Acquire Twitter request token failed

I followed the instruction at http://dev.twitter.com/pages/auth#request-token, and developed a c# class to do the OAuth authorization. I used the parameters on the page, and the output signature base string and signature match that on the page. So I think the algorithm part is correct. Then I replaced the parameters with the ones in my twitter application, but I failed to acquire the request token from Twitter service. And the response data is "Failed to validate oauth signature and token".

Here's the request I send (I used http, instead of https for debug):

POST http://api.twitter.com/oauth/request_token HTTP/1.1
Content-Type: application/x-www-form-urlencoded
Authorization: OAuth oauth_callback="http%3A%2F%2Flocalhost%3A3005%2Fthe_dance%2Fprocess_call开发者_开发知识库back%3Fservice_provider_id%3D11", oauth_consumer_key="GDdmIQH6jhtmLUypg82g", oauth_nonce="QP70eNmVz8jvdPevU3oJD2AfF7R7odC2XJcn4XlZJqk", oauth_signature_method="HMAC-SHA1", oauth_timestamp="1272323042", oauth_version="1.0", oauth_signagure="IP%2FEEoc4tKdiobM%2FKH5cPK69cJM%3D"
Host: api.twitter.com
Proxy-Connection: Keep-Alive

And here's the response:

HTTP/1.1 401 Unauthorized
Connection: Keep-Alive
Connection: Proxy-Support
Content-Length: 44
Via: 1.1 APS-PRXY-09
Expires: Tue, 31 Mar 1981 05:00:00 GMT
Date: Fri, 08 Apr 2011 05:47:20 GMT
Content-Type: text/html; charset=utf-8
Server: hi
Proxy-Support: Session-Based-Authentication
Status: 401 Unauthorized
X-Transaction: 1302241640-40339-46793
Last-Modified: Fri, 08 Apr 2011 05:47:20 GMT
X-Runtime: 0.01519
Pragma: no-cache
X-Revision: DEV
Cache-Control: no-cache, no-store, must-revalidate, pre-check=0, post-check=0
Set-Cookie: k=207.46.55.29.1302241640766556; path=/; expires=Fri, 15-Apr-11 05:47:20 GMT; domain=.twitter.com
Set-Cookie: guest_id=13022416407746962; path=/; expires=Sun, 08 May 2011 05:47:20 GMT
Set-Cookie: _twitter_sess=BAh7CDoPY3JlYXRlZF9hdGwrCEiBpjMvAToHaWQiJWMzMTViOGZiNDkzMDRi%250ANjNhMmQwYmVkZDBhNTc2NTc4IgpmbGFzaElDOidBY3Rpb25Db250cm9sbGVy%250AOjpGbGFzaDo6Rmxhc2hIYXNoewAGOgpAdXNlZHsA--177afd5c0f6fe30005ab9a9412e6f85ab03cbfa7; domain=.twitter.com; path=/; HttpOnly
Vary: Accept-Encoding

Failed to validate oauth signature and token

This is how I generate the normalized parameters:

string.Join("&", (from d in this.BuildParameterDict()
                  select string.Format("{0}={1}", OAuthEncoding.Encode(d.Key), OAuthEncoding.Encode(d.Value))))

The BuildParameterDict method will sorted build a list with: parameters from query string; parameters from body; parameters sepcific to 'oauth', except the 'oauth_signature'.

Then the signature base string is generated by:

            StringBuilder sb = new StringBuilder();

            sb.Append(OAuthEncoding.Encode(this._request.Method));
            sb.Append('&');
            sb.Append(OAuthEncoding.Encode(this.GetNormalUri()));
            sb.Append('&');
            sb.Append(OAuthEncoding.Encode(this.GetNormalParameters()));

This is the generated base string with parameters from the above page:

POST&https%3A%2F%2Fapi.twitter.com%2Foauth%2Frequest_token&oauth_callback%3Dhttp%253A%252F%252Flocalhost%253A3005%252Fthe_dance%252Fprocess_callback%253Fservice_provider_id%253D11%26oauth_consumer_key%3DGDdmIQH6jhtmLUypg82g%26oauth_nonce%3DQP70eNmVz8jvdPevU3oJD2AfF7R7odC2XJcn4XlZJqk%26oauth_signature_method%3DHMAC-SHA1%26oauth_timestamp%3D1272323042%26oauth_version%3D1.0

which is identical to the string on that page.

Your oauth signature is listed as "oauth_signagure" in your request.

oAuth parameters has to be sorted before sending, but signature has to be at the end of the authorization request.(9.1.1 in http://oauth.net/core/1.0/#anchor14)

You may also need to specify a realm="/oauth/request_token". It's optional, but as I remember correctly Twitter wants this one for a request token.

If you can add your code we might find what's going on, as you might not be building your request and key for signature hashing correctly.