C#访问远程主机资源的方法

柔光的暖阳◎ 2022-07-10 16:28 179阅读 0赞

原文地址：[http://www.cnblogs.com/h2appy/archive/2008/05/21/1204277.html][http_www.cnblogs.com_h2appy_archive_2008_05_21_1204277.html]  在此感谢原文作者。

最近要实现访问远程主机的共享目录中的一个文件。遇到了权限问题。google了一下，找到了几种解决方法，记录如下：  
  
一、调用Net use命令  
  
        // 使用方法：  
        //if (Connect("192.168.1.48", "用户名", "密码"))     
        //\{  
        //    File.Copy(@"\\\\192.168.1.48\\共享目录\\test.txt",   @"e:\\\\test.txt",   true);    
        //\}  
        public bool Connect(string remoteHost, string userName, string passWord)  
        \{  
            bool Flag = true;  
            Process proc = new Process();  
            proc.StartInfo.FileName = "cmd.exe";  
            proc.StartInfo.UseShellExecute = false;  
            proc.StartInfo.RedirectStandardInput = true;  
            proc.StartInfo.RedirectStandardOutput = true;  
            proc.StartInfo.RedirectStandardError = true;  
            proc.StartInfo.CreateNoWindow = true;  
            try  
            \{  
                proc.Start();  
                string command = @"net  use  \\\\" + remoteHost + "  " + passWord + "  " + "  /user:" + userName + ">NUL";  
                proc.StandardInput.WriteLine(command);  
                command = "exit";  
                proc.StandardInput.WriteLine(command);  
                while (proc.HasExited == false)  
                \{  
                    proc.WaitForExit(1000);  
                \}  
                string errormsg = proc.StandardError.ReadToEnd();  
                if (errormsg != "")  
                    Flag = false;  
                proc.StandardError.Close();  
            \}  
            catch (Exception ex)  
            \{  
                Flag = false;  
            \}  
            finally  
            \{  
                proc.Close();  
                proc.Dispose();  
            \}  
            return Flag;  
        \}  
  
  
  
二、调用WNetAddConnection2、WNetAddConnection3或者NetUseAdd函数，进行磁盘映射。  
  
using System;  
using System.Collections.Generic;  
using System.Text;         
using System.Runtime.InteropServices;

namespace WindowsApplication1  
\{  
    public class MyMap  
    \{  
        \[DllImport("mpr.dll", EntryPoint = "WNetAddConnection2")\]  
        public static extern uint WNetAddConnection2(  
            \[In\] NETRESOURCE lpNetResource,  
            string lpPassword,  
            string lpUsername,  
            uint dwFlags);  
          
        \[DllImport("Mpr.dll")\]  
        public static extern uint WNetCancelConnection2(  
            string lpName,  
            uint dwFlags,  
            bool fForce);  
          
        \[StructLayout(LayoutKind.Sequential)\]  
        public class NETRESOURCE  
        \{  
            public int dwScope;  
            public int dwType;  
            public int dwDisplayType;  
            public int dwUsage;  
            public string LocalName;  
            public string RemoteName;  
            public string Comment;  
            public string Provider;  
        \}

// remoteNetworkPath format:  @"\\\\192.168.1.48\\sharefolder"  
        // localDriveName format:     @"E:"  
        public static bool CreateMap(string userName, string password, string remoteNetworkPath, string localDriveName)  
        \{              
            NETRESOURCE myNetResource = new NETRESOURCE();  
            myNetResource.dwScope = 2;       //2:RESOURCE\_GLOBALNET  
            myNetResource.dwType = 1;        //1:RESOURCETYPE\_ANY  
            myNetResource.dwDisplayType = 3; //3:RESOURCEDISPLAYTYPE\_GENERIC  
            myNetResource.dwUsage = 1;       //1: RESOURCEUSAGE\_CONNECTABLE  
            myNetResource.LocalName = localDriveName;  
            myNetResource.RemoteName = remoteNetworkPath;  
            myNetResource.Provider = null;

uint nret = WNetAddConnection2(myNetResource, password, userName, 0);

if (nret == 0)  
                return true;  
            else  
                return false;  
        \}

// localDriveName format:     @"E:"  
        public static bool DeleteMap(string localDriveName)  
        \{  
            uint nret = WNetCancelConnection2(localDriveName, 1, true);

if (nret == 0)  
                return true;  
            else  
                return false;  
        \}

public void test()  
        \{  
            // 注意：  
            // remote、local、username的格式一定要正确，否则可能出现错误  
            string remote = @"\\\\192.168.1.48\\generals";  
            string local = @"P:";  
            string username = @"Domain\\UserName";  
            string password = @"Password";  
            bool ret = MyMap.CreateMap(username, password, remote, local);  
            if (ret)  
            \{  
                //do what you want:  
                // ...  
                //File.Copy("q:\\\\test.htm", "c:\\\\test.htm");

MyMap.DeleteMap(local);  
            \}  
        \}  
    \}  
\}  
  
三、使用WebClient类  
  
由于WebClient类可以上传下载文件，并且支持以http:、https:和file:开头的URI，所以可以用WebClient类来传输文件。  
添加System[.NET][]命名空间后使用如下代码下载文件：

private void Test1()  
        \{  
            try  
            \{  
                WebClient client = new WebClient();  
                NetworkCredential cred = new NetworkCredential("username", "password", "172.16.0.222");  
                client.Credentials = cred;  
                client.DownloadFile("file://172.16.0.222/test/111.txt", "111.txt");  
            \}  
            catch (Exception ex)  
            \{  
                // 如果网络很慢，而文件又很大，这时可能有超时异常（Time out）。  
            \}  
        \}

public void Test2()  
        \{  
            try  
            \{  
                WebClient client = new WebClient();  
                NetworkCredential cred = new NetworkCredential("username", "password", "domain");  
                client.Credentials = cred;  
                client.DownloadFile("file://172.16.0.222/test/111.txt", "111.txt");  
            \}  
            catch (Exception ex)  
            \{  
                // 如果网络很慢，而文件又很大，这时可能有超时异常（Time out）。  
            \}  
        \}

类似的还可以试试WebRequest、FileWebRequest等：  
  
                WebRequest req = WebRequest.Create("file://138.12.12.14/generals/test.htm");  
                NetworkCredential cred = new NetworkCredential("username", "password", "IP");  
                req.Credentials = cred;  
                WebResponse response = req.GetResponse();  
                Stream strm = response.GetResponseStream();  
                StreamReader r = new StreamReader(strm);  
                ... ...  
  
  
  
四、角色模拟  
  
using System;  
using System.Collections.Generic;  
using System.Text;  
using System.Runtime.InteropServices;  
using System.Security.Principal;  
using System.IO;

namespace Test  
\{  
    public class Test  
    \{  
        // logon types  
        const int LOGON32\_LOGON\_INTERACTIVE = 2;  
        const int LOGON32\_LOGON\_NETWORK = 3;  
        const int LOGON32\_LOGON\_NEW\_CREDENTIALS = 9;  
        // logon providers  
        const int LOGON32\_PROVIDER\_DEFAULT = 0;  
        const int LOGON32\_PROVIDER\_WINNT50 = 3;  
        const int LOGON32\_PROVIDER\_WINNT40 = 2;  
        const int LOGON32\_PROVIDER\_WINNT35 = 1;

\[DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)\]  
        public static extern int LogonUser(String lpszUserName,  
            String lpszDomain,  
            String lpszPassword,  
            int dwLogonType,  
            int dwLogonProvider,  
            ref IntPtr phToken);

\[DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)\]  
        public static extern int DuplicateToken(IntPtr hToken,  
            int impersonationLevel,  
            ref IntPtr hNewToken);

\[DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)\]  
        public static extern bool RevertToSelf();

\[DllImport("kernel32.dll", CharSet = CharSet.Auto)\]  
        public static extern bool CloseHandle(IntPtr handle);

private WindowsImpersonationContext impersonationContext;

public bool impersonateValidUser(String userName, String domain, String password)  
        \{  
            WindowsIdentity tempWindowsIdentity;  
            IntPtr token = IntPtr.Zero;  
            IntPtr tokenDuplicate = IntPtr.Zero;

if (RevertToSelf())  
            \{  
                // 这里使用LOGON32\_LOGON\_NEW\_CREDENTIALS来访问远程资源。  
                // 如果要（通过模拟用户获得权限）实现服务器程序，访问本地授权[数据库][Link 1]可  
                // 以用LOGON32\_LOGON\_INTERACTIVE  
                if (LogonUser(userName, domain, password, LOGON32\_LOGON\_NEW\_CREDENTIALS,  
                    LOGON32\_PROVIDER\_DEFAULT, ref token) != 0)  
                \{  
                    if (DuplicateToken(token, 2, ref tokenDuplicate) != 0)  
                    \{  
                        tempWindowsIdentity = new WindowsIdentity(tokenDuplicate);  
                        impersonationContext = tempWindowsIdentity.Impersonate();  
                        if (impersonationContext != null)  
                        \{  
                            System.AppDomain.CurrentDomain.SetPrincipalPolicy(PrincipalPolicy.WindowsPrincipal);  
                            IPrincipal pr = System.Threading.Thread.CurrentPrincipal;  
                            IIdentity id = pr.Identity;  
                            CloseHandle(token);  
                            CloseHandle(tokenDuplicate);  
                            return true;  
                        \}  
                    \}  
                \}  
            \}

if (token != IntPtr.Zero)  
                CloseHandle(token);

if (tokenDuplicate != IntPtr.Zero)  
                CloseHandle(tokenDuplicate);

return false;  
        \}

public void undoImpersonation()  
        \{  
            impersonationContext.Undo();  
        \}

public void TestFunc()  
        \{  
            bool isImpersonated = false;  
            try  
            \{  
                if (impersonateValidUser("UserName", "Domain", "Password"))  
                \{  
                    isImpersonated = true;  
                    //do what you want now, as the special user  
                    // ...  
                    File.Copy(@"\\\\192.168.1.48\\generals\\now.htm", "c:\\\\now.htm", true);  
                \}  
            \}  
            finally  
            \{  
                if (isImpersonated)  
                    undoImpersonation();  
            \}  
        \}  
    \}  
\}  
  
  
五、比较  
  
方法一通过调用Shell命令Net Use实现，有点笨拙。  
方法二和方法一有些相似之处。映射远程资源，然后访问。  
方法三由于会有超时异常出现，所以在网络速度快、传输小文件时是可以的。  
方法四通过身份模拟实现远程资源访问。一些服务器进程就是通过这种方式运行的。这种方法也是我的最爱。  
  
六、要注意的地方  
  
关于这几种方法，google后都可以找到一些文章。但是等到自己实际[测试][Link 2]时，有时会出现各种小错误，  
这些错误基本来源于两方面：  
  
1、函数的参数选择有问题，和自己的环境不相符。  
比如          
public static extern int LogonUser(String lpszUserName,  
            String lpszDomain,  
            String lpszPassword,  
            int dwLogonType,  
            int dwLogonProvider,  
            ref IntPtr phToken);  
中的dwLogonType，要访问远程资源就要用LOGON32\_LOGON\_NEW\_CREDENTIALS，  
要模拟本机用户就要用LOGON32\_LOGON\_INTERACTIVE。  
  
2、函数的参数格式有问题。  
  
    a、比如  
    public static extern int LogonUser(String lpszUserName,  
            String lpszDomain,  
            String lpszPassword,  
            int dwLogonType,  
            int dwLogonProvider,  
            ref IntPtr phToken);  
    中的lpszUserName、lpszDomain、lpszPassword就要写清楚。  
  
    我就在这遇到过问题，第一次测试时，远程服务器就是一台独立的文件服务器，这是我的调用方式：  
        LogonUser("myname", "192.168.1.48", "password", LOGON32\_LOGON\_NEW\_CREDENTIALS,  
                    LOGON32\_PROVIDER\_DEFAULT, ref token);  
  
    第二次测试时，远程服务器是域MyDomain中的一个成员服务器，提供文件服务。这时代码就应该是：  
        LogonUser("myname", "MyDomain", "password", LOGON32\_LOGON\_NEW\_CREDENTIALS,  
                    LOGON32\_PROVIDER\_DEFAULT, ref token);  
  
    注意，代码中是MyDomain而不是IP地址。  
  
  
    b、再如：  
  
    参考上面代码  
            string remote = @"\\\\192.168.1.48\\generals";  
            string local = @"P:";  
            string username = @"Domain\\UserName";  
            string password = @"Password";  
  
    如果@"\\\\192.168.1.48\\generals"变成@"\\\\192.168.1.48\\generals\\”就会出错；  
    如果是域中的用户，那么把@"Domain\\UserName"变成@"UserName"就会出错。

[http_www.cnblogs.com_h2appy_archive_2008_05_21_1204277.html]: http://www.cnblogs.com/h2appy/archive/2008/05/21/1204277.html
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