Asp.net给IIS的SMTP服务加上邮件组功能
通过本文你可以学习到如下：
1、.net 2.0的自定义配置
2、拷贝文件如何折中考虑多进程并发问题
3、怎样最简单的制作windows服务
4、怎样让IIS自带的smtp服务支持mail group功能先定义邮件组配置，如下
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<configSections>
<section name="MailGroup" type="WawaSoft.MailGroup.Config,MailGroupLib"/>
</configSections>
<MailGroup>
<Groups>
<add Dir="C:\Inetpub\mailroot\Mailbox\ms-onlytiancai\P3_all.mbx">
<Members>
<add Dir="C:\Inetpub\mailroot\Mailbox\ms-onlytiancai\P3_huhao.mbx"></add>
</Members>
</add>
</Groups>
</MailGroup>
</configuration>
其中Groups\add是可重复的，意思就是可以建立多个组，Members\add也是可重复的，意思是一个组可以有多个成员，dir属性就是邮件组或成员的收件箱目录，这段自定义配置的处理代码如下
using System.Configuration;
namespace WawaSoft.MailGroup
{
public class Config : ConfigurationSection
{
#region 单件实现
private static Config _config;
public static Config Instance
{
get
{
if (_config == null)
{
lock (typeof (Config))
{
if (_config == null)
_config = ConfigurationManager.GetSection("MailGroup") as Config;
}
}
return _config;
}
}
#endregion
MailGroup#region MailGroup
[ConfigurationProperty("Groups")]
internal GroupCollection Groups
{
get { return (GroupCollection) this["Groups"]; }
}
#endregion
#region Groups
internal class GroupCollection : ConfigurationElementCollection
{
public Group this[int index]
{
get { return (Group) BaseGet(index); }
}
public new Group this[string dir]
{
get { return (Group) BaseGet(dir); }
}
public override ConfigurationElementCollectionType CollectionType
{
get { return ConfigurationElementCollectionType.AddRemoveClearMap; }
}
protected override ConfigurationElement CreateNewElement()
{
return new Group();
}
protected override object GetElementKey(ConfigurationElement element)
{
return ((Group) element).Dir;
}
}
#endregion
Group#region Group
internal class Group : ConfigurationElement
{
[ConfigurationProperty("Dir")]
public string Dir
{
get { return (string) this["Dir"]; }
}
[ConfigurationProperty("Members")]
public MemberCollection Members
{
get { return (MemberCollection) this["Members"]; }
}
}
#endregion
Members#region Members
internal class MemberCollection : ConfigurationElementCollection
{
public Member this[int index]
{
get { return (Member) BaseGet(index); }
}
public new Member this[string dir]
{
get { return (Member) BaseGet(dir); }
}
protected override ConfigurationElement CreateNewElement()
{
return new Member();
}
protected override object GetElementKey(ConfigurationElement element)
{
return ((Member) element).Dir;
}
}
#endregion
Member#region Member
internal class Member : ConfigurationElement
{
[ConfigurationProperty("Dir")]
public string Dir
{
get { return (string) this["Dir"]; }
}
}
#endregion
}
}
然后就是读取配置，监控邮件组收件箱，复制到成员收件箱，如下
using System;
using System.IO;
using WawaSoft.Common;
using System.Threading;
namespace WawaSoft.MailGroup
{
public class MailWatcher
{
private static readonly ITracer _tracer = TracerFactory.GetTrace(typeof (MailWatcher));
public static void Start()
{
_tracer.Info("启动成功");
Config.GroupCollection collection = Config.Instance.Groups;
foreach (Config.Group group in collection)
{
if (!Directory.Exists(group.Dir))
{
_tracer.Info("{0}不存在\r\n", group.Dir);
continue;
}
FileSystemWatcher fileSystemWatcher =
new FileSystemWatcher(group.Dir, "*.eml");
_tracer.Info("监听{0}", group.Dir);
Config.Group group1 = group;
fileSystemWatcher.Created +=
delegate(object sender, FileSystemEventArgs e)
{
try
{
Config.MemberCollection members = group1.Members;
foreach (Config.Member member in members)
{
try
{
string target = string.Format("{0}\\{1}",
member.Dir, e.Name);
ReliableCopy(e.FullPath, target, 0);
_tracer.Info("copy {0} to {1}",
e.FullPath, target);
}
catch (Exception ex)
{
_tracer.Error(ex, "复制邮件出错");
}
}
File.Delete(e.FullPath);
}
catch (Exception ex2)
{
_tracer.Error(ex2, "执行出错");
}
};
fileSystemWatcher.EnableRaisingEvents = true;
}
}
private static void ReliableCopy(string path, string target, int retryCount)
{
if(retryCount>0)
_tracer.Warn("正在执行第{0}次重试:{1}",retryCount,target);
if (retryCount > 5)
throw new ApplicationException(string.Format(
"重试次数超过限制:{0}", target));
try
{
File.Copy(path, target, true);
}
catch (IOException) //捕获IO异常
{
Thread.Sleep(5000);
ReliableCopy(path,target, ++retryCount);
}
//其它异常直接抛给调用者
}
}
}
代 码很简单，但又时候邮件特别大的话，邮件组的收件箱接受邮件需要一定的时间，而文件刚创建就会触发FileSystemWatch的事件，就会开始尝试拷 贝复制文件，而要复制的文件，正在接受新的字节，写入到自身，这种情况下进行File.Copy会报该文件被其它进程使用，所以我们拷贝的时候如果遇到这 个错，可以重试5次，每次重试Sleep 5秒，这也是一个折中的办法，当然用try catch性能会查一些，你可以可以考虑用win32api来判断文件状态，再做个循环检查直到可以复制，当然是有这样的API的话。
然后创建一个Service类，如下
using System.ServiceProcess;
namespace WawaSoft.MailGroup
{
internal partial class Service1 : ServiceBase
{
public Service1()
{
InitializeComponent();
}
protected override void OnStart(string[] args)
{
MailWatcher.Start();
}
}
}
并 在属性面板里给服务设置ServiceName属性，点这个服务属性下面的“添加安装程序”按钮，会添加一个ProjectInstaller.cs类， 选中serviceProcessInstaller1，设置Accout为localsystem,选中serviceInstaller1，设置 DispayName和ServiceName为MailGroupService，把StartType设置为automatic，就是自动启动就行 了，这样就是一个windows服务了。
安装的使用用以下命令安装服务
C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\installutil MailGroupLib.exe
pause
最后在services.msc里启用服务就行了。
测试：用telnet给all@ms-onlytiancai发邮件，看huhao@ms-onlytiancai能否收到
freedom -