Possible bug with cached redirects and chunked encoding

[sfussenegger]

Hi all,

I have a problem using nginx as reverse proxy cache (in front of Jetty). 

Depending on the client, a redirect from cache takes either very long to complete or fails (curl: (18) transfer closed with outstanding read data remaining) - only chrome works as expected. 

It looks like a redirect from cache doesn't play nicely with "Transfer-Encoding: chunked". Using Wireshark, I've seen that no empty chunk follows the header after a cache hit. I'd bet that this is illegal (and handled differently in different clients - hence the different behavior).

Is this a known issue? Or is there a patch available? As a quick workaround, I've disabled caching of redirects.


some config snippets:

# 1st snippet
server {
  # snip
  proxy_cache  myapp;
  proxy_cache_valid  200 302 30m;
  proxy_cache_valid  301 1h;
  proxy_cache_use_stale  updating;
  proxy_cache_key  "$scheme$host$request_uri";
  add_header  X-Upstream-Cache-Status $upstream_cache_status;
}

# 2nd snippet
  location / {
    # snip
    proxy_pass  http://backend;
    proxy_set_header  X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header  Host $http_host;
    proxy_pass_header  Set-Cookie; 
  }

# 3rd snippet
http {
  # snip
  gzip  on;
  gzip_disable  msie6;

  proxy_cache_path   /tmp/nginx-cache levels=1:2 keys_zone=myapp:10m inactive=60m max_size=1000m;
}


First request to a cached resource:

$ curl -i http://local.example.com/script/all.js
HTTP/1.1 301 Moved Permanently
Server: nginx
Date: Wed, 13 Jan 2010 16:13:57 GMT
Transfer-Encoding: chunked
Connection: keep-alive
Location: http://www.local.example.com/script/all.js
X-Upstream-Cache-Status: MISS



Second request to a cached resource:

$ curl -i http://local.example.com/script/all.js
HTTP/1.1 301 Moved Permanently
Server: nginx
Date: Wed, 13 Jan 2010 16:15:02 GMT
Transfer-Encoding: chunked
Connection: keep-alive
Location: http://www.local.example.com/script/all.js
X-Upstream-Cache-Status: HIT

curl: (18) transfer closed with outstanding read data remaining


Request to backend server:

$ curl -i http://local.example.com:8082/script/all.js
HTTP/1.1 301 Moved Permanently
Date: Wed, 13 Jan 2010 16:33:15 GMT
Location: http://www.local.example.com/script/all.js
Content-Length: 0




Cheers, Stefan

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,40752,40752#msg-40752