Rails 3.2.x: Serving files with nginx using X-Accel-Redirect header (capistrano deploy)

serving_files_with_nginx.txt

# Assumptions:

* Rails 3.2.x
* nginx
* capistrano deploy
* "X-Accel-Mapping header missing" messages in nginx error.log file
* You want to serve static files with nginx instead of Rails

# nginx configuration:

passenger_set_cgi_param HTTP_X_ACCEL_MAPPING "/home/user/rails_app/shared/files/=/documents/";
passenger_pass_header X-Accel-Redirect;

location ~ ^/documents/(\d\d\d)/(\d\d\d)/(\d\d\d)/(.*)$ {
  alias /home/user/rails_app/shared/files/$1/$2/$3/$4;
  internal;
}

# DocumentsController:
def index
  @document = Document.find(params[:id])
  # @document.path #=> /home/user/releases/20130111141529/files/000/000/001/file.txt
  send_file @document.path.sub(/releases\/\d{14}/, 'shared')
end

# Rails: config/environments/production.rb
config.action_dispatch.x_sendfile_header = 'X-Accel-Redirect'

# Request: 
http://localhost:3000/documents/1

# References:

* http://stackoverflow.com/questions/954470/serving-large-files-through-nginx-via-rails-2-3-using-x-sendfile
* http://airbladesoftware.com/notes/rails-nginx-x-accel-mapping
* http://wiki.nginx.org/HttpCoreModule#alias
* http://greenlegos.wordpress.com/2011/09/12/sending-files-with-nginx-x-accel-redirect/
* http://stackoverflow.com/questions/6237016/message-x-accel-mapping-header-missing-in-nginx-error-log

Hi, this was really useful to solve our similar issue! We just did something different which was to use the Pathname library instead of the method sub to obtain the real path to the file, by doing:

Pathname.new(@document.path).realpath

It looked more robust! =)

Thanks though!