I have Rails application (Redmine) which works with Nginx. If I am clicking on any attachment my browser (firefox, ie, chrome) ask me to download file. But if I am clicking on txt-type attachment my browser open this file in the browser.

As I understand it is task of Nginx to decide - open file in the browser or to download it. How can I setup it?


Default type for txt extension is text/plain. This behavior is described in mime.types file. Use http://nginx.org/en/docs/http/ngx_http_core_module.html#default_type or http://nginx.org/en/docs/http/ngx_http_core_module.html#types to override it (maybe set to application/octet-stream).


Changing the Content-Type of .txt files may work, but it's a somewhat risky way to solve this problem, because you can't guarantee 100% that the user's browser will respond how you expect. And furthermore, it's misleading to label a .txt file as a binary file.

Instead, I suggest using the standard way to force a browser to download rather than display the file, which is to use the Content-Disposition header with a value of attachment (RFC 2183, see also RFC 2616).

For example, this nginx location block will send down such a header with .txt files under the /downloads/ URI and thus they will be forced to download:

location ~ ^/downloads/.*\.txt$ {
  add_header Content-Disposition "attachment";

So you could add other appropriate matching, etc, appropriate to your configuration.

  • 3
    It seems to be the best solution.
    – Vadim
    Feb 28 '12 at 17:17
  • But Content-Disposition hack in chromium browser can start saying bad words into console and even stop downloading any files from page. It says thinhgs (with yellow triangles) like: "Resource interpreted as Document but transferred with MIME type image/png:"
    – Nakilon
    May 24 '13 at 16:00

You need to extract location for downloadable file and set their content-type as application/octet-stream.

We have following location on our service for downloadable promomaterial (which includes pdfs, images and some docs, but I'm sure it will work with txt files as well):

location /promomaterial/download/ {
         add_header Content-Type application/octet-stream;

Every browser we've tried downloads all files from this location instead of trying to display them.

  • 4
    Using "add_header" it's absolutely wrong, use "default_type" instead: location /smth/ { default_type application/octet-stream;; } Oct 25 '15 at 8:12
  • @OlegNeumyvakin Why is default_type better than add_header?
    – user193661
    Aug 17 '17 at 22:49
  • 3
    @user193661 Because "add_header" it's litterally adds new header "Content-Type", so in response you can get two "Content-Type" headers what can lead to strange behaviour of HTTP clients. "default_type" is set(overwrite) single "Content-Type" header in response. Aug 18 '17 at 7:46

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