IMAP using OAuth2 on App Engine - google-app-engine

Question

I'm trying to implement a service on App Engine that interacts with an Gmail account using OAuth2, Java 7 and App Engine SDK 1.8.2. The problem being encountered is via the use of sample code provided by https://code.google.com/p/google-mail-oauth2-tools/wiki/JavaSampleCode the Security provider does not appear to be detected on a node although works locally fine. The code provided by the link before has been modified to be initiated by a servlet with sample code:
import java.io.IOException;
import java.security.Provider;
import java.security.Security;
import java.util.Properties;
import javax.mail.Session;
import javax.mail.URLName;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.google.code.samples.oauth2.OAuth2SaslClientFactory;
import com.sun.mail.imap.IMAPSSLStore;
import com.sun.mail.imap.IMAPStore;
import com.sun.mail.smtp.SMTPTransport;
public class RunnerServlet extends HttpServlet
{
public void doGet( HttpServletRequest request, HttpServletResponse response ) throws ServletException, IOException
{
String email = request.getParameter( "email");
String oauthToken = request.getParameter( "oauthToken");
initialize();
try
{
IMAPStore imapStore = connectToImap("imap.gmail.com",
993,
email,
oauthToken,
true);
System.out.println("Successfully authenticated to IMAP.\n");
SMTPTransport smtpTransport = connectToSmtp("smtp.gmail.com",
587,
email,
oauthToken,
true);
System.out.println("Successfully authenticated to SMTP.");
}
catch( Exception e )
{
e.printStackTrace(); //To change body of catch statement use File | Settings | File Templates.
throw new RuntimeException( e );
}
}
public static final class OAuth2Provider extends Provider {
private static final long serialVersionUID = 1L;
public OAuth2Provider() {
super("Google OAuth2 Provider", 1.0,
"Provides the XOAUTH2 SASL Mechanism");
put("SaslClientFactory.XOAUTH2",
"com.google.code.samples.oauth2.OAuth2SaslClientFactory");
}
}
public static void initialize() {
Security.addProvider(new OAuth2Provider());
}
public static IMAPStore connectToImap(String host, int port,
String userEmail, String oauthToken, boolean debug)
throws Exception {
Properties props = new Properties();
props.put("mail.imaps.sasl.enable", "true");
props.put("mail.imaps.sasl.mechanisms", "XOAUTH2");
props.put(OAuth2SaslClientFactory.OAUTH_TOKEN_PROP, oauthToken);
Session session = Session.getInstance(props);
session.setDebug(debug);
session.getProperties().put("mail.imaps.sasl.enable", "true");
session.getProperties().put("mail.imaps.sasl.mechanisms", "XOAUTH2");
session.getProperties().put(OAuth2SaslClientFactory.OAUTH_TOKEN_PROP, oauthToken);
final URLName unusedUrlName = null;
IMAPSSLStore store = new IMAPSSLStore(session, unusedUrlName);
final String emptyPassword = "";
store.connect(host, port, userEmail, emptyPassword);
return store;
}
public static SMTPTransport connectToSmtp(String host, int port,
String userEmail, String oauthToken, boolean debug)
throws Exception {
Properties props = new Properties();
props.put("mail.smtp.starttls.enable", "true");
props.put("mail.smtp.starttls.required", "true");
props.put("mail.smtp.sasl.enable", "true");
props.put("mail.smtp.sasl.mechanisms", "XOAUTH2");
props.put(OAuth2SaslClientFactory.OAUTH_TOKEN_PROP, oauthToken);
Session session = Session.getInstance(props);
session.setDebug(debug);
final URLName unusedUrlName = null;
SMTPTransport transport = new SMTPTransport(session, unusedUrlName);
// If the password is non-null, SMTP tries to do AUTH LOGIN.
final String emptyPassword = null;
transport.connect(host, port, userEmail, emptyPassword);
return transport;
}
}
The IMAP debug trace is:
DEBUG IMAPS: mail.imap.fetchsize: 16384
DEBUG IMAPS: mail.imap.ignorebodystructuresize: false
DEBUG IMAPS: mail.imap.statuscachetimeout: 1000
DEBUG IMAPS: mail.imap.appendbuffersize: -1
DEBUG IMAPS: mail.imap.minidletime: 10
DEBUG IMAPS: enable SASL
DEBUG IMAPS: SASL mechanisms allowed: XOAUTH2
DEBUG IMAPS: trying to connect to host "imap.gmail.com", port 993, isSSL true
* OK Gimap ready for requests from xxx.xxx.xxx.xxx ZZZZZZZZZ
A0 CAPABILITY
* CAPABILITY IMAP4rev1 UNSELECT IDLE NAMESPACE QUOTA ID XLIST CHILDREN X-GM-EXT-1 XYZZY
A0 OK Thats all she wrote! ZZZZZZZZZ
DEBUG IMAPS: AUTH: XOAUTH
DEBUG IMAPS: AUTH: XOAUTH2
DEBUG IMAPS: protocolConnect login, host=imap.gmail.com, user=som...#gmail.com, password=<non-null>
DEBUG IMAPS: SASL authentication command trace suppressed
DEBUG IMAPS: SASL Mechanisms:
DEBUG IMAPS: XOAUTH2
DEBUG IMAPS:
DEBUG IMAPS: No SASL support
DEBUG IMAPS: SASL authentication failed
DEBUG IMAPS: LOGIN command trace suppressed
DEBUG IMAPS: LOGIN command result: A1 NO Empty username or password. ZZZZZZZZZ
DEBUG IMAPS: trying to connect to host "imap.gmail.com", port 993, isSSL true
* OK Gimap ready for requests from xxx.xxx.xxx.xxx YYYYYYYYYY
A0 CAPABILITY
* CAPABILITY IMAP4rev1 UNSELECT IDLE NAMESPACE QUOTA ID XLIST CHILDREN X-GM-EXT-1 XYZZY SASL-IR AUTH=XOAUTH AUTH=XOAUTH2
A0 OK Thats all she wrote! YYY
DEBUG IMAPS: AUTH: XOAUTH
DEBUG IMAPS: AUTH: XOAUTH2
DEBUG IMAPS: protocolConnect login, host=imap.gmail.com, user=som...#gmail.com, password=<non-null>
DEBUG IMAPS: SASL authentication command trace suppressed
DEBUG IMAPS: SASL Mechanisms:
DEBUG IMAPS: XOAUTH2
DEBUG IMAPS:
DEBUG IMAPS: No SASL support
DEBUG IMAPS: SASL authentication failed
DEBUG IMAPS: LOGIN command trace suppressed
DEBUG IMAPS: LOGIN command result: A1 NO Empty username or password. YYYYYYYYYY
java.lang.RuntimeException: javax.mail.AuthenticationFailedException: Empty username or password. YYYYYYYYYY
This problem only occurs on a deployed node. Ensured that the provider was correct path and installed and using the latest versions of App Engine SDK that facilitates the IMAP and SMTP sockets. Triggering has been attempted via sample servlet and task on task queue.
Thank you for assistance in advance.

Answer 1

I've the same problem than you...
I've been researching, and I think the session isn't instantiated correctly. I attached a picture that shows the difference.
At the top of the image shows the contents of the variable "props" which is the same values for the AppEngine project (left image) that the project Normal(right image).
The down images shows the contents of the Session variable, and within this, the contents of the variables Properties. Like you can see in the left case, is null. But in the right case have values.
Here is the image: http://ricorrico.comoj.com/misc/img2.jpg
It really is a bug, is there any workaround?
Thank you very much in advance.
Regards!

Answer 2

Not sure if you are still running into this issue, but #user2606850 was very close to the solution. Initializing the session with the properties set does not properly initialize the session.
BUT adding the right properties AFTER the Session is created, WORKS !
Properties props = new Properties();
Session session = Session.getInstance(props);
props = session.getProperties();
props.put("mail.imaps.sasl.enable", "true");
props.put("mail.imaps.sasl.mechanisms", "XOAUTH2");
IMAPSSLStore store = new IMAPSSLStore(session, unusedUrlName);
...
Tested an proven to work deployed to AppEngine.