本文涉及的内容：
1：自己制作Pop3Helper
信件格式的处理有麻烦
2：使用现成的pop3类
LumiSoft.Net.POP3.Client;
有两种处理方法
3：使用IMAP收邮件
功能似乎更多，比起pop3来。
4：SMTP发送邮件
关于 Mailbox unavailable. The server response was: 5.7.1 Unable to relay for xx 的错误处理
自己写一个POP3的接收程序并不是很简单。主要问题就是如何处理信件的格式。
其处理方法不是太复杂，用一个tcp联接就可以了。
这是代码
public class Pop3Helper
{
string _pop3server;
string _user;
int _port;
string _pwd;
public TcpClient _server;
public NetworkStream _netStream;
public StreamReader _reader;
public string _data;
public byte[] _charData;
public string _CRLF = "\r\n";
private string _log;
public string LogMSG
{
get { return _log; }
}
/// <summary>
///
/// </summary>
/// <param name="server"></param>
/// <param name="port"></param>
/// <param name="user"></param>
/// <param name="pwd"></param>
public Pop3Helper(string server, int port, string user, string pwd)
{
_pop3server = server;
_port = port;
_user = user;
_pwd = pwd;
}
/// <summary>
/// connect
/// </summary>
public void Connect()
{
//create a tcp connection
_server = new TcpClient(_pop3server, _port);
//prepare
_netStream = _server.GetStream();
_reader = new StreamReader(_server.GetStream());
if (!CheckResult(_reader.ReadLine()))
throw new Exception("Connect Error");
//login
_data = "USER " + this._user + _CRLF;
_charData = System.Text.Encoding.ASCII.GetBytes(_data.ToCharArray());
_netStream.Write(_charData, 0, _charData.Length);
if (!CheckResult(_reader.ReadLine()))
throw new Exception("User Error");
_data = "PASS " + this._pwd + _CRLF;
_charData = System.Text.Encoding.ASCII.GetBytes(_data.ToCharArray());
_netStream.Write(_charData, 0, _charData.Length);
if (!CheckResult(_reader.ReadLine()))
throw new Exception("Pass Error");
}
/// <summary>
/// get message Numbers
/// </summary>
/// <returns></returns>
public int GetMailCount()
{
try
{
_data = "STAT" + _CRLF;
_charData = System.Text.Encoding.ASCII.GetBytes(_data.ToCharArray());
_netStream.Write(_charData, 0, _charData.Length);
string resp = _reader.ReadLine();
string[] tokens = resp.Split(new char[] { ' ' });
return Convert.ToInt32(tokens[1]);
}
catch (Exception ex)
{
return 0;
}
}
public string GetMail(int id)
{
string line;
string content = "";
try
{
//get by id
_data = "RETR " + id + _CRLF;
_charData = System.Text.Encoding.ASCII.GetBytes(_data.ToCharArray());
_netStream.Write(_charData, 0, _charData.Length);
line = _reader.ReadLine();
if (line[0] != '-')
{
//end with '.'
while (line != ".")
{
line = _reader.ReadLine();
content += line + "\r\n";
}
}
return content;
}
catch (Exception err)
{
Log(err.Message);
return "Error";
}
}
public void DeleteMail(int id)
{
_data = "DELE" + id + _CRLF;
_charData = System.Text.Encoding.ASCII.GetBytes(_data.ToCharArray());
_netStream.Write(_charData, 0, _charData.Length);
if (!CheckResult(_reader.ReadLine()))
throw new Exception("Delete Error");
}
/// <summary>
/// close connection
/// </summary>
public void Close()
{
_data = "QUIT" + _CRLF;
_charData = System.Text.Encoding.ASCII.GetBytes(_data.ToCharArray());
_netStream.Write(_charData, 0, _charData.Length);
//close
_netStream.Close();
_reader.Close();
}
private bool CheckResult(string reply)
{
Log(reply);
if (reply.IndexOf("+OK") > -1)
return true;
else
return false;
}
private void Log(string msg)
{
_log += msg + "\r\n";
}
}
。。。。。
但是这种方式的一个问题就是关于解析信件的格式。如果是附件的话，他也直接给出了二进制，不容易使用。
所以，可以使用一个现成的工具：LumiSoft.Net.POP3.Client。这里面已经给写好了实现，用起来也很简单。
这是一个简单的用法（这里使用了两种处理方式，前一种是不建议使用的）
。。
using (POP3_Client pop3 = new POP3_Client())
{
//与Pop3服务器建立连接
pop3.Connect(_popServer, _pop3port,false);
//验证身份
pop3.Authenticate(_user, _pwd, false);
//get all messages
POP3_MessagesInfo infos = pop3.GetMessagesInfo();
foreach (POP3_MessageInfo info in infos)
{
byte[] bytes = pop3.GetMessage(info.MessageNumber);
Mime mime = Mime.Parse(bytes);
HandleMail(mime);
//delete it at last
//pop3.DeleteMessage(info.MessageNumber);
}
//the second way to do it
//for (int i = 0; i < pop3.Messages.Count; i++)
//{
// byte[] bytes = pop3.Messages[i].MessageToByte();
// Mime mime = Mime.Parse(bytes);
// HandleMail(mime);
// //delete it at last
// //pop3.DeleteMessage(pop3.Messages[i].SequenceNumber);
//}。
。。。
取得的邮件可以这要给获得。
#region pop3
//string customer = mime.MainEntity.To.ToAddressListString();//cargo company
//string sender = mime.MainEntity.From.ToAddressListString();//this is customer who send
#endregion
string customer = MailboxesToString(envelope.To);//cargo company
string sender = MailboxesToString(envelope.From);//this is customer who send
。。。
除此之外，它提供的另外一个工具是IMAP，它操作起来更加方便。代码如下：
。
IMAP_Client clnt = new IMAP_Client();
try
{
clnt.Connect("mail.xx.com", 143, false);
clnt.Authenticate("user", "password");
string[] folders = clnt.GetFolders();//get all types
string folder = "Inbox";
clnt.SelectFolder(folder);
IMAP_SequenceSet sequence_set = new IMAP_SequenceSet();
// All messages
sequence_set.Parse(string.Format("{0}:{1}", 1, clnt.MessagesCount));
IMAP_FetchItem[] fetchItems = clnt.FetchMessages(
sequence_set,
IMAP_FetchItem_Flags.UID |
IMAP_FetchItem_Flags.MessageFlags | IMAP_FetchItem_Flags.Size |
IMAP_FetchItem_Flags.Envelope,
true, false
);
//int count =0;
foreach (IMAP_FetchItem fetchItem in fetchItems)
{
IMAP_Envelope envelope = fetchItem.Envelope;
//hanldle it, means read and search and reply
try
{
HandleMail(envelope);
//count++;
}
catch (Exception ex)
{
Log("Sys", ex.Message);
}
}
//delete it after hanlde
clnt.DeleteMessages(sequence_set, false);
//disconnect
clnt.Disconnect();
//MessageBox.Show(count.ToString() + " of " + fetchItems .Length+ " Success");
}
catch (Exception x)
{
Log("Sys", x.Message);
//MessageBox.Show(x.Message);
}
。。
上边都是如何收邮件。
关于如何发送邮件是比较简单的。这里提供两种方式。
第一种方式是使用网上的smtp。这种方式必须要提供用户名和密码。这个适合于web应用，使用的smtp也是网上的，我一般使用163的smtp，基本没有问题。
第二种方式是使用本地的smtp。不需要提供密码，用户也可以是不存在的（垃圾邮件是不是就是这么产生的？），但是必要要提供smtp端口号。
第二种方法测试的时候有时候会报错“Mailbox unavailable. The server response was: 5.7.1
Unable to relay for
xxx”，查过资料之后（在baidu上没找到，还是google信息多一点），才发现问题原来是IIS里SMTP服务的配置有问题。
这样修改可以解决：到开SMTP属性—>Access页面Reply Restrictions/ Reply-Only this Below选项，加上自己的ip：127.0.0.1（允许本机，使用loalhost，如果是允许其他机器，类似设置）
代码如下
public class EMail
{
static public string accountName;
static public string password;
static public string smtpServer;
static public int smtpPort;
/// <summary>
/// need password,username, smtpserver
/// </summary>
/// <param name="to"></param>
/// <param name="subject"></param>
/// <param name="body"></param>
static public void SendMail(string sendTo, string subject, string body)
{
//.net smtp
System.Web.Mail.MailMessage mailmsg = new System.Web.Mail.MailMessage();
mailmsg.To = sendTo;
//mailmsg.Cc = cc;
mailmsg.Subject = subject;
mailmsg.Body = body;
//sender here
mailmsg.From = EMail.accountName;
// certify needed
mailmsg.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpauthenticate", "1");//1 is to certify
//the user id
mailmsg.Fields.Add(
"http://schemas.microsoft.com/cdo/configuration/sendusername",
EMail.accountName);
//the password
mailmsg.Fields.Add(
"http://schemas.microsoft.com/cdo/configuration/sendpassword",
EMail.password);
System.Web.Mail.SmtpMail.SmtpServer = EMail.smtpServer;
System.Web.Mail.SmtpMail.Send(mailmsg);
}
#region send mail2
/// <summary>
/// need username,smtp,smtp port
/// </summary>
/// <param name="sendTo"></param>
/// <param name="subject"></param>
/// <param name="body"></param>
static public void SendMail2(string sendTo, string subject, string body)
{
System.Net.Mail.MailMessage msg = new System.Net.Mail.MailMessage();
msg.To.Add(sendTo);
msg.From = new System.Net.Mail.MailAddress(accountName );
msg.Subject = subject;
msg.SubjectEncoding = System.Text.Encoding.UTF8;
msg.Body = body;//
msg.BodyEncoding = System.Text.Encoding.UTF8;
msg.IsBodyHtml = false;
//msg.Priority = MailPriority.High;//
System.Net.Mail.SmtpClient client = new System.Net.Mail.SmtpClient();
client.Host = smtpServer;
client.Port = smtpPort;
//client.Credentials = new System.Net.NetworkCredential("user@xxx.com", "pass");
client.Send(msg);
}
#endregion
}