OAuth with Digg API - ruby-on-rails

Question

I'm attempting to get Rails to play nice with the Digg API's OAuth. I'm using the oauth gem (ruby one, not the rails one).
My code looks approximately like this:
#consumer = OAuth::Consumer.new(API_KEY, API_SECRET,
:scheme => :header,
:http_method => :post,
:oauth_callback => "http://locahost:3000",
:request_token_url => 'http://services.digg.com/1.0/endpoint?method=oauth.getRequestToken',
:access_token_url => 'http://services.digg.com/1.0/endpoint?method=oauth.getAccessToken',
:authorize_url => 'http://digg.com/oauth/authorize')
#request_token = DiggController.consumer.get_request_token({
:oauth_callback => "http://xx.xxx.xxx.x:3000/digg/callback"
}, {
'Content-Type' => 'application/x-www-form-urlencoded'
})
session[:request_token] = #request_token.token
session[:request_token_secret] = #request_token.secret
redirect_to #request_token.authorize_url
Which is by-the-book in terms of what the gem documentation gave me. However, Digg spits a "400 Bad Request" error back at me when #consumer.get_request_token is called. I can't figure out what I'm doing wrong. Any ideas?
Edit: Code updated and Wireshark output added. My error is now "401 Authorization Required".
Output from Wireshark:
POST /1.0/endpoint?method=oauth.getRequestToken HTTP/1.1
Accept: */*
Connection: close
User-Agent: OAuth gem v0.3.6
Content-Type: application/x-www-form-urlencoded
Authorization: OAuth oauth_nonce="xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx",
oauth_callback="http%3A%2F%2Fxx.xxx.xxx.x%3A3000%2Fdigg%2Fcallback",
oauth_signature_method="HMAC-SHA1",
oauth_timestamp="1268687137",
oauth_consumer_key="xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx",
oauth_signature="xxx%2Bxxxxxxxxxxxxxxx%2Fxxxxxxx%3D", oauth_version="1.0"
Content-Length: 48
Host: services.digg.com
Content-Type=application%2fx-www-form-urlencoded
HTTP/1.1 401 Authorization Required
Date: Mon, 15 Mar 2010 21:05:37 GMT
Server: Apache
X-Powered-By: PHP/5.2.9-digg8
Cache-control: private
X-RateLimit-Current: 1
X-RateLimit-Max: 1000
X-RateLimit-Reset: 3600
X-Digg-Api-Version: 1.0
Accept-Ranges: bytes
Content-Length: 111
Keep-Alive: timeout=5, max=9998
Connection: Keep-Alive
Content-Type: text/xml;charset=utf-8
<?xml version="1.0" encoding="UTF-8"?>
<error code="5001" message="Invalid
signature" timestamp="1268687137"/>

Answer 1

Incidentally, the callback parameter should not be localhost:3000 but rather your public IP address (making sure to also open up port 3000 for external connections in your computer and/or router firewall(s)), or be left to the default (out-of-band.)
Examine the contents of the OAuth::Unauthorized exception which gets thrown (or use a sniffer such as tcpdump or Wireshark) to get additional details about the HTTP 400 error (they are probably having issues with some of your parameters.)