Unexpected exception upon serializing continuation

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"};
}