As illustrated in this Wireshark packet dump, lines 53ff, any OAuth request with a non-percent-encoded URL as the realm will return a 500 error:
Erlang stacktrace is similar to:
[error] [<0.189.0>] function_clause error in HTTP request [Wed, 27 Apr 2011 23:31:46 GMT] [info] [<0.189.0>] Stacktrace:
] [Wed, 27 Apr 2011 23:31:46 GMT] [info] [<0.189.0>] 127.0.0.1 - - 'PUT'
Chatted with benoitc today and he suggested this may be because the realm is not being properly encoded before being passed on.
By default, some OAuth libraries such as python's popular oauth2 library always set the realm of a request to the URL of the resource being accessed, such as http://localhost:5984/ . (In fact, oauth2 library does not support overriding this setting.) The OAuth spec @ http://oauth.net/core/1.0/ also shows realms specified as URLs. RFC5849 states "The OPTIONAL "realm" parameter MAY be added and interpreted per [RFC2617] section 1.2.", which in turn says the realm is any quoted-string.
It seems that this may already be fixed in trunk simply because trunk has a newer version of the upstream erlang-oauth.
A JS test could be added in futon to validate this by modifying function oauthRequest to accept a realm parameter, then passing that down to OAuth.getAuthorizationHeader on line 56.