A POP3 e-mail checker
/*
C# Network Programming
by Richard Blum
Publisher: Sybex
ISBN: 0782141765
*/
using System;
using System.Drawing;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using System.Windows.Forms;
public class PopCheck : Form
{
private TextBox hostname;
private TextBox username;
private TextBox password;
private TextBox status;
private ListBox messages;
private TcpClient mailclient;
private NetworkStream ns;
private StreamReader sr;
private StreamWriter sw;
public PopCheck()
{
Text = "popcheck - A POP3 e-mail checker";
Size = new Size(400, 380);
Label label1 = new Label();
label1.Parent = this;
label1.Text = "Hostname:";
label1.AutoSize = true;
label1.Location = new Point(10, 33);
hostname = new TextBox();
hostname.Parent = this;
hostname.Size = new Size(200, 2 * Font.Height);
hostname.Location = new Point(75, 30);
Label label2 = new Label();
label2.Parent = this;
label2.Text = "User name:";
label2.AutoSize = true;
label2.Location = new Point(10, 53);
username = new TextBox();
username.Parent = this;
username.Size = new Size(200, 2 * Font.Height);
username.Location = new Point(75, 50);
Label label3 = new Label();
label3.Parent = this;
label3.Text = "Password:";
label3.AutoSize = true;
label3.Location = new Point(10, 73);
password = new TextBox();
password.Parent = this;
password.PasswordChar = '*';
password.Size = new Size(200, 2 * Font.Height);
password.Location = new Point(75, 70);
Label label4 = new Label();
label4.Parent = this;
label4.Text = "Status:";
label4.AutoSize = true;
label4.Location = new Point(10, 325);
status = new TextBox();
status.Parent = this;
status.Text = "Not connected";
status.Size = new Size(200, 2 * Font.Height);
status.Location = new Point(50, 322);
messages = new ListBox();
messages.Parent = this;
messages.Location = new Point(10, 108);
messages.Size = new Size(360, 16 * Font.Height);
messages.DoubleClick += new EventHandler(getmessagesDoubleClick);
Button login = new Button();
login.Parent = this;
login.Text = "Login";
login.Location = new Point(295, 32);
login.Size = new Size(5 * Font.Height, 2 * Font.Height);
login.Click += new EventHandler(ButtonloginOnClick);
Button close = new Button();
close.Parent = this;
close.Text = "Close";
close.Location = new Point(295, 62);
close.Size = new Size(5 * Font.Height, 2 * Font.Height);
close.Click += new EventHandler(ButtoncloseOnClick);
}
void ButtonloginOnClick(object obj, EventArgs ea)
{
status.Text = "Checking for messages...";
Thread startlogin = new Thread(new ThreadStart(loginandretr));
startlogin.IsBackground = true;
startlogin.Start();
}
void ButtoncloseOnClick(object obj, EventArgs ea)
{
if (ns != null)
{
sw.Close();
sr.Close();
ns.Close();
mailclient.Close();
}
Close();
}
void loginandretr()
{
string response;
string from = null;
string subject = null;
int totmessages;
try
{
mailclient = new TcpClient(hostname.Text, 110);
} catch (SocketException)
{
status.Text = "Unable to connect to server";
return;
}
ns = mailclient.GetStream();
sr = new StreamReader(ns);
sw = new StreamWriter(ns);
response = sr.ReadLine(); //Get opening POP3 banner
sw.WriteLine("User " + username.Text); //Send username
sw.Flush();
response = sr.ReadLine();
if (response.Substring(0,4) == "-ERR")
{
status.Text = "Unable to log into server";
return;
}
sw.WriteLine("Pass " + password.Text); //Send password
sw.Flush();
try
{
response = sr.ReadLine();
} catch (IOException)
{
status.Text = "Unable to log into server";
return;
}
if (response.Substring(0,3) == "-ER")
{
status.Text = "Unable to log into server";
return;
}
sw.WriteLine("stat"); //Send stat command to get number of messages
sw.Flush();
response = sr.ReadLine();
string[] nummess = response.Split(' ');
totmessages = Convert.ToInt16(nummess[1]);
if (totmessages > 0)
{
status.Text = "you have " + totmessages + " messages";
} else
{
status.Text = "You have no messages" ;
}
for (int i = 1; i <= totmessages; i++)
{
sw.WriteLine("top " + i + " 0"); //read header of each message
sw.Flush();
response = sr.ReadLine();
while (true)
{
response = sr.ReadLine();
if (response == ".")
break;
if (response.Length > 4)
{
if (response.Substring(0, 5) == "From:")
from = response;
if (response.Substring(0, 8) == "Subject:")
subject = response;
}
}
messages.Items.Add(i + " " + from + " " + subject);
}
}
void getmessagesDoubleClick(object obj, EventArgs ea)
{
string text = (string)messages.SelectedItem;
string[] textarray = text.Split(' ');
ShowMessage sm = new ShowMessage(ns, textarray[0]);
sm.ShowDialog();
}
public static void Main()
{
Application.Run(new PopCheck());
}
}
class ShowMessage : Form
{
public ShowMessage(NetworkStream ns, string messnumber)
{
StreamReader sr = new StreamReader(ns);
StreamWriter sw = new StreamWriter(ns);
string response;
Text = "Message " + messnumber;
Size = new Size(400, 380);
ShowInTaskbar = false;
TextBox display = new TextBox();
display.Parent = this;
display.Multiline = true;
display.Dock = DockStyle.Fill;
display.ScrollBars = ScrollBars.Both;
sw.WriteLine("retr " + messnumber); //Retrieve entire message
sw.Flush();
response = sr.ReadLine();
while (true)
{
response = sr.ReadLine();
if (response == ".")
break;
display.Text += response + "\r\n";
}
}
}
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