技术文章 > C#实现SMTP服务器

C#实现SMTP服务器

2018-04-26 17:42

文档管理软件,文档管理系统,知识管理系统,档案管理系统的技术资料:
C#实现SMTP服务器,使用TCP命令实现,功能比较完善
[code]
csharp
using System;
using System.Text;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Collections;

namespace SkyDev.Web.Mail
{
public enum MailFormat { Text, HTML };
public enum MailPriority { Low = 1, Normal = 3, High = 5 };
#region Class mailAttachments
public class MailAttachments
{
private const int MaxAttachmentNum = 10;
private IList _Attachments;
public MailAttachments()
{
_Attachments = new ArrayList();
}
public string this[int index]
{
get { return (string)_Attachments[index]; }
}
///
/// 添加邮件附件
///

/// 附件的绝对路径
public void Add(params string[] filePath)
{
if (filePath == null)
{
throw (new ArgumentNullException("非法的附件"));
}
else
{
for (int i = 0; i < filePath.Length; i++)
{
Add(filePath[i]);
}
}
}
///
/// 添加一个附件,当指定的附件不存在时,忽略该附件,不产生异常。
///

/// 附件的绝对路径
public void Add(string filePath)
{
//当附件存在时才加入,否则忽略
if (System.IO.File.Exists(filePath))
{
if (_Attachments.Count < MaxAttachmentNum)
{
_Attachments.Add(filePath);
}
}
}
public void Clear()//清除所有附件
{
_Attachments.Clear();
}
public int Count//获取附件个数
{
get { return _Attachments.Count; }
}
}
#endregion//end Class mailAttachments

#region Class MailMessage
///
/// MailMessage 表示SMTP要发送的一封邮件的消息。
///

public class MailMessage
{
private const int MaxRecipientNum = 10;
public MailMessage()
{
_Recipients = new ArrayList();//收件人列表
_Attachments = new MailAttachments();//附件
_BodyFormat = MailFormat.Text;//缺省的邮件格式为Text
_Priority = MailPriority.Normal;
_Charset = "GB2312";
}
///
/// 设定语言代码,默认设定为GB2312,如不需要可设置为""
///

public string Charset
{
get { return _Charset; }
set { _Charset = value; }
}
public string From
{
get { return _From; }
set { _From = value; }
}
public string FromName
{
get { return _FromName; }
set { _FromName = value; }
}
public string Body
{
get { return _Body; }
set { _Body = value; }
}
public string Subject
{
get { return _Subject; }
set { _Subject = value; }
}
public MailAttachments Attachments
{
get { return _Attachments; }
set { _Attachments = value; }
}
public MailPriority Priority
{
get { return _Priority; }
set { _Priority = value; }
}
public IList Recipients
{
get { return _Recipients; }
}
///
/// 增加一个收件人地址
///

/// 收件人的Email地址
public void AddRecipients(string recipient)
{
//先检查邮件地址是否符合规范
if (_Recipients.Count < MaxRecipientNum)
{
_Recipients.Add(recipient);//增加到收件人列表
}
}
public void AddRecipients(params string[] recipient)
{
if (recipient == null)
{
throw (new ArgumentException("收件人不能为空."));
}
else
{
for (int i = 0; i < recipient.Length; i++)
{
AddRecipients(recipient[i]);
}
}
}
public MailFormat BodyFormat
{
set { _BodyFormat = value; }
get { return _BodyFormat; }
}
private string _From;//发件人地址
private string _FromName;//发件人姓名
private IList _Recipients;//收件人
private MailAttachments _Attachments;//附件
private string _Body;//内容
private string _Subject;//主题
private MailFormat _BodyFormat;//邮件格式
private string _Charset = "GB2312";//字符编码格式
private MailPriority _Priority;//邮件优先级
}
#endregion

#region Class SmtpMail
public class SmtpServerHelper
{
private string CRLF = "\r\n";//回车换行
///
/// 错误消息反馈
///

private string errmsg;
///
/// TcpClient对象,用于连接服务器
///

private TcpClient tcpClient;
///
/// NetworkStream对象
///

private NetworkStream networkStream;
///
/// 服务器交互记录
///

private string logs = "";
///
/// SMTP错误代码哈希表
///

private Hashtable ErrCodeHT = new Hashtable();
///
/// SMTP正确代码哈希表
///

private Hashtable RightCodeHT = new Hashtable();
public SmtpServerHelper()
{
SMTPCodeAdd();//初始化SMTPCode
}
~SmtpServerHelper()
{
networkStream.Close();
tcpClient.Close();
}
///
/// 将字符串编码为Base64字符串
///

/// 要编码的字符串
private string Base64Encode(string str)
{
byte[] barray;
barray = Encoding.Default.GetBytes(str);
return Convert.ToBase64String(barray);
}
///
/// 将Base64字符串解码为普通字符串
///

/// 要解码的字符串
private string Base64Decode(string str)
{
byte[] barray;
barray = Convert.FromBase64String(str);
return Encoding.Default.GetString(barray);
}
///
/// 得到上传附件的文件流
///

/// 附件的绝对路径
private string GetStream(string FilePath)
{
//建立文件流对象
System.IO.FileStream FileStr = new System.IO.FileStream(FilePath, System.IO.FileMode.Open);
byte[] by = new byte[System.Convert.ToInt32(FileStr.Length)];
FileStr.Read(by, 0, by.Length);
FileStr.Close();
return (System.Convert.ToBase64String(by));
}
///
/// SMTP回应代码哈希表
///

private void SMTPCodeAdd()
{
//[RFC 821 4.2.1.]
/*
4.2.2. NUMERIC ORDER LIST OF REPLY CODES
211 System status, or system help reply
214 Help message
[Information on how to use the receiver or the meaning of a
particular non-standard command; this reply is useful only
to the human user]
220 Service ready
221 Service closing transmission channel
250 Requested mail action okay, completed
251 User not local; will forward to

354 Start mail input; end with .

421 Service not available,
closing transmission channel
[This may be a reply to any command if the service knows it
must shut down]
450 Requested mail action not taken: mailbox unavailable
[E.g., mailbox busy]
451 Requested action aborted: local error in processing
452 Requested action not taken: insufficient system storage

500 Syntax error, command unrecognized
[This may include errors such as command line too long]
501 Syntax error in parameters or arguments
502 Command not implemented
503 Bad sequence of commands
504 Command parameter not implemented
550 Requested action not taken: mailbox unavailable
[E.g., mailbox not found, no access]
551 User not local; please try
552 Requested mail action aborted: exceeded storage allocation
553 Requested action not taken: mailbox name not allowed
[E.g., mailbox syntax incorrect]
554 Transaction failed

*/
ErrCodeHT.Add("421", "服务未就绪,关闭传输信道");
ErrCodeHT.Add("432", "需要一个密码转换");
ErrCodeHT.Add("450", "要求的邮件操作未完成,邮箱不可用(例如,邮箱忙)");
ErrCodeHT.Add("451", "放弃要求的操作;处理过程中出错");
ErrCodeHT.Add("452", "系统存储不足,要求的操作未执行");
ErrCodeHT.Add("454", "临时认证失败");
ErrCodeHT.Add("500", "邮箱地址错误");
ErrCodeHT.Add("501", "参数格式错误");
ErrCodeHT.Add("502", "命令不可实现");
ErrCodeHT.Add("503", "服务器需要SMTP验证");
ErrCodeHT.Add("504", "命令参数不可实现");
ErrCodeHT.Add("530", "需要认证");
ErrCodeHT.Add("534", "认证机制过于简单");
ErrCodeHT.Add("538", "当前请求的认证机制需要加密");
ErrCodeHT.Add("550", "要求的邮件操作未完成,邮箱不可用(例如,邮箱未找到,或不可访问)");
ErrCodeHT.Add("551", "用户非本地,请尝试");
ErrCodeHT.Add("552", "过量的存储分配,要求的操作未执行");
ErrCodeHT.Add("553", "邮箱名不可用,要求的操作未执行(例如邮箱格式错误)");
ErrCodeHT.Add("554", "传输失败");

/*
211 System status, or system help reply
214 Help message
[Information on how to use the receiver or the meaning of a
particular non-standard command; this reply is useful only
to the human user]
220 Service ready
221 Service closing transmission channel
250 Requested mail action okay, completed
251 User not local; will forward to

354 Start mail input; end with .
*/
RightCodeHT.Add("220", "服务就绪");
RightCodeHT.Add("221", "服务关闭传输信道");
RightCodeHT.Add("235", "验证成功");
RightCodeHT.Add("250", "要求的邮件操作完成");
RightCodeHT.Add("251", "非本地用户,将转发向");
RightCodeHT.Add("334", "服务器响应验证Base64字符串");
RightCodeHT.Add("354", "开始邮件输入,以.结束");
}
///
/// 发送SMTP命令
///

private bool SendCommand(string str)
{
byte[] WriteBuffer;
if (str == null || str.Trim() == String.Empty)
{
return true;
}
logs += str;
WriteBuffer = Encoding.Default.GetBytes(str);
try
{
networkStream.Write(WriteBuffer, 0, WriteBuffer.Length);
}
catch
{
errmsg = "网络连接错误";
return false;
}
return true;
}
///
/// 接收SMTP服务器回应
///

private string RecvResponse()
{
int StreamSize;
string Returnvalue = String.Empty;
byte[] ReadBuffer = new byte[1024];
try
{
StreamSize = networkStream.Read(ReadBuffer, 0, ReadBuffer.Length);
}
catch
{
errmsg = "网络连接错误";
return "false";
}
if (StreamSize == 0)
{
return Returnvalue;
}
else
{
Returnvalue = Encoding.Default.GetString(ReadBuffer).Substring(0, StreamSize);
logs += Returnvalue + this.CRLF;
return Returnvalue;
}
}
///
/// 与服务器交互,发送一条命令并接收回应。
///

/// 一个要发送的命令
/// 如果错误,要反馈的信息
private bool Dialog(string str, string errstr)
{
if (str == null || str.Trim() == string.Empty)
{
return true;
}
if (SendCommand(str))
{
string RR = RecvResponse();
if (RR == "false")
{
return false;
}
//检查返回的代码,根据[RFC 821]返回代码为3位数字代码如220
string RRCode = RR.Substring(0, 3);
if (RightCodeHT[RRCode] != null)
{
return true;
}
else
{
if (ErrCodeHT[RRCode] != null)
{
errmsg += (RRCode + ErrCodeHT[RRCode].ToString());
errmsg += CRLF;
}
else
{
errmsg += RR;
}
errmsg += errstr;
return false;
}
}
else
{
return false;
}
}

///
/// 与服务器交互,发送一组命令并接收回应。
///

private bool Dialog(string[] str, string errstr)
{
for (int i = 0; i < str.Length; i++)
{
if (!Dialog(str[i], ""))
{
errmsg += CRLF;
errmsg += errstr;
return false;
}
}
return true;
}

//连接服务器
private bool Connect(string smtpServer, int port)
{
//创建Tcp连接
try
{
tcpClient = new TcpClient(smtpServer, port);
}
catch (Exception e)
{
errmsg = e.ToString();
return false;
}
networkStream = tcpClient.GetStream();
//验证网络连接是否正确
if (RightCodeHT[RecvResponse().Substring(0, 3)] == null)
{
errmsg = "网络连接失败";
return false;
}
return true;
}
private string GetPriorityString(MailPriority mailPriority)
{
string priority = "Normal";
if (mailPriority == MailPriority.Low)
{
priority = "Low";
}
else if (mailPriority == MailPriority.High)
{
priority = "High";
}
return priority;
}
///
/// 发送电子邮件,SMTP服务器不需要身份验证
///

///
///
///
///
public bool SendEmail(string smtpServer, int port, MailMessage mailMessage)
{
return SendEmail(smtpServer, port, false, "", "", mailMessage);
}
///
/// 发送电子邮件,SMTP服务器需要身份验证
///

///
///
///
///
///
///
public bool SendEmail(string smtpServer, int port, string username, string password, MailMessage mailMessage)
{
return SendEmail(smtpServer, port, false, username, password, mailMessage);
}
private bool SendEmail(string smtpServer, int port, bool ESmtp, string username, string password, MailMessage mailMessage)
{
if (Connect(smtpServer, port) == false)//测试连接服务器是否成功
return false;
string priority = GetPriorityString(mailMessage.Priority);
bool Html = (mailMessage.BodyFormat == MailFormat.HTML);

string[] SendBuffer;
string SendBufferstr;
//进行SMTP验证,现在大部分SMTP服务器都要认证
if (ESmtp)
{
SendBuffer = new String[4];
SendBuffer[0] = "EHLO " + smtpServer + CRLF;
SendBuffer[1] = "AUTH LOGIN" + CRLF;
SendBuffer[2] = Base64Encode(username) + CRLF;
SendBuffer[3] = Base64Encode(password) + CRLF;
if (!Dialog(SendBuffer, "SMTP服务器验证失败,请核对用户名和密码。"))
return false;
}
else
{//不需要身份认证
SendBufferstr = "HELO " + smtpServer + CRLF;
if (!Dialog(SendBufferstr, ""))
return false;
}
//发件人地址
SendBufferstr = "MAIL FROM:<" + mailMessage.From + ">" + CRLF;
if (!Dialog(SendBufferstr, "发件人地址错误,或不能为空"))
return false;
//收件人地址
SendBuffer = new string[mailMessage.Recipients.Count];
for (int i = 0; i < mailMessage.Recipients.Count; i++)
{
SendBuffer[i] = "RCPT TO:<" + (string)mailMessage.Recipients[i] + ">" + CRLF;
}
if (!Dialog(SendBuffer, "收件人地址有误"))
return false;
/*
SendBuffer=new string[10];
for(int i=0;i {
SendBuffer[i]="RCPT TO:<" + RecipientBCC[i].ToString() +">" + CRLF;
}
if(!Dialog(SendBuffer,"密件收件人地址有误"))
return false;
*/
SendBufferstr = "DATA" + CRLF;
if (!Dialog(SendBufferstr, ""))
return false;
//发件人姓名
SendBufferstr = "From:" + mailMessage.FromName + "<" + mailMessage.From + ">" + CRLF;
//if(ReplyTo.Trim()!="")
//{
// SendBufferstr+="Reply-To: " + ReplyTo + CRLF;
//}
//SendBufferstr+="To:" + ToName + "<" + Recipient[0] +">" +CRLF;
//至少要有一个收件人
if (mailMessage.Recipients.Count == 0)
{
return false;
}
else
{
SendBufferstr += "To:=?" + mailMessage.Charset.ToUpper() + "?B?" +
Base64Encode((string)mailMessage.Recipients[0]) + "?=" + "<" + (string)mailMessage.Recipients[0] + ">" + CRLF;
}

//SendBufferstr+="CC:";
//for(int i=0;i //{
// SendBufferstr+=Recipient[i].ToString() + "<" + Recipient[i].ToString() +">,";
//}
//SendBufferstr+=CRLF;
SendBufferstr +=
((mailMessage.Subject == String.Empty || mailMessage.Subject == null) ? "Subject:" : ((mailMessage.Charset == "") ? ("Subject:" +
mailMessage.Subject) : ("Subject:" + "=?" + mailMessage.Charset.ToUpper() + "?B?" +
Base64Encode(mailMessage.Subject) + "?="))) + CRLF;
SendBufferstr += "X-Priority:" + priority + CRLF;
SendBufferstr += "X-MSMail-Priority:" + priority + CRLF;
SendBufferstr += "Importance:" + priority + CRLF;
SendBufferstr += "X-Mailer: Lion.Web.Mail.SmtpMail Pubclass [cn]" + CRLF;
SendBufferstr += "MIME-Version: 1.0" + CRLF;
if (mailMessage.Attachments.Count != 0)
{
SendBufferstr += "Content-Type: multipart/mixed;" + CRLF;
SendBufferstr += " boundary=\"=====" +
(Html ? "001_Dragon520636771063_" : "001_Dragon303406132050_") + "=====\"" + CRLF + CRLF;
}
if (Html)
{
if (mailMessage.Attachments.Count == 0)
{
SendBufferstr += "Content-Type: multipart/alternative;" + CRLF;//内容格式和分隔符
SendBufferstr += " boundary=\"=====003_Dragon520636771063_=====\"" + CRLF + CRLF;
SendBufferstr += "This is a multi-part message in MIME format." + CRLF + CRLF;
}
else
{
SendBufferstr += "This is a multi-part message in MIME format." + CRLF + CRLF;
SendBufferstr += "--=====001_Dragon520636771063_=====" + CRLF;
SendBufferstr += "Content-Type: multipart/alternative;" + CRLF;//内容格式和分隔符
SendBufferstr += " boundary=\"=====003_Dragon520636771063_=====\"" + CRLF + CRLF;
}
SendBufferstr += "--=====003_Dragon520636771063_=====" + CRLF;
SendBufferstr += "Content-Type: text/plain;" + CRLF;
SendBufferstr += ((mailMessage.Charset == "") ? (" charset=\"iso-8859-1\"") : (" charset=\"" +
mailMessage.Charset.ToLower() + "\"")) + CRLF;
SendBufferstr += "Content-Transfer-Encoding: base64" + CRLF + CRLF;
SendBufferstr += Base64Encode("邮件内容为HTML格式,请选择HTML方式查看") + CRLF + CRLF;
SendBufferstr += "--=====003_Dragon520636771063_=====" + CRLF;

SendBufferstr += "Content-Type: text/html;" + CRLF;
SendBufferstr += ((mailMessage.Charset == "") ? (" charset=\"iso-8859-1\"") : (" charset=\"" +
mailMessage.Charset.ToLower() + "\"")) + CRLF;
SendBufferstr += "Content-Transfer-Encoding: base64" + CRLF + CRLF;
SendBufferstr += Base64Encode(mailMessage.Body) + CRLF + CRLF;
SendBufferstr += "--=====003_Dragon520636771063_=====--" + CRLF;
}
else
{
if (mailMessage.Attachments.Count != 0)
{
SendBufferstr += "--=====001_Dragon303406132050_=====" + CRLF;
}
SendBufferstr += "Content-Type: text/plain;" + CRLF;
SendBufferstr += ((mailMessage.Charset == "") ? (" charset=\"iso-8859-1\"") : (" charset=\"" +
mailMessage.Charset.ToLower() + "\"")) + CRLF;
SendBufferstr += "Content-Transfer-Encoding: base64" + CRLF + CRLF;
SendBufferstr += Base64Encode(mailMessage.Body) + CRLF;
}

//SendBufferstr += "Content-Transfer-Encoding: base64"+CRLF;
if (mailMessage.Attachments.Count != 0)
{
for (int i = 0; i < mailMessage.Attachments.Count; i++)
{
string filepath = (string)mailMessage.Attachments[i];
SendBufferstr += "--=====" +
(Html ? "001_Dragon520636771063_" : "001_Dragon303406132050_") + "=====" + CRLF;
//SendBufferstr += "Content-Type: application/octet-stream"+CRLF;
SendBufferstr += "Content-Type: text/plain;" + CRLF;
SendBufferstr += " name=\"=?" + mailMessage.Charset.ToUpper() + "?B?" +
Base64Encode(filepath.Substring(filepath.LastIndexOf("\\") + 1)) + "?=\"" + CRLF;
SendBufferstr += "Content-Transfer-Encoding: base64" + CRLF;
SendBufferstr += "Content-Disposition: attachment;" + CRLF;
SendBufferstr += " filename=\"=?" + mailMessage.Charset.ToUpper() + "?B?" +
Base64Encode(filepath.Substring(filepath.LastIndexOf("\\") + 1)) + "?=\"" + CRLF + CRLF;
SendBufferstr += GetStream(filepath) + CRLF + CRLF;
}
SendBufferstr += "--=====" +
(Html ? "001_Dragon520636771063_" : "001_Dragon303406132050_") + "=====--" + CRLF + CRLF;
}

SendBufferstr += CRLF + "." + CRLF;//内容结束
if (!Dialog(SendBufferstr, "错误信件信息"))
return false;
SendBufferstr = "QUIT" + CRLF;
if (!Dialog(SendBufferstr, "断开连接时错误"))
return false;
networkStream.Close();
tcpClient.Close();
return true;
}
}

public class SmtpMail
{
private static string _SmtpServer;
///
/// 格式:SmtpAccount:Password@SmtpServerAddress

/// 或者:SmtpServerAddress

///
/// SmtpMail.SmtpServer="user:12345678@smtp.126.com";
/// //或者:
/// SmtpMail.SmtpServer="smtp.126.com";
/// 或者:
/// SmtpMail.SmtpServer=SmtpServerHelper.GetSmtpServer("user","12345678","smtp.126.com");
///

///

public static string SmtpServer
{
set { _SmtpServer = value; }
get { return _SmtpServer; }
}
public static bool Send(MailMessage mailMessage, string username, string password)
{
SmtpServerHelper helper = new SmtpServerHelper();
return helper.SendEmail(_SmtpServer, 25, username, password, mailMessage);
}
}
#endregion
}
[/code]

[code]
csharp
using System;
using NUnit.Framework;

namespace SkyDev.Web.Mail
{
///
/// Test 的摘要说明。
///

[TestFixture]
public class TestSmtpMail
{
//安装测试用例,完成初始化操作
[SetUp]
public void SetUp()
{
}
//测试结束完成清理操作
[TearDown]
public void TearDown()
{

}

[Test]
public void TestMailAttachments()
{
SkyDev.Web.Mail.MailAttachments attachments = new MailAttachments();
Assert.AreEqual(0, attachments.Count, "初始化MailAttachments");
attachments.Add("c:\\autoexec.bat");
Assert.AreEqual(1, attachments.Count, "增加附件(附件确实存在)");
attachments.Add("c:\\autoexec.dat.txt");
Assert.AreEqual(1, attachments.Count, "增加附件(附件不存在)");
attachments.Clear();
Assert.AreEqual(0, attachments.Count, "清除附件");
}
[Test]
public void TestMailMessage()
{
MailMessage message = new MailMessage();
Assert.AreEqual(0, message.Attachments.Count, "初始化MailAttachments");
Assert.AreEqual(MailFormat.Text, message.BodyFormat, "邮件格式");
Assert.AreEqual("GB2312", message.Charset, "缺省的字符集");
}
[Test]
public void TestSendMail()
{
SmtpMail.SmtpServer = "smtp.126.com";
MailMessage mail = new MailMessage();
mail.From = "qs1976@126.com";
mail.FromName = "曾青松";
mail.AddRecipients("qs1976@126.com");
mail.Subject = "主题:测试邮件";
mail.BodyFormat = MailFormat.Text;
mail.Body = "测试的内容.";
mail.Attachments.Add("c:\\test.txt");
SmtpMail.Send(mail, "", "");//请填写自己的测试邮件帐号
}
}
}
[/code]