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 ZTSX.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！");
}
}
}