/pop3/Pop3Client.cs

using System;

using System.Collections;

using System.IO;

using System.Net;

using System.Net.Sockets;

using System.Threading;

using System.Text;

using System.Text.RegularExpressions;

using System.Diagnostics;



namespace Pop3

{

	public class Pop3Client

	{

		private Pop3Credential m_credential;



		private const int m_pop3port = 110;

		private const int MAX_BUFFER_READ_SIZE = 256;

		

		private long m_inboxPosition = 0;

		private long m_directPosition = -1;



		private Socket m_socket = null;

 

		private Pop3Message m_pop3Message = null;



		public Pop3Credential UserDetails

		{

			set { m_credential = value; }

			get { return m_credential; }

		}



        public long InboxPosition

        {

            get 

            {

                return this.m_pop3Message.InboxPosition;

            }

        }



        public string ContentType

        {

            get { return m_pop3Message.ContentType; }

        }





		public string From

		{

			get { return m_pop3Message.From; }

		}



		public string To

		{

			get { return m_pop3Message.To; }

		}



        public DateTime Date

        {

            get { return m_pop3Message.Date; }

        }



		public string Subject

		{

			get { return m_pop3Message.Subject; }

		}



		public string Body

		{

			get { return m_pop3Message.Body; }

		}



		public IEnumerator MultipartEnumerator

		{

			get { return m_pop3Message.MultipartEnumerator; }

		}



		public bool IsMultipart

		{

			get { return m_pop3Message.IsMultipart; }

		}





		public Pop3Client(string user, string pass, string server)

		{

			m_credential = new Pop3Credential(user,pass,server);

		}



		private Socket GetClientSocket()

		{

			Socket s = null;

			

			try

			{

				IPHostEntry hostEntry = null;

        

				// Get host related information.

				hostEntry = Dns.Resolve(m_credential.Server);



				// Loop through the AddressList to obtain the supported 

				// AddressFamily. This is to avoid an exception that 

				// occurs when the host IP Address is not compatible 

				// with the address family 

				// (typical in the IPv6 case).

				

				foreach(IPAddress address in hostEntry.AddressList)

				{

					IPEndPoint ipe = new IPEndPoint(address, m_pop3port);

				

					Socket tempSocket = 

						new Socket(ipe.AddressFamily, 

						SocketType.Stream, ProtocolType.Tcp);



					tempSocket.Connect(ipe);



					if(tempSocket.Connected)

					{

						// we have a connection.

						// return this socket ...

						s = tempSocket;

						break;

					}

					else

					{

						continue;

					}

				}

			}

			catch(Exception e)

			{

				throw new Pop3ConnectException(e.ToString());

			}



			// throw exception if can't connect ...

			if(s == null)

			{

				throw new Pop3ConnectException("Error : connecting to "

					+m_credential.Server);

			}

			

			return s;

		}



		//send the data to server

		private void Send(String data) 

		{

			if(m_socket == null)

			{

				throw new Pop3MessageException("Pop3 connection is closed");

			}



			try

			{

				// Convert the string data to byte data 

				// using ASCII encoding.

				

				byte[] byteData = Encoding.ASCII.GetBytes(data+"\r\n");

				

				// Begin sending the data to the remote device.

				m_socket.Send(byteData);

			}

			catch(Exception e)

			{

				throw new Pop3SendException(e.ToString());

			}

		}



		private string GetPop3String()

		{

			if(m_socket == null)

			{

				throw new 

					Pop3MessageException("Connection to POP3 server is closed");

			}



			byte[] buffer = new byte[MAX_BUFFER_READ_SIZE];

			string line = null;



			try

			{

				int byteCount = 

					m_socket.Receive(buffer,buffer.Length,0);



				line = 

					Encoding.ASCII.GetString(buffer, 0, byteCount);

			}

			catch(Exception e)

			{

				throw new Pop3ReceiveException(e.ToString());

			}



			return line;

		}



		private void LoginToInbox()

		{

			string returned;



			// send username ...

			Send("user "+m_credential.User);

		

			// get response ...

			returned = GetPop3String();



			if( !returned.Substring(0,3).Equals("+OK") )

			{

				throw new Pop3LoginException("login not excepted");

			}



			// send password ...

			Send("pass "+m_credential.Pass);



			// get response ...

			returned = GetPop3String();



			if( !returned.Substring(0,3).Equals("+OK") )

			{

				throw new 

					Pop3LoginException("login/password not accepted");

			}

		}



		public long MessageCount

		{

			get 

			{

				long count = 0;

			

				if(m_socket==null)

				{

					throw new Pop3MessageException("Pop3 server not connected");

				}



				Send("stat");



				string returned = GetPop3String();



				// if values returned ...

				if( Regex.Match(returned,

					@"^.*\+OK[ |	]+([0-9]+)[ |	]+.*$").Success )

				{

						// get number of emails ...

						count = long.Parse( Regex

						.Replace(returned.Replace("\r\n","")

						, @"^.*\+OK[ |	]+([0-9]+)[ |	]+.*$" ,"$1") );

				}



				return(count);

			}

		}





		public void CloseConnection()

		{			

			Send("quit");

            if (m_socket != null)

            {

                m_socket.Close();

                m_socket = null;

            }

			m_pop3Message = null;

		}



		public bool DeleteEmail()

		{

			bool ret = false;



			Send("dele "+m_inboxPosition);



			string returned = GetPop3String();



			if( Regex.Match(returned,

				@"^.*\+OK.*$").Success )

			{

				ret = true;

			}



			return ret;

		}



		public bool NextEmail(long directPosition)

		{

			bool ret;



			if( directPosition >= 0 )

			{

				m_directPosition = directPosition;

				ret = NextEmail();

			}

			else

			{

				throw new Pop3MessageException("Position less than zero");

			}



			return ret;

		}



		public bool NextEmail()

		{

			string returned;



			long pos;



			if(m_directPosition == -1)

			{

				if(m_inboxPosition == 0)

				{

					pos = 1;

				}

				else

				{

					pos = m_inboxPosition + 1;

				}

			}

			else

			{

				pos = m_directPosition+1;

				m_directPosition = -1;

			}



			// send username ...

			Send("list "+pos.ToString());

		

			// get response ...

			returned = GetPop3String();



			// if email does not exist at this position

			// then return false ...



			if( returned.Substring(0,4).Equals("-ERR") )

			{

				return false;

			}



			m_inboxPosition = pos;



			// strip out CRLF ...

			string[] noCr = returned.Split(new char[]{ '\r' });



			// get size ...

			string[] elements = noCr[0].Split(new char[]{ ' ' });



			long size = long.Parse(elements[2]);



			// ... else read email data

			m_pop3Message = new Pop3Message(m_inboxPosition,size,m_socket);



			return true;

		}



		public void OpenInbox()

		{

			// get a socket ...

			m_socket = GetClientSocket();



			// get initial header from POP3 server ...

			string header = GetPop3String();



			if( !header.Substring(0,3).Equals("+OK") )

			{

				throw new Exception("Invalid initial POP3 response");

			}

		

			// send login details ...

			LoginToInbox();

		}

	}

}