Odtnhj

Downloading off the public folder takes 2 seconds.

Downloading the same file using the send_file method below takes nearly a minute.

 def download
 file = FileUpload.find params[:id]
 file_path = Rails.root.join('private', file.name)
 send_file(file_path,
 x_sendfile: true, 
 disposition: 'attachment')
 end

I have tried changing buffer size and so on but it's still extremely slow, slower than the database & send_data combination.

Apart from ditching Rails entirely, is there an simple solution to this?

After some search I realized my question was a little silly:

Puma is, in practice, an Application server

To be precise, Puma calls itself a web server but rails usage wise it seems either Apache or Nginx is inserted between the user and Puma in most cases.

Puma itself, as of now, does not seem to support either X-Sendfile nor X-Accel-Redirect. It's up to Apache or Nginx.

Getting it work with rails5, puma, nginx in development environment

Steps are for ubuntu 16lts, puma version 3.9.1, nginx/1.10.0 (Ubuntu), Rails 5.1.1, ruby 2.4.0p0

sudo apt install nginx
sudo ufw allow 'Nginx HTTP'
sudo trash /etc/nginx/sites-enabled/defualt #renaming did not work
sudo touch /etc/nginx/sites-available/rails.conf
sudo ln -sf /etc/nginx/sites-available/rails.conf /etc/nginx/stes-enabled/rails.conf

Edited: /etc/nginx/sites-available/rails.conf

upstream uploader 
 server localhost:3000 fail_timeout=0;


server 
 listen 80;
 listen [::]:80;
 #Your public folder path
 root /home/d/WebApp/uploader/public;
 location ~ ^/assets/ 
 expires max;
 gzip_static on;
 gzip_vary on;
 add_header Cache-Control public;
 break;
 
 location / 
 proxy_pass http://uploader;# http://appNameYouChooseAbove
 proxy_set_header Host $host;
 proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

 #Inform rails how to ask nginx to deliver files.
 #nginx does not take an absolute file path, 
 #it needs url.
 #X-Accel-Mapping contains info needed to convert 
 #an absolute file path to an url.
 proxy_set_header X-Accel-Mapping /home/d/WebApp/uploader/private=/available_only_when_redirected_here_by_upstream_server; 
 #The above is used by rails to translate:
 #e.g.
 # /home/d/WebApp/uploader/private/file.zip 
 # to
 # available_only_when_redirected_here_by_upstream_server/file.zip
 # When rails access the above, nginx delivers the file to the client 
 proxy_set_header X-Sendfile-Type X-Accel-Redirect; 
 

 location /available_only_when_redirected_here_by_upstream_server 
 #without alias, nginx tries to open file at:
 #"root + this location + filename"
 #e.g.
 # given file file.zip
 # root of "/home/d/WebApp/uploader/public" as defined above.
 # this lociation which is "available_only_when_redirected_here_by_upstream_server"
 #
 # /home/d/WebApp/uploader/public/ava...server/file.zip
 #
 alias /home/d/WebApp/uploader/private/;
 # internal ensures this url in only available from upsteam location/application server
 internal;
 

 error_page 500 502 503 504 /500.html;
 error_page 404 /404.html;
 error_page 422 /422.html;
 client_max_body_size 4G;
 keepalive_timeout 10;

Append the below to config/environment/development.rb

config.action_dispatch.x_sendfile_header = 'X-Accel-Redirect' # for NGINX

Restart servers

bundle exec rails s Puma
sudo service nginx restart

P.S

Direct access to localhost:3000 bypasses nginx; omit port number to go through nginx.

P.P.S

Edited Nginx config as it was not working;I don't know why download speed improved when it should not!

"X-Accel-Mapping header missing" means X-Accel-Redirect not working.

X-Accel-Mapping can be defined in inner context like:

location / 
 location /static 
 proxy_pass http://uploader;# http://appNameYouChooseAbove
 proxy_set_header Host $host;
 proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
 proxy_set_header X-Accel-Mapping /...=/...;
 

and redirection targets can be created as many as needed, so it's not as bad as it appears.

Be warned, however, Nginx configuration is a wild ride. Without proxy_set_header etc, introducing inner context morphs url to root path + location form and gosh it was not very intuitive!

When using Heroku or similar services, sometimes it isn't possible (or convenient) to configure nginx.

In these cases it makes sense to use an application server that supports X-Sendfile, such as iodine or agoo.

My biased suggestion is to use the iodine server with it's static file service option in the procfile, for example:

iodine -w 4 -t 16 -www ./public

Since assets are compiled to ./public/assets*, than the static file requests will be directly handled by iodine without ever entering the Ruby application (the C server layer will handle them).

* RAILS_ENV=production bin/rails assets:precompile compiles assets to ./public/assets