Google GData .Net OAuthUtil.GetAccessToken 400 Bad Request

Question

I'm trying generate an OAuth access token via the Google .Net GData Client Library. I've been using the instructions in http://code.google.com/apis/gdata/docs/auth/oauth.html as a guide and everything's been working up until I attempt calling OAuthUtil.GetAccessToken( parameters ) at which point I receive a "(400) Bad Request" web exception.

Unfortunately, it's not telling me anything about why it's a bad request. So, I'm kinda baffled about this. The only idea I have is that, because I'm using a localhost url it's not working (though I have registered the url in the Google API Console and it seemed to be okay to do so).

Any ideas what I'm doing wrong here and what I should be doing to make it right?

The OAuthParameters object is constructed like so (sensitive data is censored, hope that doesn't make it hard to answer):

BaseProperties:
    oauth_consumer_key:     <CLIENT_KEY>,
    oauth_nonce:            <NONCE>
    oauth_signature_method: HMAC-SHA1
    oauth_timestamp:        1330440325
    oauth_token:            <TOKEN>
    oauth_verifier:         <VERIFIER>
Callback:        "http://localhost:57381/subscription_auth.aspx?c=google.calendar"
ConsumerKey:     <CLIENT_KEY>
ConsumerSecret:  <CLIENT_SECRET>
ExtraProperties
    oauth_consumer_secret: <CLIENT_SECRET>
    scope:                 https://docs.google.com/calendar/feeds/
    oauth_callback:        http://localhost:57381/subscription_auth.aspx?c=google.calendar
Nonce:           <NONCE>
Scope:           "https://docs.google.com/calendar/feeds/"
Signature:       NULL
SignatureMethod: "HMAC-SHA1"
Timestamp:       "1330440325"
Token:           <TOKEN>
TokenSecret:     NULL  -- No Token Secret was returned from the callback.
Verifier:        <VERIFIER>

This translates into headers for the web response which are like so:

Authorization: OAuth oauth_version="1.0",
oauth_nonce=<NONCE>,
oauth_timestamp="1330441324",
oauth_consumer_key=<CLIENT_KEY>,
oauth_verifier=<VERIFIER>,
oauth_token=<TOKEN>,
oauth_signature_method="HMAC-SHA1",
oauth_signature=<SIGNATURE>

(line breaks added for readability)

NOTE: The above redacted values are encoded correctly where relevant by the GData code.

And the request uri is: https://www.google.com/accounts/OAuthGetAccessToken

The error's happening at line 186 as per the class located here: http://code.google.com/p/google-gdata/source/browse/trunk/clients/cs/src/core/oauthutil.cs?r=1123

Answer 1

This may be completely unrelated but the URL you have specified in your scope

https://docs.google.com/calendar/feeds/

returns a 404 error

I think you should be using the following instead:

http://www.google.com/calendar/feeds/default/

or possibly http://www.google.com/calendar/feeds/default/owncalendars/full