Hi guys,

I am working on retrieving mails from a pop3 server (currently gmail). The code is as below. It can susseccfully connect to the server and authenticate. It fetches the message details by providing it the message number, though i am not sure how does it assign message number. Now the main problem is that i first want to get the header information like message sender, date, subject, attachment info. This information will be shown as a grid to the user and then the user will select a message which will then be retrieved from the server. How do i get the message header information? Please help.

This is only the relevant code, the entire form-specifc code can be easily understood and is not necessary to put here.

Here POPServ.Text could be like pop.gmail.com, User.Text=a valid email account in gamil, Passw.Text = user password



using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Net;
using System.Net.Sockets;
using System.Net.Security;
using System.Security.Cryptography.X509Certificates;
using System.IO;
using System.Text;

namespace POPapp
{
    /// <summary>
    /// Summary description for Form1.
    /// </summary>
    public class POPForm : System.Windows.Forms.Form
    {

        public static bool ValidateServerCertificate(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
        {
            if (sslPolicyErrors == SslPolicyErrors.None)
                return true;
            else
                return false;
        }


        public static string ReadMessage(SslStream sslStream1, bool MultilineResponse)
        {
            byte[] buffer = new byte[1024];
            int bytes = -1;
            StringBuilder messageData = new StringBuilder();
            Decoder decoder = Encoding.UTF8.GetDecoder();
            char[] chars;

            while (true)
            {
                bytes = sslStream1.Read(buffer, 0, buffer.Length);
                if (bytes <= 0)
                    break;
                chars = new char[decoder.GetCharCount(buffer, 0, bytes)];
                decoder.GetChars(buffer, 0, bytes, chars, 0);
                messageData.Append(chars);
                if (!MultilineResponse)
                    break;
                else if (messageData.ToString().EndsWith("\r\n.\r\n"))
                    break;
            }
            return messageData.ToString();
        }



        private void ConnectBtn_Click(object sender, System.EventArgs e)
        {
            // change cursor into wait cursor
            Cursor cr = Cursor.Current;
            Cursor.Current = Cursors.WaitCursor;

            // create server POP3 with port 110
            //Server = new TcpClient(POPServ.Text,110);
            Server = new TcpClient(POPServ.Text, 995);
            Status.Items.Clear();

            try
            {
                /////////////////////////////////////////////////////////////////////////
                sslStream = new SslStream(Server.GetStream(), false, new RemoteCertificateValidationCallback(ValidateServer Certificate), null);
                sslStream.AuthenticateAsClient(POPServ.Text);
                string messageData = ReadMessage(sslStream, false);
                Status.Items.Add(messageData);

                Data = "USER " + User.Text + CRLF;
                szData = System.Text.Encoding.ASCII.GetBytes(Data.ToCharArr ay());
                sslStream.Write(szData, 0, szData.Length);
                sslStream.Flush();
                messageData = ReadMessage(sslStream, false);
                Status.Items.Add(messageData);

                Data = "PASS " + Passw.Text + CRLF;
                szData = System.Text.Encoding.ASCII.GetBytes(Data.ToCharArr ay());
                sslStream.Write(szData, 0, szData.Length);
                sslStream.Flush();
                messageData = ReadMessage(sslStream, false);
                Status.Items.Add(messageData);

                Data = "STAT" + CRLF;
                szData = System.Text.Encoding.ASCII.GetBytes(Data.ToCharArr ay());
                sslStream.Write(szData, 0, szData.Length);
                sslStream.Flush();
                messageData = ReadMessage(sslStream, false);
                Status.Items.Add(messageData);

                Data = "LIST" + CRLF;
                szData = System.Text.Encoding.ASCII.GetBytes(Data.ToCharArr ay());
                sslStream.Write(szData, 0, szData.Length);
                sslStream.Flush();
                messageData = ReadMessage(sslStream, true);
                Status.Items.Add(messageData);

                /////////////////////////////////////////////////////////////////////////

                // change enabled - disabled button
                ConnectBtn.Enabled = false;
                DisconnectBtn.Enabled = true;
                RetrieveBtn.Enabled = true;

                // back to normal cursor
                Cursor.Current = cr;

            }
            catch (InvalidOperationException err)
            {
                Status.Items.Add("Error: " + err.ToString());
            }
        }


        private void RetrieveBtn_Click(object sender, System.EventArgs e)
        {
            // change cursor into wait cursor
            Cursor cr = Cursor.Current;
            Cursor.Current = Cursors.WaitCursor;
            string szTemp;
            Message.Clear();
            try
            {
                // retrieve mail with number mail parameter
                Data = "RETR " + Number.Text + CRLF;
                szData = System.Text.Encoding.ASCII.GetBytes(Data.ToCharArr ay());


                sslStream.Write(szData, 0, szData.Length);
                sslStream.Flush();
                string messageData = ReadMessage(sslStream, true);
                Message.Text = messageData;


                // back to normal cursor
                Cursor.Current = cr;

            }
            catch (InvalidOperationException err)
            {
                Status.Items.Add("Error: " + err.ToString());
            }

        }
    }
}


BaburMan

__________________
BaburMan

The "TOP" command retrieves the headers and an optional number of lines from the message. This is an optional POP3 command, but is supported by most modern mail servers so shouldn't be a problem.

/- Sam Judson : Wrox Technical Editor -/

Sam! Thank you for the reply. But here i encounter another problem. Against one of the client's test account on gmail i get the following response when i use STAT command:


+OK 0 0\r\n


Which means there are 0 messages in his inbox whereas i can see there are 92 messages when i look into them directly through gmail. There are many unread records as well. What's wrong with the code then? Its really annoying to me. Please help.



BaburMan

Have you popped messages from Gmail before? I believe by default Gmail only exposes messages through pop since you enabled pop, although you can change that in the settings.....

Imar

---------------------------------------
Imar Spaanjaars
http://Imar.Spaanjaars.Com
Everyone is unique, except for me.
Author of Beginning ASP.NET 3.5 : in C# and VB, ASP.NET 2.0 Instant Results and Dreamweaver MX 2004
Want to be my colleague? Then check out this post.

Yes i popped messages using my own gmail account. Though there are a couple of other issues but definitely i get the results of STAT, LIST and RETR commands successfully.



BaburMan

Ok, now successfully getting mails. Don't know why it wasn't working before. Anyways thank you guys for your suggestions. :)

BaburMan

The code has been working successfully. Now the client asked to write code to delete some selected messages. I used dele command. The code follows:

Data = "DELE 2 \r\n";
szData = System.Text.Encoding.ASCII.GetBytes(Data.ToCharArr ay());
sslStream.Write(szData, 0, szData.Length);
sslStream.Flush();
messageData = ReadMessage(sslStream, true);


The problem is that the server response is too slow for dele. It takes about 10 minutes to come back and respond for success. Secondly the dele command requires the quit command at the end so that all updation can be committed to the server:

Data = "QUIT \r\n";
szData = System.Text.Encoding.ASCII.GetBytes(Data.ToCharArr ay());
sslStream.Write(szData, 0, szData.Length);
sslStream.Flush();
messageData = ReadMessage(sslStream, true);


Here the last line which reads the response from the server for quit command causes an exception that says the software that is running in the host machine closed the connection. When i comment out dele command the quit command successfuly ends the session.

__________________
BaburMan

hi guys..

i m using the above code, but its not worked for me. When i m giving username then in the function "ReadMessage" - the variable bytes gets 0 so because of this it come out from While loop and same happens with the password.
i want to access my gmail acount through progrmming (vb.net/C#.net)
but i am facing problem....
plz help me ...

Thanks and Regards,
Gauri

Gauri!

You have to give proper pop server credentials. Like for gmail i have set the server as "pop.gmail.com" and the port as 995. For gmail, you also need to allow accessing pop mails right from your gmail account. There's a link that says "Settings" somewhere on the top which you have to explore a bit. For other servers i am not sure. Are you able to connect to the pop server? Consider the following lines which connect to the server:

sslStream = new SslStream(Server.GetStream(), false, new RemoteCertificateValidationCallback(ValidateServer Certificate), null);
sslStream.AuthenticateAsClient(POPServ.Text);
string messageData = ReadMessage(sslStream, false);

Here what i get as a response in messageData is "+OK Gpop ready for requests from ...". Which means the pop server connected successfully. If you get a message like this then you are ok and now you should enter correct email and password in the subsequent calls. Let me know if still not working.

__________________
BaburMan

Finally found the reason. It was a little mistake. The lines

messageData = ReadMessage(sslStream, true);

for DELE and QUIT should be slightly modified to

messageData = ReadMessage(sslStream, false);

and here we go. Everything works fine . In fact the second parameter of ReadMessage() should be set to true only if its command expects multiple- line response from the server.

__________________
BaburMan