Google's ClientLogin authentication implementation for Node.js

Requires at least nodejs 0.4.1

Properties:
  errors: That is an object, filled with the possible error messages.
  accountTypes: An object, where you can set the type of account to request authorization for.
    properties are: google, hosted, hostedOrGoogle
    default is hostedOrGoogle

Events:
  login: emitted when login was success
  error: emitted when an error occured. Has two parameters, the response object and the received data
  You can access to their names via constants: GoogleClientLogin.events.login or GoogleClientLogin.events.error
  or you can use 'login' and 'error' as string.

Methods:
  login
    Starts the login process. It has one optional parameter, which should be an object with two properties:
      logincaptcha, logintoken.
      The logincaptcha is the user's answer to the captcha question
      You will receive the logintoken if the login failed and the CaptchaRequired error code arrived
    You must pass both the logincaptcha and logintoken if you must pass a captcha challange

  getAuthId
    Returns the value of the authId key from the response. If the login was success you will need to use this value to perform additional requests. You must put it into a the Authorization header like this:
      'Authorization': 'GoogleLogin auth=' + googleAuth.getAuthId(),

  getSID
    Returns the value of SID key from the response.

  getLSID
    Returns the value of LSID key from the response.

  isCaptchaRequired
    If the login was not success and the user need to pass a captcha challenge this method will return true

  getCaptchaUrl
    Url of the captcha image

  getCaptchaToken
    You will need to pass it back to the google with the user's answer to the captcha if the login failed and captcha authentication required.

  getError
    If the login was not success, google will send back an error code what you can get with this method


After the login was success, you should use the AuthId in each of your requests, see example below

http://code.google.com/apis/gdata/faq.html#clientlogin
list of services:


Name                                                 |name in googleclientlogin module     |value
-----------------------------------------------------|-------------------------------------|---------------
Google Adwords APIs:                                 |adwords:                             |'adwords'
-----------------------------------------------------|-------------------------------------|---------------
Google Analytics Data APIs:                          |analytics:                           |'analytics'
-----------------------------------------------------|-------------------------------------|---------------
Google Apps APIs (Domain Information & Management):  |apps:                                |'apps'
-----------------------------------------------------|-------------------------------------|---------------
Google Base Data API:                                |base:                                |'gbase'
-----------------------------------------------------|-------------------------------------|---------------
Google Sites Data API:                               |sites:                               |'jotspot'
-----------------------------------------------------|-------------------------------------|---------------
Blogger Data API:                                    |blogger:                             |'blogger'
-----------------------------------------------------|-------------------------------------|---------------
Book Search Data API:                                |book:                                |'print'
-----------------------------------------------------|-------------------------------------|---------------
Calendar Data API:                                   |calendar:                            |'cl'
-----------------------------------------------------|-------------------------------------|---------------
Google Code Search Data API:                         |codesearch:                          |'codesearch'
-----------------------------------------------------|-------------------------------------|---------------
Contacts Data API:                                   |contacts:                            |'cp'
-----------------------------------------------------|-------------------------------------|---------------
Documents List Data API:                             |docs:                                |'writely'
-----------------------------------------------------|-------------------------------------|---------------
Finance Data API:                                    |finance:                             |'finance'
-----------------------------------------------------|-------------------------------------|---------------
Gmail Atom feed:                                     |mail:                                |'mail'
-----------------------------------------------------|-------------------------------------|---------------
Health Data API:                                     |health:                              |'health'
-----------------------------------------------------|-------------------------------------|---------------
Health Data API H9 Sandbox                           |weaver:                              |'weaver'
-----------------------------------------------------|-------------------------------------|---------------
Maps Data APIs:                                      |maps:                                |'local'
-----------------------------------------------------|-------------------------------------|---------------
Picasa Web Albums Data API:                          |picasaweb:                           |'lh2'
-----------------------------------------------------|-------------------------------------|---------------
Sidewiki Data API:                                   |sidewiki:                            |'annotateweb'
-----------------------------------------------------|-------------------------------------|---------------
Spreadsheets Data API:                               |spreadsheets:                        |'wise'
-----------------------------------------------------|-------------------------------------|---------------
Webmaster Tools API:                                 |webmastertools:                      |'sitemaps'
-----------------------------------------------------|-------------------------------------|---------------
YouTube Data API:                                    |youtube:                             |'youtube'
-----------------------------------------------------|-------------------------------------|---------------
C2DM Push Notification Service:                      |c2dm:                                |'ac2dm'
-----------------------------------------------------|-------------------------------------|---------------
Google Reader Data API (unofficial):                 |reader:                              |'reader'
-----------------------------------------------------|-------------------------------------|---------------
Google Voice API (unoffical):                        |voice:                               |'grandcentral'


How to use:

var GoogleClientLogin = import('googleclientlogin').GoogleClientLogin;
var googleAuth = new GoogleClientLogin({
  email: 'yourmail@gmail.com',
  password: 'yourpassword',
  service: 'contacts',
  accountType: GoogleClientLogin.accountTypes.google
});
googleAuth.on(GoogleClientLogin.events.login, function(){
  // do things with google services
  require('https').request({
    host: 'www.google.com',
    port: 443,
    path: path,
    method: 'GET',
    headers: {
      'Authorization': 'GoogleLogin auth=' + googleAuth.getAuthId(),
      ...
    }
  });
});
googleAuth.on(GoogleClientLogin.events.error, function(e) {
    switch(e.message) {
      case GoogleClientLogin.errors.loginFailed:
        if (this.isCaptchaRequired()) {
          requestCaptchaFromUser(this.getCaptchaUrl(), this.getCaptchaToken());
        } else {
          requestLoginDetailsAgain();
        }
        break;
      case GoogleClientLogin.errors.tokenMissing:
      case GoogleClientLogin.errors.captchaMissing:
        throw new Error('You must pass the both captcha token and the captcha')
        break;
    }
    throw new Error('Unknown error');
  // damn..
});
googleAuth.login();
