使用完全托管代码编写的 FTP 组件

• 下载 ftp 程序集项目 - 20 Kb
• 下载演示项目 - 10 Kb

最近，我需要编写一个程序，它可以自动从 FTP 服务器下载文件。不幸的是，.NET Framework 对 FTP 服务的支持不够好。虽然有一些公司已经编写了可以直接使用的库，但价格对于像我这样的人来说实在太高了。因此，我决定编写自己的 FTP 库，现在它完成了。

免责声明

这个 FTP 组件是我的设计的不完整实现，也没有经过充分的测试。请记住，它可能包含错误甚至设计缺陷。

连接到 FTP 服务器

FtpSession session = new FtpSession();
session.Server = "localhost";
session.Port   = 21; //not required if using the default ftp port 21
session.Connect("anonymous", "someone@somewhere.com");

枚举子目录和文件

/*
* It is possible an incorrect list will be returned.
* In this case, you need to add your own regular expression to 
* interpret the list result (try to find it within ftpdirectory.cs)
*/
FtpDirectory root = session.RootDirectory;
foreach(FtpDirectory d in root.SubDirectories)
    //do something

    foreach(FtpFile f in root.Files)
        //do something

        /*
         * Only CurrentDirectory's item can be legally used.
         * Do not save down FtpDirectory and FtpFile for later use
         * unless you are sure they belongs to CurrentDirectory.
         * Here is some sample may cause problems
         */
        FtpDirectory d1 = session.CurrentDirectory.FindSubdirectory("somesubdir");
        FtpDirectory d2 = session.CurrentDirectory.FindSubdirectory("othersubdir");
        session.CurrentDirectory = d2;
        
        /*
         * Following 2 line will cause problem since CurrentDirectory 
         * is not d1's parent anymore
         */
        foreach(FtpDirectory d in d1) 
            //dosomthing

更改当前目录

session.CurrentDirectory = somesubdirectory

上传文件

//Blocking call
session.CurrentDirectory.PutFile("somelocalfile");
    
//Async call using callback
session.CurrentDirectory.BeginPutFile("somelocalfile", +
    new FtpAsyncDelegate(yourcallback);
    
//Async call using event
session.EndPutFile += new FtpFileEventHandler(yourhandler);
session.CurrectDirectory.BeginPutFile("somelocalfile");
        
    //Manually upload the file
    FileInfo fi = new FileInfo(localfilefullpath);
    Stream r = File.OpenRead(fi.FullName);

    // actually will return a FtpOutputDataStream object
    Stream w = session.CurrentDirectory.CreateDataStream(fi.Name); 
    int readed;
    byte[] buff = new byte[4096];
    while((readed=r.Read(buff, 0, 4096) != 0)
	    w.Write(buff, 0, readed);
    /*
    * Must call FtpDataStream.Close().
    * This is because it will try to read the file transfer 
    * result from FTP server.
    */
    w.Close();
    s.Close();

下载文件

//Blocking call
session.CurrentDirectory.GetFile("someremotefile");
    
//Async call using callback
session.CurrentDirectory.BeginGetFile("someremotefile", + 
    new FtpAsyncDelegate(yourcallback);
    
//Async call using event
session.EngGetFile += new FtpFileEventHandler(yourhandler);
session.CurrectDirectory.BeginGetFile("someremotefile");

//Manually download a file
Stream r = File.OpenWrite(localfilepath);

    FtpFile remoteFile = session.CurrentDirectory.FindFile(remotefilename);
    Stream w = remoteFile.GetOutputDataStream();
    int readed;
    byte[] buff = new byte[4096];
    while((readed=r.Read(buff, 0, 4096) != 0)
        w.Write(buff, 0, readed);
    /*
    * Must call FtpDataStream.Close().
    * This is because it will try to read the file transfer 
    * result from FTP server.
    */
    w.Close();
    s.Close();

在 ftp 服务器上创建一个新文件

//method 1
session.CurrentDirectory.CreateFile(newfilename);
        
//method 2
Stream s = session.CurrentDirectory.CreateFileStream(newfilename);
// do something with s
s.Close();

从 ftp 服务器上删除文件

//method 1
session.CurrentDirectory.RemoveFile(remotefilename);
        
//method 2
IFtpItem item = session.CurrentDirectory.FindItem(remotefilename)
if(item != null)
    session.CurrentDirectory.RemoveItem(item);

删除子目录

//method 1
session.CurrentDirectory.RemoveSubdir(subdirectoryname);

//method 2
IFtpItem item = session.CurrentDirectory.FindItem(sub directoryname)
if(item != null)
    session.CurrentDirectory.RemoveItem(item);

刷新 ftp 目录的内容

/*
* If you have saved down some some directory item(subdir or ftpfile).
* They will become invalid after you refresh the directory
*/
FtpFile f = session.CurrentDirectory.FindFile(somefile);
         
// you can not leagally use f anymore after the following line
session.CurrentDirectory.Refresh();

重命名文件或目录

IFtpItem item = session.FindItem(directoryorfile);
if(item != null)
    session.RenameSubitem(item, newname);

已知限制

• 不支持主动模式
• 不支持代理服务器

更新

• 删除了 FileCollection 和 DirectoryCollection
• 添加了对 VB 的 for each 语句的支持
• VB 客户端现在可以直接使用 for each 语句访问 FtpDirectory.Files 和 FtpDirectory.SubDirectories。

如果您发现任何错误，请给我发送电子邮件。请至少包含您发现的错误的描述。如果包含测试程序甚至解决方案，那就更好了。

玩得开心。