Unexpected exception upon serializing continuation - google-docs-api

Question

I get this error: Unexpected exception upon serializing continuation (not much help)
It is caused by the FetchUrlApp.fetch(); call. I akm using Google Apps Script for Sites, not Google Spreadsheets. The code works in the original instance but as soon as I copy and paste the code into a new project I get the above error message. I am accessing Google Docs APIs. I have read on other forums that I need authorization but I have been unable to gain the right authorization for the code to work. No prompt ever pops up when I run a copy of the code for the first time.
Code exert:
var oauthConfig = UrlFetchApp.addOAuthService("docs");
oauthConfig.setAccessTokenUrl("https://www.google.com/accounts/OAuthGetAccessToken");
oauthConfig.setRequestTokenUrl("https://www.google.com/accounts/OAuthGetRequestToken?scope=https://docs.google.com/feeds/");
oauthConfig.setAuthorizationUrl("https://www.google.com/accounts/OAuthAuthorizeToken");
oauthConfig.setConsumerKey(_consumerKey_);
oauthConfig.setConsumerSecret(_consumerSecret_);
var requestData3 = {
"method": "GET",
"headers": {"GData-Version": "3.0"},
"oAuthServiceName": "docs",
"oAuthUseToken": "always",
};
var url = "https://docs.google.com/feeds/" + userName + "/private/full/-/mine";
var result = UrlFetchApp.fetch(url, requestData3); //error occurs, any thoughts?
Thank you in advance,
James Krimm

Answer 1

You have to set both consumerKey and consumerSecret to "anonymous" in order to trigger the 3-legged OAuth process:
oauthConfig.setConsumerKey("anonymous");
oauthConfig.setConsumerSecret("anonymous");
Replace your two lines with these and the authorization popup dialog will show up, allowing the user to grant access to its documents.

Answer 2

What I would suggest is to write a special function that does nothing else than call the Oauth process and call it from the script editor once.
As an example, here is the one I have used recently to make the authorize popup appear :
function authorize(){
// function to call from the script editor to authorize googleOauth
var id=mailtemplatedoc
var url = 'https://docs.google.com/feeds/';
var doc = UrlFetchApp.fetch(url+'download/documents/Export? exportFormat=html&format=html&id='+id,
googleOAuth_('docs',url)).getContentText();
}
EDIT : And the missing part I had forgotten :
function googleOAuth_(name,scope) {
var oAuthConfig = UrlFetchApp.addOAuthService(name);
oAuthConfig.setRequestTokenUrl("https://www.google.com/accounts/OAuthGetRequestToken?scope="+scope);
oAuthConfig.setAuthorizationUrl("https://www.google.com/accounts/OAuthAuthorizeToken");
oAuthConfig.setAccessTokenUrl("https://www.google.com/accounts/OAuthGetAccessToken");
oAuthConfig.setConsumerKey('anonymous');
oAuthConfig.setConsumerSecret('anonymous');
return {oAuthServiceName:name, oAuthUseToken:"always"};
}