Pop3收取邮件

using System;

using System.Net.Sockets;

using System.Net;

using System.Security.Cryptography;

using System.IO;

// 类名：Pop3

// 功能：接收电子邮件

namespace Email {

/// <summary>

/// Pop3 的摘要说明。

/// </summary>

public class Pop3 {

private string mstrHost = null; //主机名称或IP地址

private int mintPort = 110; //主机的端口号（默认为110）

private TcpClient mtcpClient = null; //客户端

private NetworkStream mnetStream = null; //网络基础数据流

private StreamReader m_stmReader = null; //读取字节流

private string mstrStatMessage = null; //执行STAT命令后得到的消息（从中得到邮件数）

/// <summary>

/// 构造函数

/// </summary>

/// <remarks>一个邮件接收对象</remarks>

public Pop3() {

}

/// <summary>

/// 构造函数

/// </summary>

/// <param name="host">主机名称或IP地址</param>

public Pop3(string host) {

mstrHost = host;

}

/// <summary>

/// 构造函数

/// </summary>

/// <param name="host">主机名称或IP地址</param>

/// <param name="port">主机的端口号</param>

/// <remarks>一个邮件接收对象</remarks>

public Pop3(string host, int port) {

mstrHost = host;

mintPort = port;

}

#region 属性

/// <summary>

/// 主机名称或IP地址

/// </summary>

/// <remarks>主机名称或IP地址</remarks>

public string HostName {

get { return mstrHost; }

set { mstrHost = value; }

}

/// <summary>

/// 主机的端口号

/// </summary>

/// <remarks>主机的端口号</remarks>

public int Port {

get { return mintPort; }

set { mintPort = value; }

}

#endregion

#region 私有方法

/// <summary>

/// 向网络访问的基础数据流中写数据（发送命令码）

/// </summary>

/// <param name="netStream">可以用于网络访问的基础数据流</param>

/// <param name="command">命令行</param>

/// <remarks>向网络访问的基础数据流中写数据（发送命令码）</remarks>

private void WriteToNetStream(ref NetworkStream netStream, String command) {

string strToSend = command + "/r/n";

byte[] arrayToSend = System.Text.Encoding.ASCII.GetBytes(strToSend.ToCharArray());

netStream.Write(arrayToSend, 0, arrayToSend.Length);

}

/// <summary>

/// 检查命令行结果是否正确

/// </summary>

/// <param name="message">命令行的执行结果</param>

/// <param name="check">正确标志</param>

/// <returns>

/// 类型：布尔

/// 内容：true表示没有错误，false为有错误

/// </returns>

/// <remarks>检查命令行结果是否有错误</remarks>

private bool CheckCorrect(string message, string check) {

if (message.IndexOf(check) == -1)

return false;

else

return true;

}

/// <summary>

/// 邮箱中的未读邮件数

/// </summary>

/// <param name="message">执行完LIST命令后的结果</param>

/// <returns>

/// 类型：整型

/// 内容：邮箱中的未读邮件数

/// </returns>

/// <remarks>邮箱中的未读邮件数</remarks>

private int GetMailNumber(string message) {

string[] strMessage = message.Split(' ');

return Int32.Parse(strMessage[1]);

}

/// <summary>

/// 得到经过解码后的邮件的内容

/// </summary>

/// <param name="encodingContent">解码前的邮件的内容</param>

/// <returns>

/// 类型：字符串

/// 内容：解码后的邮件的内容

/// </returns>

/// <remarks>得到解码后的邮件的内容</remarks>

private string GetDecodeMailContent(string encodingContent) {

string strContent = encodingContent.Trim();

string strEncode = null;

int iStart = strContent.IndexOf("Base64");

if (iStart == -1)

throw new Pop3Exception("邮件内容不是Base64编码，请检查");

else {

strEncode = strContent.Substring(iStart + 6, strContent.Length - iStart - 6);

try {

return SX.Encode.TransformToString(strEncode);

} catch (SX.EncodeException exc) {

throw new Pop3Exception(exc.Message);

}

}

}

#endregion

/// <summary>

/// 与主机建立连接

/// </summary>

/// <returns>

/// 类型：布尔

/// 内容：连接结果（true为连接成功，false为连接失败）

/// </returns>

/// <remarks>与主机建立连接</remarks>

public bool Connect() {

if (mstrHost == null)

throw new Exception("请提供SMTP主机名称或IP地址！");

if (mintPort == 0)

throw new Exception("请提供SMTP主机的端口号");

try {

mtcpClient = new TcpClient(mstrHost, mintPort);

mnetStream = mtcpClient.GetStream();

m_stmReader = new StreamReader(mtcpClient.GetStream());

string strMessage = m_stmReader.ReadLine();

if (CheckCorrect(strMessage, "+OK") == true)

return true;

else

return false;

} catch (SocketException exc) {

throw new Pop3Exception(exc.ToString());

} catch (NullReferenceException exc) {

throw new Pop3Exception(exc.ToString());

}

}

#region Pop3命令

/// <summary>

/// 执行Pop3命令，并检查执行的结果

/// </summary>

/// <param name="command">Pop3命令行</param>

/// <returns>

/// 类型：字符串

/// 内容：Pop3命令的执行结果

/// </returns>

private string ExecuteCommand(string command) {

string strMessage = null; //执行Pop3命令后返回的消息

try {

//发送命令

WriteToNetStream(ref mnetStream, command);

//读取多行

if (command.Substring(0, 4).Equals("LIST") || command.Substring(0, 4).Equals("RETR") || command.Substring(0, 4).Equals("UIDL")) //记录STAT后的消息（其中包含邮件数）

{

strMessage = ReadMultiLine();

if (command.Equals("LIST")) //记录LIST后的消息（其中包含邮件数）

mstrStatMessage = strMessage;

}

//读取单行

else

strMessage = m_stmReader.ReadLine();

//判断执行结果是否正确

if (CheckCorrect(strMessage, "+OK"))

return strMessage;

else

return "Error";

} catch (IOException exc) {

throw new Pop3Exception(exc.ToString());

}

}

/// <summary>

/// 在Pop3命令中，LIST、RETR和UIDL命令的结果要返回多行，以点号（.）结尾，

/// 所以如果想得到正确的结果，必须读取多行

/// </summary>

/// <returns>

/// 类型：字符串

/// 内容：执行Pop3命令后的结果

/// </returns>

private string ReadMultiLine() {

string strMessage = m_stmReader.ReadLine();

string strTemp = null;

while (strMessage != ".") {

strTemp = strTemp + strMessage;

strMessage = m_stmReader.ReadLine();

}

return strTemp;

}

//USER命令

private string USER(string user) {

return ExecuteCommand("USER " + user) + "/r/n";

}

//PASS命令

private string PASS(string password) {

return ExecuteCommand("PASS " + password) + "/r/n";

}

//LIST命令

private string LIST() {

return ExecuteCommand("LIST") + "/r/n";

}

//UIDL命令

private string UIDL() {

return ExecuteCommand("UIDL") + "/r/n";

}

//NOOP命令

private string NOOP() {

return ExecuteCommand("NOOP") + "/r/n";

}

//STAT命令

private string STAT() {

return ExecuteCommand("STAT") + "/r/n";

}

//RETR命令

private string RETR(int number) {

return ExecuteCommand("RETR " + number.ToString()) + "/r/n";

}

//DELE命令

private string DELE(int number) {

return ExecuteCommand("DELE " + number.ToString()) + "/r/n";

}

//QUIT命令

private void Quit() {

WriteToNetStream(ref mnetStream, "QUIT");

}

/// <summary>

/// 收取邮件

/// </summary>

/// <param name="user">用户名</param>

/// <param name="password">口令</param>

/// <returns>

/// 类型：字符串数组

/// 内容：解码前的邮件内容

/// </returns>

private string[] ReceiveMail(string user, string password) {

int iMailNumber = 0; //邮件数

if (USER(user).Equals("Error"))

throw new Pop3Exception("用户名不正确！");

if (PASS(password).Equals("Error"))

throw new Pop3Exception("用户口令不正确！");

if (STAT().Equals("Error"))

throw new Pop3Exception("准备接收邮件时发生错误！");

if (LIST().Equals("Error"))

throw new Pop3Exception("得到邮件列表时发生错误！");

try {

iMailNumber = GetMailNumber(mstrStatMessage);

//没有新邮件

if (iMailNumber == 0)

return null;

else {

string[] strMailContent = new string[iMailNumber];

for (int i = 1; i <= iMailNumber; i++) {

//读取邮件内容

strMailContent[i - 1] = GetDecodeMailContent(RETR(i));

}

return strMailContent;

}

} catch (Pop3Exception exc) {

throw new Pop3Exception(exc.ToString());

}

}

#endregion

/// <summary>

/// 收取邮件

/// </summary>

/// <param name="user">用户名</param>

/// <param name="password">口令</param>

/// <returns>

/// 类型：字符串数组

/// 内容：解码前的邮件内容

/// </returns>

///<remarks>收取邮箱中的未读邮件</remarks>

public string[] Receive(string user, string password) {

try {

return ReceiveMail(user, password);

} catch (Pop3Exception exc) {

throw new Pop3Exception(exc.ToString());

}

}

/// <summary>

/// 断开所有与服务器的会话

/// </summary>

/// <remarks>断开所有与服务器的会话</remarks>

public void DisConnect() {

try {

Quit();

if (m_stmReader != null)

m_stmReader.Close();

if (mnetStream != null)

mnetStream.Close();

if (mtcpClient != null)

mtcpClient.Close();

} catch (SocketException exc) {

throw new Pop3Exception(exc.ToString());

}

}

/// <summary>

/// 删除邮件

/// </summary>

/// <param name="number">邮件号</param>

public void DeleteMail(int number) {

//删除邮件

int iMailNumber = number + 1;

if (DELE(iMailNumber).Equals("Error"))

throw new Pop3Exception("删除第" + iMailNumber.ToString() + "时出现错误！");

}

}

}