Might be an Encoding Problem

[jeromeentredicho]

This is a code that connects to gmail, passes my username and password then retrieve the response. It seems to be working fine but the problem is the response. I was instructed that the response should be like "+OK" or "-Err", instead it shows weird characters. A fellow told me that there must be a problem with the encoding... So here it is... please help me...

This is my code:

Dim _server As TcpClient
Dim _netstream As NetworkStream
Dim _stmreader As StreamReader
Dim _senddata() As Byte
Dim _ssl As Net.Security.SslStream
Dim _user, _password As String

Try
_server = New TcpClient("pop.gmail.com", 995)
_netstream = _server.GetStream
_ssl = New Net.Security.SslStream(_server.GetStream())
DirectCast(_ssl, Net.Security.SslStream).AuthenticateAsClient("pop.gmail.com")
_stmreader = New StreamReader(_server.GetStream)
Catch _ex As Exception
MsgBox(_ex.Message)
Exit Sub
End Try

_user = "username@gmail.com"
_password = "password"

_senddata = System.Text.Encoding.ASCII.GetBytes(("USER" + _user.Trim + vbCrLf).ToCharArray())
_netstream.Write(_senddata, 0, _senddata.Length)
_senddata = System.Text.Encoding.ASCII.GetBytes(("PASS" + _password.Trim + vbCrLf).ToCharArray())
_netstream.Write(_senddata, 0, _senddata.Length)
_senddata = System.Text.Encoding.ASCII.GetBytes(("STAT" + vbCrLf).ToCharArray())
_netstream.Write(_senddata, 0, _senddata.Length)
MsgBox(_stmreader.ReadLine)


I'm using Visual Studio 2008 on Windows 7 Ultimate...

[Bill Crawley]

_senddata = System.Text.Encoding.ASCII.GetBytes(("STAT" + vbCrLf).ToCharArray())
_netstream.Write(_senddata, 0, _senddata.Length)
MsgBox(_stmreader.ReadLine)

the MsgBox here looks very suspicious. The trouble is straight after you write to the stream you are trying to read a response. This assumes that the response is instant and that the other app and comms have been quicker than Msgbox. This is unlikely to be the case. I would expect some kind of event be raised from the other app and your application lookiing out for that event. Only then can you ensure that you are receiving all data in the stream. Check out Async communication there are loads of examples out there. I suspect this is what you really need.

also anything you read, you may need to use Decode as opposed to Encode

Here is an example of mine the uses Async. I happen to be passing xml data to a service and then am waiting for a new xml document to be returned. There is no reason why you cant use this principal in your code.

On the main thread create a background worker, by doing this it opens a new thread and then waits for this thread to return. My code is in C# but you can easily convert to VB.

 worker = new BackgroundWorker();
            worker.DoWork += new DoWorkEventHandler(worker_DoWork);
            worker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(worker_RunWorkerCompleted);
            worker.RunWorkerAsync();

Now we have this established worker_RunWorkerCompleted is the event that receives the returning data, so this is where you would place your msgBox and do anything with the incoming stream.

void worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            callback.OnRatabaseCallback(xmlData);
        }

protected void worker_DoWork(object sender, DoWorkEventArgs e)
        {
            
            try
            {......

The worker_DoWork is where you make the call to the other application.

All of this is in a WCF Service, but it doesn't have to be