*** SMTP XOAUTH for ruby's Net::SMTP ***

Based on http://code.google.com/apis/gmail/oauth/protocol.html


Requires a signed input base string passed in for password secret - the oauth gem is helpful in creating this

Leaves the username as a parameter to maintain compatibility with other auth_ methods

#todo - add functions to more easily create this string given the user's email address, token and secret
#todo - figure out how to make gems and such properly


**  USAGE EXAMPLE **

Basically all this library provides is the new :auth => :oauth  argument to Net::SMTP (see example below)

To get something working out with minimal work, use Google's Python commandline script to generate a valid auth_string
http://code.google.com/p/google-mail-xoauth-tools/wiki/XoauthDotPyRunThrough  and use the Pony mail code below
to send a message (gem install pony)


The auth_string below is what an "initial client request" looks like before Base64 encoding - 
this is what's passed to the auth_xoauth function as a string.  

<pre>

require 'smtp-xoauth'
require 'pony'

# to see this working get yourself a valid auth_string using google's xoauth.py utility
auth_string = 'GET https://mail.google.com/mail/b/youremail@gmail.com/smtp/ oauth_consumer_key="oftenyourdomain.com",oauth_nonce="6762341348542013497",oauth_signature="CqU4ov0ashDqMrWXw6yKWTbbjE%3D",oauth_signature_method="HMAC-SHA1",oauth_timestamp="1270697273",oauth_token="1%2F3cJbEP_tmYo0svadifjadsfWpQgBP6-NVeeBHDUXOek",oauth_version="1.0"'


Pony.mail( :from => "youremail@gmail.com", 
           :to => "destination@anywhere.com", 
           :body => "no big deal", 
           :subject => "oauth'ed message", 
           :content_type => 'text/plain', 
           :via => :smtp, 
           :smtp => {
          	  :host   => 'smtp.gmail.com',
              :port   => '587',
              :tls    => true,
              :user   => 'gmailusername',
              :password   => auth_string,
              :auth   => :oauth
           })


</pre>

To rebuild the gem after mucking with the code, just do "rake gem"
Contact alvin via github if you have any suggestions or contributions.