nginx: How to keep double slashes in urls

I had a similar issue with nginx+passenger (for Ruby on Rails / Rack / etc.), and I confirm that by default, multiple slashes are collapsed (in both PATH_INFO and REQUEST_URI).

Adding merge_slashes off; in the server context of the nginx configuration fixed it (I now see multiple slashes alright).

Also, make sure you don't have a trailing slash in the proxy_pass line!

• GOOD: proxy_pass http://localhost:3000;

• BAD: proxy_pass http://localhost:3000/;

syntax: merge_slashes [on|off]
default: merge_slashes on
context: http, server

You must use: merge_slashes off;