public class OAuth2

Public Class OAuth2

using System;
using System.Collections.Specialized;
using MailBee;
using MailBee.ImapMail;
using DotNetOpenAuth.OAuth2;

class Sample
{
    static string GetAccessToken(string clientID, string clientSecret, string key)
    {
        UserAgentClient consumer;
        IAuthorizationState grantedAccess;

        // Second: Fetch Access Token
        StringDictionary parameters2 = new StringDictionary();
        parameters2.Add(OAuth2.RedirectUriKey, "urn:ietf:wg:oauth:2.0:oob");

        string uri = "https://accounts.google.com/o/oauth2/token";

        AuthorizationServerDescription server = new AuthorizationServerDescription();
        server.TokenEndpoint = new Uri(uri);
        server.ProtocolVersion = ProtocolVersion.V20;

        consumer = new UserAgentClient(server, clientID, clientSecret);

        consumer.ClientCredentialApplicator = ClientCredentialApplicator.PostParameter(clientSecret);

        IAuthorizationState authorizationState = new AuthorizationState(null);

        if (parameters2.ContainsKey(OAuth2.RedirectUriKey))
        {
            authorizationState.Callback = new Uri(parameters2[OAuth2.RedirectUriKey]);
        }

        // Build a generic URL containing the auth code.
        // This is done here as we cannot modify the DotNetOpenAuth library 
        // and the underlying method only allows parsing an URL as a method 
        // of retrieving the AuthorizationState.
        string url = "http://example.com/?code=" + key;

        try
        {
            grantedAccess = consumer.ProcessUserAuthorization(new Uri(url), authorizationState);
        }
        catch (DotNetOpenAuth.Messaging.ProtocolException e)
        {
            Console.WriteLine(e.Message);
            return null;
        }

        return grantedAccess.AccessToken;
    }

    static void Main(string[] args)
    {
        string clientID = "somewhat like 628470012345.apps.googleusercontent.com";
        string clientSecret = "somewhat like 8IbRSofadFQ7ThjClxp8GBa2";
        string userEmail = "john.doe@gmail.com";

        OAuth2 myOAuth2 = new OAuth2(clientID, clientSecret);

        StringDictionary parameters1 = new StringDictionary();
        parameters1.Add(OAuth2.Scope, "https://mail.google.com/");
        parameters1.Add(OAuth2.RedirectUriKey, "urn:ietf:wg:oauth:2.0:oob");
        parameters1.Add(OAuth2.ResponseTypeKey, "code");

        // First: Redirect to Authorization and Fire up the browser
        System.Diagnostics.Process.Start(
            myOAuth2.AuthorizeToken("https://accounts.google.com/o/oauth2/auth", parameters1));

        Console.Write("Please enter the Authorization key from Google: ");
        string key = Console.ReadLine().Trim();

        // Second: Fetch Access Token
        string accessToken = GetAccessToken(clientID, clientSecret, key);
        if (accessToken == null)
        {
            return;
        }

        // Get XOAuth key for IMAP.
        string imapXOAuthKey = myOAuth2.GetXOAuthKey(userEmail, accessToken);

        Imap imp = new Imap();

        // In the log, you can find the actual search queries sent to the server.
        imp.Log.Filename = "C:\\Temp\\log.txt";
        imp.Log.Enabled = true;
        imp.Log.Clear();

        imp.Connect("imap.gmail.com", 993);
        imp.Login(null, imapXOAuthKey, AuthenticationMethods.SaslOAuth2, AuthenticationOptions.None, null);
        imp.SelectFolder("INBOX");

        Console.WriteLine(imp.MessageCount.ToString() + " message(s) in INBOX");

        imp.Disconnect();
    }
}

Imports System.Collections.Specialized
Imports MailBee
Imports MailBee.ImapMail
Imports DotNetOpenAuth.OAuth2

Class Sample
    Shared Function GetAccessToken(clientID As String, clientSecret As String, key As String) As String
        Dim consumer As UserAgentClient
        Dim grantedAccess As IAuthorizationState

        ' Second: Fetch Access Token
        Dim parameters2 As New StringDictionary()
        parameters2.Add(OAuth2.RedirectUriKey, "urn:ietf:wg:oauth:2.0:oob")

        Dim uri As String = "https://accounts.google.com/o/oauth2/token"

        Dim server As New AuthorizationServerDescription
        With server
            .TokenEndpoint = New Uri(uri)
            .ProtocolVersion = ProtocolVersion.V20
        End With

        consumer = New UserAgentClient(server, clientID, clientSecret)

        consumer.ClientCredentialApplicator = ClientCredentialApplicator.PostParameter(clientSecret)

        Dim authorizationState As IAuthorizationState = New AuthorizationState(Nothing)

        If parameters2.ContainsKey(OAuth2.RedirectUriKey) Then
            authorizationState.Callback = New Uri(parameters2(OAuth2.RedirectUriKey))
        End If

        ' Build a generic URL containing the auth code.
        ' This is done here as we cannot modify the DotNetOpenAuth library 
        ' and the underlying method only allows parsing an URL as a method 
        ' of retrieving the AuthorizationState.
        Dim url As String = "http://example.com/?code=" & key

        Try
            grantedAccess = consumer.ProcessUserAuthorization(New Uri(url), authorizationState)
        Catch e As DotNetOpenAuth.Messaging.ProtocolException
            Console.WriteLine(e.Message)
            Return Nothing
        End Try

        Return grantedAccess.AccessToken
    End Function

    Shared Sub Main()
        Dim clientID As String = "somewhat like 628470012345.apps.googleusercontent.com"
        Dim clientSecret As String = "somewhat like 8IbRSofadFQ7ThjClxp8GBa2"
        Dim userEmail As String = "john.doe@gmail.com"

        Dim myOAuth2 As New OAuth2(clientID, clientSecret)

        Dim parameters1 As New StringDictionary()
        parameters1.Add(OAuth2.Scope, "https://mail.google.com/")
        parameters1.Add(OAuth2.RedirectUriKey, "urn:ietf:wg:oauth:2.0:oob")
        parameters1.Add(OAuth2.ResponseTypeKey, "code")

        ' First: Redirect to Authorization and Fire up the browser
        System.Diagnostics.Process.Start(myOAuth2.AuthorizeToken("https://accounts.google.com/o/oauth2/auth", parameters1))

        Console.Write("Please enter the Authorization key from Google: ")
        Dim key As String = Console.ReadLine().Trim()

        ' Second: Fetch Access Token
        Dim accessToken As String = GetAccessToken(clientID, clientSecret, key)
        If accessToken Is Nothing Then
            Return
        End If

        ' Get XOAuth key for IMAP.
        Dim imapXOAuthKey As String = myOAuth2.GetXOAuthKey(userEmail, accessToken)

        Dim imp As New Imap()

        ' In the log, you can find the actual search queries sent to the server.
        imp.Log.Filename = "C:\Temp\log.txt"
        imp.Log.Enabled = True
        imp.Log.Clear()

        imp.Connect("imap.gmail.com", 993)
        imp.Login(Nothing, imapXOAuthKey, AuthenticationMethods.SaslOAuth2, AuthenticationOptions.None, Nothing)
        imp.SelectFolder("INBOX")

        Console.WriteLine(imp.MessageCount.ToString() & " message(s) in INBOX")

        imp.Disconnect()
    End Sub
End Class