Mail library using sockets, in C#

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• Download demo project - 8.63 Kb

1. Introduction

This mail library is an extension of SocketHelper which is described in my previous article.

No CDO needed and no System.Web.Mail which is a package to CDO needed.

Now, let's see what is inside.

2. Classes

1. MailMessage
2. SmtpServer

MailMessage is used for storing mail messages (currently doesn't support attachments).

SmtpServer is a class to communicate with SMTP servers, inside which there is a SocketHelper (with some updates, download source code for detail).

3. Code Detail

The class MailMessage:

    public class MailMessage
    {
        public enum BodyFormat
        {
            HTML,TEXT
        }

        private string sFrom;
        private string sTo;
        private string sCc;
        private string sSubject;
        private BodyFormat bfFormat=BodyFormat.TEXT;
        private string sBody;
        private string sFromName;
        private string sToName;

        public string Cc
        {
            get
            {
                return sCc;
            }
            set
            {
                sCc=value;
            }
        }

        public string FromName
        {
            get
            {
                if(sFromName==null || sFromName=="")
                    sFromName=sFrom;

                return sFromName;
            }
            set
            {
                sFromName=value;
            }
        }

        public string ToName
        {
            get
            {
                if(sToName==null || sToName=="")
                    sToName=sTo;

                return sToName;
            }
            set
            {
                sToName=value;
            }
        }

        public string From
        {
            get
            {
                return sFrom;
            }
            set
            {
                sFrom=value;
            }
        }

        public string To
        {
            get
            {
                return sTo;
            }
            set
            {
                sTo=value;
            }
        }

        public string Subject
        {
            get
            {
                return sSubject;
            }
            set
            {
                sSubject=value;
            }
        }

        public string Body
        {
            get
            {
                return sBody;
            }
            set
            {
                sBody=value;
            }
        }

        public BodyFormat MailFormat
        {
            get
            {
                return bfFormat;
            }
            set
            {
                bfFormat=value;
            }
        }

        public MailMessage()
        {
            //

            // TODO: Add constructor logic here

            //

        }

        public override string ToString()
        {
            StringBuilder sb=new StringBuilder();
            sb.AppendFormat("From: {0}\r\n",this.FromName);
            sb.AppendFormat("To: {0}\r\n",this.ToName);
            if(this.Cc!=null && this.Cc!="")
            {
                sb.AppendFormat("Cc: {0}\r\n",this.Cc.Replace(";",","));
            }
            sb.AppendFormat("Date: {0}\r\n", 
              DateTime.Now.ToString("ddd, d M y H:m:s z"));
            sb.AppendFormat("Subject: {0}\r\n",this.Subject);
            sb.AppendFormat("X-Mailer: vmlinux.Net.Mail.SmtpServer\r\n");
            switch(this.MailFormat)
            {
                case BodyFormat.TEXT:
                  sb.AppendFormat("Content-type:text/plain;Charset=GB2312\r\n");
                  break;
                case BodyFormat.HTML:
                  sb.AppendFormat("Content-type:text/html;Charset=GB2312\r\n");
                  break;
                default:
                  break;
            }
            sb.AppendFormat("\r\n{0}\r\n",this.Body);
            return sb.ToString();
        }
    }

I get all the message inside mail through the method ToString().

Now, the following is class SmtpServer:

    public class SmtpServer
    {
        private string sServer;
        private int iPort;
        private bool bAuth=false;
        private string sUser;
        private string sPass;
        private StringBuilder sbLog=null;
        private bool bLog=true;
        private SocketHelper helper=null;
        private TalkState state=TalkState.WaitInit;

        public enum TalkState
        {
            WaitInit,Initialized,SignedIn,LoginFailed,Ended
        }

        protected SocketHelper Helper
        {
            get
            {
                if(helper==null)
                    helper=new SocketHelper(this.Server,this.Port);

                return helper;
            }
        }

        public bool LogEvent
        {
            get
            {
                return bLog;
            }
            set
            {
                bLog=value;
            }
        }

        public string LogMessage
        {
            get
            {
                if(this.LogEvent)
                    return sbLog.ToString();
                else
                    return "";
            }
        }

        public string Server
        {
            get
            {
                return sServer;
            }
            set
            {
                sServer=value;
            }
        }

        public int Port
        {
            get
            {
                return iPort;
            }
            set
            {
                iPort=value;
            }
        }

        public bool RequireAuthorization
        {
            get
            {
                return bAuth;
            }
            set
            {
                bAuth=value;
            }
        }

        public string AuthUser
        {
            get
            {
                return sUser;
            }
            set
            {
                sUser=value;
            }
        }

        public string AuthPass
        {
            get
            {
                return sPass;
            }
            set
            {
                sPass=value;
            }
        }

        public SmtpServer()
        {
            //

            // TODO: Add constructor logic here

            //

        }

        public void Init()
        {
            Log(helper.GetFullResponse());
            Helper.SendCommand("EHLO "+this.Server);
            Log(Helper.GetFullResponse());
            state=TalkState.Initialized;
        }

        public bool Login()
        {
            if(this.RequireAuthorization)
            {
                Helper.SendCommand("AUTH LOGIN");
                Log(Helper.GetFullResponse());
                Helper.SendCommand(
                    Convert.ToBase64String(
                    Encoding.Default.GetBytes(this.AuthUser)));
                Log(Helper.GetFullResponse());
                Helper.SendCommand(
                    Convert.ToBase64String(
                    Encoding.Default.GetBytes(this.AuthPass)));
                Log(Helper.GetFullResponse());

                if(Helper.GetResponseState()==235)
                {
                    state=TalkState.SignedIn;
                    return true;
                }
                else
                {
                    state=TalkState.LoginFailed;
                    return false;
                }
//                return (Helper.GetResponseState()==235);

            }
            else
            {
                state=TalkState.SignedIn;
                return true;
            }
        }

        public void SendKeep(MailMessage msg)
        {
            if((state==TalkState.Initialized && 
               !this.RequireAuthorization) || state==TalkState.SignedIn)
            {
                Helper.SendCommand("MAIL From:"+msg.From);
                Log(Helper.GetFullResponse());
                Helper.SendCommand("RCPT To:"+msg.To);
                Log(Helper.GetFullResponse());
                Helper.SendCommand("DATA");
                Log(Helper.GetFullResponse());
                Helper.SendData(Encoding.Default.GetBytes(msg.ToString()));
                Helper.SendCommand(".");
                Log(Helper.GetFullResponse());
            }
        }

        public void Quit()
        {
            Helper.SendCommand("QUIT");
            Helper.Close();
            state=TalkState.Ended;
        }

        public bool Send(MailMessage msg)
        {
            if(state==TalkState.Ended)
                return false;

            Log(Helper.GetFullResponse());
            Helper.SendCommand("EHLO "+this.Server);
            Log(Helper.GetFullResponse());
            if(this.RequireAuthorization)
            {
                Helper.SendCommand("AUTH LOGIN");
                Log(Helper.GetFullResponse());
                Helper.SendCommand(
                    Convert.ToBase64String(
                    Encoding.Default.GetBytes(this.AuthUser)));
                Log(Helper.GetFullResponse());
                Helper.SendCommand(
                    Convert.ToBase64String(
                    Encoding.Default.GetBytes(this.AuthPass)));
                Log(Helper.GetFullResponse());
                if(Helper.GetResponseState()!=235)
                {
                    Helper.SendCommand("QUIT");
                    Helper.Close();
                    state=TalkState.Ended;
                    return false;
                }
            }
            Helper.SendCommand("MAIL From:"+msg.From);
            Log(Helper.GetFullResponse());
            Helper.SendCommand("RCPT To:"+msg.To);
            Log(Helper.GetFullResponse());
            Helper.SendCommand("DATA");
            Log(Helper.GetFullResponse());
            Helper.SendData(Encoding.Default.GetBytes(msg.ToString()));
            Helper.SendCommand(".");
            Log(Helper.GetFullResponse());
            Helper.SendCommand("QUIT");
            Helper.Close();
            state=TalkState.Ended;
            return true;
        }

        private void Log(string msg)
        {
            if(this.LogEvent)
            {
                if(sbLog==null)
                    sbLog=new StringBuilder();

                sbLog.AppendFormat("{0}\r\n",msg);
            }
        }
    }

You can send multiple emails in one connection or simply send one.

To send multiple emails, follow this command sequence:

1. Init --- to receive server response and say hello.
2. Login --- if the server requires user login.
3. SendKeep --- send mail and keep connection.
4. ... --- more mail through SendKeep.
5. Quit --- say good bye to server.

If you are sending only one mail in one connection, simply call Send.

So that's it.

4. TODO

1. error handling
2. attachments