Setting Cache-Control headers on js assets in RAILS 3.1

I check the headers on my production server as

    curl --head -H "Accept-Encoding: gzip" http://foo.heroku.com/assets/mobile.js

and I get back the following headers which suggest RAILS is not setting the cachecontrol headers.

HTTP/1.1 200 OK
Server: nginx/0.7.67
Date: Wed, 22 Jun 2011 12:01:55 GMT
Content-Type: application/javascript
Connection: keep-alive
Content-Md5: efb90436a465f8a73efb467109f745f3
Cache-Control: no-cache
Last-Modified: Wed, 22 Jun 2011 11:46:04 GMT
Etag: "efb90436a465f8a73efb467109f745f3"
X-Ua-Compatible: IE=Edge,chrome=1
X-Runtime: 0.001258
X-Content-Digest: 6493f457e9550773761bb1c2c52ec4cb44a19c19
X-Rack-Cache: stale, valid, store
X-Varnish: 16437361开发者_开发问答4
Age: 0
Via: 1.1 varnish
Content-Encoding: gzip

I'd like to get heroku's varnish cache caching the assets and only refreshing on git push. Any ideas on how to get this?

Brad

You have to add this in your environment/production.rb:

config.serve_static_assets = true
config.static_cache_control = "public, max-age=172800"

Camille's answer is right for Rails versions before 5.1

However, in Rails 5.1 config.static_cache_control will be deprecated. The code updated with the new available option should be:

config.serve_static_assets = true
config.public_file_server.headers = { 'Cache-Control' => 'public, max-age= 172800' }