It is often convenient to reverse proxy CouchDB at a url like /couch. Unfortunately, while CouchDB will work perfectly in this situation, Futon cannot handle it as jquery.couch.js uses absolute URLs to access all CouchDB functions.
I've attached a small patch that fixes this problem by:
1. Adding a urlPrefix attribute to $.couch which it uses to construct its URLs.
2. Adding logic to the futon.js constructor that figures out a suitable prefix and sets $.couch.urlPrefix to use this.
Any client code that makes use of $.couch will need to do something similar. Since only the application and the adminstrator will know what the prefix should be or how to deduce it, I didn't really know of a better way to handle this.