My application runs on a Nginx and passenger server. Inside the production.rb I see a line says:
# Specifies the header that your server uses for sending files.
config.action_dispatch.x_sendfile_header = 'X-Accel-Redirect' # for NGINX
How does it Specifies header to sending files? How does Rails sends file without having this turned on?
Is it a good practice so turn this on? Does it make my application to run faster?
The behavior is explained in the send_file documentation
You should use this option, it will make your application faster and it is good practice to do so.
If you don't use this option, the file will be read by the ruby process, sent to nginx and then to the client.
Related
I have a rails app where users can manage large files (currently up to 15 GB). They have also the possibility to download the stored files.
Everything works perfect for files < 510 MB. But for > 510 MB, the download stops after 522,256 KB (510 MB).
I think thin produces this issue. When I start my dev server using thin, I cannot download the complete file. When I start the dev server using webrick, everything works.
I used top to compare the RAM/CPU behavior, but both server, thin and webrick, behave the same way. In development, both server read the complete file into RAM and then send it to the user/client.
I tried to change some options of send_file like stream, or buffer_size. I also set length manually. But again, I was not able to download the complete file using thin.
I can reproduce this behavior using Firefox, Chrome, and curl.
The problem is that my productive rails app uses 4 thin servers behind an nginx proxy. Currently, I cannot use unicorn, or passenger.
In development, I use thin 1.6.3, rails 4.1.8, ruby 2.1.2.
def download
file_path = '/tmp/big_file.tar.gz' # 5 GB
send_file(file_path, buffer_size: 4096, stream: true)
end
If you are using send_file, it is ideal to use a front end proxy to pass off the responsibility of serving the file. You said you are using nginx in production, so:
In your production.rb file, uncomment config.action_dispatch.x_sendfile_header = 'X-Accel-Redirect'.
You will also have to change your nginx configuration to accommodate Rack::Sendfile. Its documentation is located here. The changes amount to adding:
proxy_set_header X-Sendfile-Type X-Accel-Redirect;
proxy_set_header X-Accel-Mapping /=/files/; # or something similar that doesn't interfere with your routes
to your existing location block and adding an additional location block that handles the X-Accel-Mapping that you added. That new location block might look like:
location ~ /files(.*) {
internal;
alias $1;
}
You will know it is working correctly when you ssh to your production server and curl -I the thin server (not nginx) and see a X-Accel-Redirect header. curl (no -I) directly to the thin server should not send the file contents.
You can see my recent struggle with nginx and send_file here.
I have an action, that generates a PDF files and save it in the /public/output.pdf.
When I set
config.serve_static_assets = false
this file can't be found.
What's wrong ?
From the documentation:
"config.serve_static_assets configures Rails itself to serve static
assets. Defaults to true, but in the production environment is turned
off as the server software (e.g. Nginx or Apache) used to run the
application should serve static assets instead. Unlike the default
setting set this to true when running (absolutely not recommended!) or
testing your app in production mode using WEBrick. Otherwise you won´t
be able use page caching and requests for files that exist regularly
under the public directory will anyway hit your Rails app."
Which means that if you set that to false Rails will not serve any assets from your public folder as it is assumed that a front-end web server (apache/nginx) will handle it. This lessons the load on Rails as the front-end server is much, much more efficient at serving files directly.
After testing, I came to this conclusion:
1) when using the command
rails s -e production
Rails will only serve the statics files. Any other file created after you compile your assets will not be found.
To handle this, you need to execute your application under a web server like Apache, Nginx or other. These web servers will serve this files for you.
This looks to be obvious, but not for a beginner.
I have a Sinatra app in a Rails app that serves a static asset from a directory. The app is mounted in the Rails routes like this:
mount BeanstalkdView::Server, :at => "/beanstalk"
When I run this locally it works fine, using Thin, but when I run it on my test server (Nginx/Passenger) the static assets behave strange. A request to a static file return 200 OK, but there is no content.
I tell Sinatra where my static files are via set :public_folder, "#{root}/resources" and in the template I load the static files, e.g. a CSS file with #{request.env['SCRIPT_NAME']}/css/file.css. I verified that both paths are correct.
That happens due to ::Rack::Sendfile middleware which is enabled by default in Rails 3.0.x in production (disabled by default in any environment since 3.1.x).
This middleware is really simple but yet powerful. When you pass ::Rack::File or ::Sinatra::StaticFile (or any other object) which respond to :path, this middlware adds X-SendFile (for Apache) or X-SendFile-Redirect (for NGinx) and does not sends actual body. So that Apache or NGinx will handle real file delivery. It's a good and most efficient way to serve static assets in production, however you may disable this middleware (if you don't want to mess with your Nginx/Apache config). Find and comment following config option in your config/environments/production.rb file:
config.action_dispatch.x_sendfile_header
this config option is used to instruct Sendfile middleware which header to set (do not do anything if not specified).
Aleksey V's answer helped me a lot. In the end I fixed this using the proper setting for Nginx in production.rb:
config.action_dispatch.x_sendfile_header = 'X-Accel-Redirect'
Make sure you restart your Rails app, Nginx and do a hard refresh in your browser to get the files.
For more info check out: http://jimneath.org/2011/04/05/rails-3-nginx-and-send_file.html.
I'm struggling with send_file with rails 3.0.9 running ruby 1.9, passenger 3.0.8 on apache on ubuntu lucid
The xsendfile module is installed and loaded into apache
root~# a2enmod xsendfile
Module xsendfile already enabled
Its symlinked correctly in mods-enabled
lrwxrwxrwx 1 root root 32 Aug 8 11:20 xsendfile.load -> ../mods-available/xsendfile.load
config.action_dispatch.x_sendfile_header = "X-Sendfile" is set in my production.rb
using send_file results in zero byte files being sent to the browser
filepath = Rails.root.join('export',"#{filename}.csv")
if File.exists?(filepath)
send_file filepath, :type => 'text/csv'
end
I believe the previous answer isn't the right way to go because, as far as I can tell, Apache isn't handling the downloads at all when this solution is applied, instead the rails process is. That's why the nginx directive, which shouldn't work, appears to. You get the same result by commenting out the config directive.
Another drawback (aside from tying up a rails process for too long) is that when the data streaming is handled by the rails process the response doesn't seem to send the content length header. So a user doesn't know how large the file they're downloading is, nor how long it will take (a usability problem).
I was able to get it to work by ensuring that mod_sendfile was properly included and loaded in my apache config, like so (this will be dependent on your apache install, etc.):
LoadModule xsendfile_module /usr/lib64/httpd/modules/mod_xsendfile.so
...
# enable mod_x_sendfile for offloading zip file downloads from rails
XSendFile on
XSendFilePath /
I can't get send_file(Model.attachment.path) to work.
It doesn't fail, instead, it sends a 0 byte size file to the client, the file names are correct though.
This problem started happening after I did a big migration from Rails 2.3.8 to 3.
There were a lot of other things that took place in this migration and I will try my best to detail all of them.
Distrubution change/Server Change. Rackspace RHEL5 to Linode Ubuntu 10.04LTS
Ruby version change, 1.8.6 -> 1.9.2
Rails version change, 2.3.8 -> 3.0.0
httpd platform change, apache2 -> nginx (However I tried on apache2 as well and it did not work).
I moved the attachments via ftp as they were not part of my git repositories so they were published via cap deploy, instead manual ftp remote(RHEL5) to local(Win7) then local(Win7) to remote(Ubuntu10).
I do know that FTPing does not retain the file permissions through the transfers, so what I've also done is mimicked the chmods that were seen on my previous servers so they are almost identical. (users/groups are different, set to root:root instead of olduser:olduser).
A snippet of the request to download a attachment from my production log.
Started GET "/attachments/replies/1410?1277105698" for 218.102.140.205 at 2010-09-16 09:44:31 +0000
Processing by AttachmentsController#replies as HTML
Parameters: {"1277105698"=>nil, "id"=>"1410"}
Sent file /srv/app/releases/20100916094249/attachments/replies/UE0003-Requisition_For_Compensation_Leave.doc (0.2ms)
Completed 200 OK in 78ms
Everything's okay. Let me also rule out local issues, I've tried downloading via Chrome on both Win7 and Ubuntu (on Vbox).
Let me also assure you that the path is indeed correct.
root#li162-41:/srv/app/current# tail /srv/app/releases/20100916094249/attachments/replies/UE0003-Requisition_For_Compensation_Leave.doc
#
#
%17nw
HQ��+1ae����
%33333333333(��QR���HX�"%%��#9
��#�p4��#P#��Unknown������������G��z �Times New Roman5��Symbol3&�
�z �Arial5&�
So to sum up the question, how do I get send_file to actually send files instead of fake 0 byte junk.
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 to
configure 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.
I've had similar issues with send_file() in the past, using send_data() instead saved me back then (e.g. send_data File.read(filename), :disposition => 'inline', :type => "some/mimetype")
On Rails 4, I realize my problem is that I deleted the temporary file which I've generated to send to user.
If I didn't delete the file, send_file works. I've not tested on thin but it works great on Passenger 5 as stand-alone server.