigure Rails properly in proper environment file:

config.action_dispatch.x_sendfile_header = 'X-Accel-Redirect'

Rails 3 update: this line already exists in production.rb, just uncomment it.

Add sendfile on; to your nginx config to utilize header sent by Rails.Remember the absolute path must be used and nginx must have read access to file.

Another way for aliased files:

For better security I use aliases in nginx instead of absolute paths,however send_file method checks existence of file which fails with alias.Thus I changed my action to:

  head(        'X-Accel-Redirect'=> file_item.location,        'Content-Type' => file_item.content_type,        'Content-Disposition' => "attachment; filename=\"#{file_item.name}\"");  render :nothing => true;

In Rails 3, just uncomment the line config.action_dispatch.x_sendfile_header = 'X-Accel-Redirect' in production.rb inside environments folder.

Yes, I had the same problem with X-sendfile being enabled by default in Rails 3 too.

If you have large volume of "send_file" calls,you can just comment-out following line in config/environments/production.rb:

#config.action_dispatch.x_sendfile_header = "X-Sendfile"

Then send_file method started working perfectly.

Because I can't install x-sendfile extension to Apache, I just searched a little and found this.

I hope it helps.