Message "X-Accel-Mapping header missing" in Nginx error log
I am running a Rails 3 site on Ubuntu 8.04 with Nginx 1.0.0 and Passenger 3.0.7.
In my Nginx error.log I started seeing the message X-Accel-Mapping header missing
quite a lot. Googling lead me to the docs of Rack::Sendfile
and to the Nginx docs.
Now, my app can be accessed through several domains and I am using send_file
in my app to deliver some files specific to the domain they are requested from, e.g., if you come to domain1.com/favicon.ico
I look up the favicon in at public/websites/domain1/favicon.ico
.
This works fine a开发者_开发问答nd I don't think I need/want to get Nginx involved and create some private area where I store those files, as the samples in the Rack::Sendfile
docs suggest.
How can I get rid of the error message?
this message means that Rack::Sendfile
disabled X-Accel-Redirect
for you, because you have missing configuration for it in nginx.conf...
I'm using Nginx + Passenger 3 + Rails 3.1.
Gathered information from this pages I've figured it out:
http://wiki.nginx.org/X-accel
http://greenlegos.wordpress.com/2011/09/12/sending-files-with-nginx-x-accel-redirect
http://code.google.com/p/substruct/source/browse/trunk/gems/rack-1.1.0/lib/rack/sendfile.rb?r=355
Serving Large Files Through Nginx via Rails 2.3 Using x-sendfile
I have controller which maps /download/1
requests to storage files which have their own directory structure, like this: storage/00/00/1
, storage/01/0f/15
etc. So I need to pass this through Rails, but then I need to use send_file
method which will use X-Accel-Redirect
to send the final file to the browser through nginx directly.
Within the code I have this:
send_file(
'/var/www/shared/storage/00/00/01',
:disposition => :inline,
:filename => @file.name # an absolute path to the file which you want to send
)
I replaced the filename for this example purposes
Now I had to add these lines to my nginx.conf
:
server {
# ...
passenger_set_cgi_param HTTP_X_ACCEL_MAPPING /var/www/shared/storage/=/storage/;
passenger_pass_header X-Accel-Redirect;
location /storage {
root /var/www/shared;
internal;
}
# ...
}
The path /storage
is not visible from outside world, it is internal only.
Rack::Sendfile
gets the header X-Accel-Mapping
, extracts the path from it and replaces /var/www/shared/storage
with /storage...
. Then it spits out the modified header:
X-Accel-Redirect: /storage/00/00/01
which is then processed by nginx.
I can see this works correctly as the file is downloaded 100x faster than before and no error is shown in the logs.
Hope this helps.
We used the similar technique as NoICE described, but i replaced the "hard-coded" directory containing all the files with the regular expression describing the folder containing the folders containing the files.
Sounds hard, yeah? Just take a look on these (/etc/nginx/sites-available/my.web.site
):
location /assets/(.+-[a-z0-9]+\.\w+) {
root /home/user/my.web.site/public/assets/$1;
internal;
}
location /images/(.+)(\?.*)? {
root /home/user/my.web.site/public/images/$1;
internal;
}
This should be used with this check:
location / {
# ...
if (-f $request_filename) {
expires max;
break;
}
# ...
}
to prevent the statics from Rails processing.
I did by this manual
https://mattbrictson.com/accelerated-rails-downloads
my server sends file path /private_upload/file/123/myfile.txt
, the file is in /data/myapp-data/private_upload/file/123/myfile.txt
# Allow NGINX to serve any file in /data/myapp-data/private_upload
# via a special internal-only location.
location /private_upload {
internal;
alias /data/myapp-data/private_upload;
}
# ---------- BACKEND ----------
location @backend
{
limit_req zone=backend_req_limit_per_ip burst=20 nodelay;
proxy_pass http://backend;
proxy_set_header X-Sendfile-Type X-Accel-Redirect;
proxy_set_header X-Accel-Mapping /=/; # this header is required, it does nothing
include /etc/nginx/templates/myapp_proxy.conf;
}
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