nginx + SslRequirement + mongrel cluster = infinite redirect loop

I'm getting an infinite redirect loop after adding SSL support to my site. I'm using the "SslRequirement" plugin.

The symptoms I'm seeing are, any action that has "ssl_required" enabled, and any URL I type in manually that has https at the front, goes into an infinite loop, with the following in the development.log file, 开发者_运维问答over and over until the browser catches the redirect loop and stops the loading of the page ("/admins/index" is the action in this example, but it happens with any action):

Processing AdminsController#index (for 127.0.0.1 at 2010-08-13 13:50:16) [GET]
  Parameters: {"action"=>"index", "controller"=>"admins"}
Redirected to https://localhost/admins
Filter chain halted as [:ensure_proper_protocol] rendered_or_redirected.
Completed in 0ms (DB: 0) | 302 Found [http://localhost/admins]

At first I thought there was some kind of problem where I had to make ALL of my actions "ssl_allowed" - so I tried that, but to no avail.

IF I remove the use of SslRequirement, and remove any "ssl_required/ssl_allowed" references, then https works fine - so it's the redirect in actions from http to https that seems to be the issue.

Any clues?

Answer found here:

http://www.hostingrails.com/SSL-Redirecting-not-working

Short version is, I added the following line to the SSL vhost in my nginx config:

proxy_set_header X_FORWARDED_PROTO https;

Detailed version is:

Basically the issue came down to the nginx server not passing the fact that the source request was an HTTPS protocol on to the Mongrel cluster. This caused the call to "request.ssl?" inside the SslRequirement plugin to ALWAYS return false.

So, when this returned as false, the "ensure_proper_protocol" would re-issue the action over https, which would check "request.ssl?", which would return "false", which would re-issue the action over https, which would check "request.ssl?", which would return "false", which would re-issue the action over https, which would check "request.ssl?", which would return "false", which would re-issue the action over https, which would check "request.ssl?", which would return "false", which would re-issue the action over https ...

...you get the idea. The mongrel cluster NEVER thought the request was over the HTTPS protocol, so it redirected forever. A small change in the nginx config to correct this, and BAM-O: problem solved.