我在使用IMAP阅读电子邮件时获取原始文本

Question

I have taken some code from MSDN to read emails using IMAP Client. I have changed little bit code so i can only read unseen email. I am writing all response in Richtextbox.

The problems is format of Body text of Email is unreadable while all other text is fine.

    void ReadEmail()
    {
        try
        {

            // there should be no gap between the imap command and the \r\n       
            // ssl.read() -- while ssl.readbyte!= eof does not work because there is no eof from server 
            // cannot check for \r\n because in case of larger response from server ex:read email message 
            // there are lot of lines so \r \n appears at the end of each line 
            //ssl.timeout sets the underlying tcp connections timeout if the read or write 
            //time out exceeds then the undelying connection is closed 
            tcpc = new System.Net.Sockets.TcpClient("imap.gmail.com", 993);

            ssl = new System.Net.Security.SslStream(tcpc.GetStream());
            ssl.AuthenticateAsClient("imap.gmail.com");
            receiveResponse("");


            username = "charlie@gmail.com";
            password = "********";

            receiveResponse("$ LOGIN " + username + " " + password + "  \r\n");

            receiveResponse("$ LIST " + "\"\"" + " \"*\"" + "\r\n");

            receiveResponse("$ SELECT INBOX\r\n");
            receiveResponse("$ UID SEARCH UNSEEN\r\n");
           MatchCollection collection= Regex.Matches(Result,@" (\d{1,4})");
           foreach (Match m in collection)
           { 
           UNREAD_UID.Add(int.Parse(m.Groups[1].Value));
           }
            foreach (int x in UNREAD_UID)
            {

                     receiveResponse("$ FETCH " +x + " body[header]\r\n");
                    richTextBox1.Text += Environment.NewLine+"-----------------------------------------------------------------------------------------------------------------------"+Environment.NewLine;
                    receiveResponse("$ FETCH " +x + " body[text]\r\n");
                    richTextBox1.Text += Environment.NewLine + "@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@2" + Environment.NewLine;
                    richTextBox1.Update();
            }


            //receiveResponse("$ STATUS INBOX (MESSAGES)\r\n");


          //  int number = 1;



            receiveResponse("$ LOGOUT\r\n");
        }
        catch (Exception ex)
        {
            Console.WriteLine("error: " + ex.Message);
        }
        finally
        {
            if (sw != null)
            {
                sw.Close();
                sw.Dispose();
            }
            if (ssl != null)
            {
                ssl.Close();
                ssl.Dispose();
            }
            if (tcpc != null)
            {
                tcpc.Close();
            }
        }
     }

---

   void receiveResponse(string command)
    {
        try
        {
            if (command != "")
            {
                if (tcpc.Connected)
                {
                    dummy = Encoding.ASCII.GetBytes(command);
                    ssl.Write(dummy, 0, dummy.Length);
                }
                else
                {
                    throw new ApplicationException("TCP CONNECTION DISCONNECTED");
                }
            }
            ssl.Flush();
            buffer = new byte[5120];
            bytes = ssl.Read(buffer, 0, 5120);
            sb.Append(Encoding.ASCII.GetString(buffer));
            Result = sb.ToString();
            richTextBox1.Text += Environment.NewLine + Environment.NewLine + Environment.NewLine + Environment.NewLine + sb.ToString();
            sb = new StringBuilder();

        }
        catch (Exception ex)
        {
            throw new ApplicationException(ex.Message);
        }
    } 

Here is Sample of what i am getting

108 FETCH (BODY[TEXT] {25656} DQoNCg0KDQo8IURPQ1RZUEUgaHRtbD4NCjxodG1sPg0KPGhlYWQ+DQo8dGl0bGU+TWlj cm9zb2Z0IHR1cm5zIChhbG1vc3QpIGFueSBjYW1lcmEgaW50byBhIEtpbmVjdDwvdGl0 bGU+DQo8bWV0YSBodHRwLWVxdWl2PSJDb250ZW50LVR5cGUiIGNvbnRlbnQ9InRleHQv aHRtbDsgY2hhcnNldD1VVEYtOCI+DQo8bWV0YSBuYW1lPSJ2aWV3cG9ydCIgY29udGVu dD0id2lkdGg9ZGV2aWNlLXdpZHRoIj4NCjwhLS0gRWZmaW5nIFdpbmRvd3MgOCBNYWls IGNsaWVudC4gQWRkIC13ZWJraXQtbWluLWRldmljZS1waXhlbC1yYXRpbzogMSB0byBz Y2FyZSBpdCBhd2F5IGZyb20gdGhpcyBiaXQuIC0tPg0KPHN0eWxlIHR5cGU9InRleHQv Y3NzIj4NCkBtZWRpYSBzY3JlZW4gYW5kIChtYXgtZGV2aWNlLXdpZHRoOiA1MDBweCkg YW5kICgtd2Via2l0LW1pbi1kZXZpY2UtcGl4ZWwtcmF0aW86IDEpIHsNCgkuYm9keS1j b250YWluZXIgeyB3aWR0aDoxMDAlICFpbXBvcnRhbnQ7IH0NCgkuYmFubmVyICAgICAg ICAgeyBkaXNwbGF5OiBub25lICFpbXBvcnRhbnQ7IH0NCgkubW9iaWxlLWJhbm5lciAg eyBkaXNwbGF5OiBibG9jayAhaW1wb3J0YW50OyB3aWR0aDozNDBweCAhaW1wb3J0YW50 OyBiYWNrZ3JvdW5kOiB1cmwoaHR0cDovL3d3dy5jb2RlcHJvamVjdC5jb20vc2NyaXB0 L21haWxvdXRzL3RlbXBsYXRlcy9uZXdzbGV0dGVyLWluc2lkZXIucG5nKSBuby1yZXBl YXQg dG9wIGxlZ

Kindly help me.

Answer 1

You need to examine the Content-Transfer-Encoding header to undo Transfer encoding (in this case, that's Base64. Other alternatives are 7-bit or Quoted Printable). Or, better, download the entire message (Body[]) and apply a MIME parser/decoder to it to get an object representation of the headers, body, and attachments.

Answer 2

Max's answer above is correct, but I'm going to illustrate how to implement his suggestion using my MailKit library:

using (var client = new ImapClient ()) {
    client.Connect ("imap.gmail.com", 993, true);

    // since we're not using an OAuth2 token, remove it from the set
    // of possible authentication mechanisms to try:
    client.AuthenticationMechanisms.Remove ("XOAUTH2");

    client.Authenticate ("charlie@gmail.com", "*****");

    // SELECT the INBOX folder
    client.Inbox.Open (FolderAccess.ReadWrite);

    foreach (var uid in client.Inbox.Search (SearchQuery.NotSeen)) {
        var message = client.Inbox.GetMessage (uid);

        // at this point, 'message' is a MIME DOM that you can walk
        // over to get the particular MIME-part that you want. For
        // example, we could get a body part with a filename of
        // "test.txt" using LINQ like this:
        var attachment = message.BodyParts.OfType<MimePart> ()
            .FirstOrDefault (x => x.FileName == "test.txt");

        // decode the content to a MemoryStream:
        using (var memory = new MemoryStream ()) {
            attachment.ContentObject.DecodeTo (memory);
        }

        // since the attachment is probably a TextPart
        // (based on the file extension above), we can actually
        // use a simpler approach:
        var textPart = attachment as TextPart;
        if (textPart != null) {
            // decode the content and convert into a 'string'
            var text = textPart.Text;
        }
    }

    client.Disconnect (true);
}