命名管道提供管道服务器与一个或多个管道客户端之间的进程间通信。 它们提供的功能比匿名管道更多，这些管道在本地计算机上提供进程间通信。 命名管道支持通过网络和多个服务器实例、基于消息的通信和客户端模拟进行全双工通信，这样连接进程就可以在远程服务器上使用自己的权限集。
重要
Linux 上的 .NET 使用 Unix 域套接字（UDS）来实现这些 API。
若要实现名称管道，请使用 NamedPipeServerStream 和 NamedPipeClientStream 类。
示例 1
以下示例演示如何使用 NamedPipeServerStream 类创建命名管道。 在此示例中，服务器进程创建四个线程。 每个线程都可以接受客户端连接。 然后，连接的客户端进程会向服务器提供文件名。 如果客户端具有足够的权限，则服务器进程将打开文件并将其内容发送回客户端。
using System;
using System.IO;
using System.IO.Pipes;
using System.Text;
using System.Threading;
public class PipeServer
{
private static int numThreads = 4;
public static void Main()
{
int i;
Thread?[] servers = new Thread[numThreads];
Console.WriteLine("\n*** Named pipe server stream with impersonation example ***\n");
Console.WriteLine("Waiting for client connect...\n");
for (i = 0; i < numThreads; i++)
{
servers[i] = new Thread(ServerThread);
servers[i]?.Start();
}
Thread.Sleep(250);
while (i > 0)
{
for (int j = 0; j < numThreads; j++)
{
if (servers[j] != null)
{
if (servers[j]!.Join(250))
{
Console.WriteLine($"Server thread[{servers[j]!.ManagedThreadId}] finished.");
servers[j] = null;
i--; // decrement the thread watch count
}
}
}
}
Console.WriteLine("\nServer threads exhausted, exiting.");
}
private static void ServerThread(object? data)
{
NamedPipeServerStream pipeServer =
new NamedPipeServerStream("testpipe", PipeDirection.InOut, numThreads);
int threadId = Thread.CurrentThread.ManagedThreadId;
// Wait for a client to connect
pipeServer.WaitForConnection();
Console.WriteLine($"Client connected on thread[{threadId}].");
try
{
// Read the request from the client. Once the client has
// written to the pipe its security token will be available.
StreamString ss = new StreamString(pipeServer);
// Verify our identity to the connected client using a
// string that the client anticipates.
ss.WriteString("I am the one true server!");
string filename = ss.ReadString();
// Read in the contents of the file while impersonating the client.
ReadFileToStream fileReader = new ReadFileToStream(ss, filename);
// Display the name of the user we are impersonating.
Console.WriteLine($"Reading file: {filename} on thread[{threadId}] as user: {pipeServer.GetImpersonationUserName()}.");
pipeServer.RunAsClient(fileReader.Start);
}
// Catch the IOException that is raised if the pipe is broken
// or disconnected.
catch (IOException e)
{
Console.WriteLine($"ERROR: {e.Message}");
}
pipeServer.Close();
}
}
// Defines the data protocol for reading and writing strings on our stream
public class StreamString
{
private Stream ioStream;
private UnicodeEncoding streamEncoding;
public StreamString(Stream ioStream)
{
this.ioStream = ioStream;
streamEncoding = new UnicodeEncoding();
}
public string ReadString()
{
int len = 0;
len = ioStream.ReadByte() * 256;
len += ioStream.ReadByte();
byte[] inBuffer = new byte[len];
ioStream.Read(inBuffer, 0, len);
return streamEncoding.GetString(inBuffer);
}
public int WriteString(string outString)
{
byte[] outBuffer = streamEncoding.GetBytes(outString);
int len = outBuffer.Length;
if (len > UInt16.MaxValue)
{
len = (int)UInt16.MaxValue;
}
ioStream.WriteByte((byte)(len / 256));
ioStream.WriteByte((byte)(len & 255));
ioStream.Write(outBuffer, 0, len);
ioStream.Flush();
return outBuffer.Length + 2;
}
}
// Contains the method executed in the context of the impersonated user
public class ReadFileToStream
{
private string fn;
private StreamString ss;
public ReadFileToStream(StreamString str, string filename)
{
fn = filename;
ss = str;
}
public void Start()
{
string contents = File.ReadAllText(fn);
ss.WriteString(contents);
}
}
Imports System.IO
Imports System.IO.Pipes
Imports System.Text
Imports System.Threading
Public Class PipeServer
Private Shared numThreads As Integer = 4
Public Shared Sub Main()
Dim i As Integer
Dim servers(numThreads) As Thread
Console.WriteLine(vbCrLf + "*** Named pipe server stream with impersonation example ***" + vbCrLf)
Console.WriteLine("Waiting for client connect..." + vbCrLf)
For i = 0 To numThreads - 1
servers(i) = New Thread(AddressOf ServerThread)
servers(i).Start()
Next i
Thread.Sleep(250)
While i > 0
For j As Integer = 0 To numThreads - 1
If Not (servers(j) Is Nothing) Then
If servers(j).Join(250) Then
Console.WriteLine("Server thread[{0}] finished.", servers(j).ManagedThreadId)
servers(j) = Nothing
i -= 1 ' decrement the thread watch count
End If
End If
Next j
End While
Console.WriteLine(vbCrLf + "Server threads exhausted, exiting.")
End Sub
Private Shared Sub ServerThread(data As Object)
Dim pipeServer As New _
NamedPipeServerStream("testpipe", PipeDirection.InOut, numThreads)
Dim threadId As Integer = Thread.CurrentThread.ManagedThreadId
' Wait for a client to connect
pipeServer.WaitForConnection()
Console.WriteLine("Client connected on thread[{0}].", threadId)
Try
' Read the request from the client. Once the client has
' written to the pipe its security token will be available.
Dim ss As new StreamString(pipeServer)
' Verify our identity to the connected client using a
' string that the client anticipates.
ss.WriteString("I am the one true server!")
Dim filename As String = ss.ReadString()
' Read in the contents of the file while impersonating the client.
Dim fileReader As New ReadFileToStream(ss, filename)
' Display the name of the user we are impersonating.
Console.WriteLine("Reading file: {0} on thread[{1}] as user: {2}.",
filename, threadId, pipeServer.GetImpersonationUserName())
pipeServer.RunAsClient(AddressOf fileReader.Start)
' Catch the IOException that is raised if the pipe is broken
' or disconnected.
Catch e As IOException
Console.WriteLine("ERROR: {0}", e.Message)
End Try
pipeServer.Close()
End Sub
End Class
' Defines the data protocol for reading and writing strings on our stream
Public Class StreamString
Private ioStream As Stream
Private streamEncoding As UnicodeEncoding
Public Sub New(ioStream As Stream)
Me.ioStream = ioStream
streamEncoding = New UnicodeEncoding(False, False)
End Sub
Public Function ReadString() As String
Dim len As Integer = 0
len = CType(ioStream.ReadByte(), Integer) * 256
len += CType(ioStream.ReadByte(), Integer)
Dim inBuffer As Array = Array.CreateInstance(GetType(Byte), len)
ioStream.Read(inBuffer, 0, len)
Return streamEncoding.GetString(CType(inBuffer, Byte()))
End Function
Public Function WriteString(outString As String) As Integer
Dim outBuffer() As Byte = streamEncoding.GetBytes(outString)
Dim len As Integer = outBuffer.Length
If len > UInt16.MaxValue Then
len = CType(UInt16.MaxValue, Integer)
End If
ioStream.WriteByte(CType(len \ 256, Byte))
ioStream.WriteByte(CType(len And 255, Byte))
ioStream.Write(outBuffer, 0, outBuffer.Length)
ioStream.Flush()
Return outBuffer.Length + 2
End Function
End Class
' Contains the method executed in the context of the impersonated user
Public Class ReadFileToStream
Private fn As String
Private ss As StreamString
Public Sub New(str As StreamString, filename As String)
fn = filename
ss = str
End Sub
Public Sub Start()
Dim contents As String = File.ReadAllText(fn)
ss.WriteString(contents)
End Sub
End Class
示例 2
以下示例演示使用该类的 NamedPipeClientStream 客户端进程。 客户端连接到服务器进程，并将文件名发送到服务器。 该示例使用模拟，因此运行客户端应用程序的标识必须具有访问文件的权限。 然后，服务器会将文件的内容发送回客户端。 然后，文件内容会显示到控制台。
using System;
using System.Diagnostics;
using System.IO;
using System.IO.Pipes;
using System.Security.Principal;
using System.Text;
using System.Threading;
public class PipeClient
{
private static int numClients = 4;
public static void Main(string[] args)
{
if (args.Length > 0)
{
if (args[0] == "spawnclient")
{
var pipeClient =
new NamedPipeClientStream(".", "testpipe",
PipeDirection.InOut, PipeOptions.None,
TokenImpersonationLevel.Impersonation);
Console.WriteLine("Connecting to server...\n");
pipeClient.Connect();
var ss = new StreamString(pipeClient);
// Validate the server's signature string.
if (ss.ReadString() == "I am the one true server!")
{
// The client security token is sent with the first write.
// Send the name of the file whose contents are returned
// by the server.
ss.WriteString("c:\\textfile.txt");
// Print the file to the screen.
Console.Write(ss.ReadString());
}
else
{
Console.WriteLine("Server could not be verified.");
}
pipeClient.Close();
// Give the client process some time to display results before exiting.
Thread.Sleep(4000);
}
}
else
{
Console.WriteLine("\n*** Named pipe client stream with impersonation example ***\n");
StartClients();
}
}
// Helper function to create pipe client processes
private static void StartClients()
{
string currentProcessName = Environment.CommandLine;
// Remove extra characters when launched from Visual Studio
currentProcessName = currentProcessName.Trim('"', ' ');
currentProcessName = Path.ChangeExtension(currentProcessName, ".exe");
Process?[] plist = new Process?[numClients];
Console.WriteLine("Spawning client processes...\n");
if (currentProcessName.Contains(Environment.CurrentDirectory))
{
currentProcessName = currentProcessName.Replace(Environment.CurrentDirectory, String.Empty);
}
// Remove extra characters when launched from Visual Studio
currentProcessName = currentProcessName.Replace("\\", String.Empty);
currentProcessName = currentProcessName.Replace("\"", String.Empty);
int i;
for (i = 0; i < numClients; i++)
{
// Start 'this' program but spawn a named pipe client.
plist[i] = Process.Start(currentProcessName, "spawnclient");
}
while (i > 0)
{
for (int j = 0; j < numClients; j++)
{
if (plist[j] != null)
{
if (plist[j]!.HasExited)
{
Console.WriteLine($"Client process[{plist[j]?.Id}] has exited.");
plist[j] = null;
i--; // decrement the process watch count
}
else
{
Thread.Sleep(250);
}
}
}
}
Console.WriteLine("\nClient processes finished, exiting.");
}
}
// Defines the data protocol for reading and writing strings on our stream.
public class StreamString
{
private Stream ioStream;
private UnicodeEncoding streamEncoding;
public StreamString(Stream ioStream)
{
this.ioStream = ioStream;
streamEncoding = new UnicodeEncoding();
}
public string ReadString()
{
int len;
len = ioStream.ReadByte() * 256;
len += ioStream.ReadByte();
var inBuffer = new byte[len];
ioStream.Read(inBuffer, 0, len);
return streamEncoding.GetString(inBuffer);
}
public int WriteString(string outString)
{
byte[] outBuffer = streamEncoding.GetBytes(outString);
int len = outBuffer.Length;
if (len > UInt16.MaxValue)
{
len = (int)UInt16.MaxValue;
}
ioStream.WriteByte((byte)(len / 256));
ioStream.WriteByte((byte)(len & 255));
ioStream.Write(outBuffer, 0, len);
ioStream.Flush();
return outBuffer.Length + 2;
}
}
Imports System.Diagnostics
Imports System.IO
Imports System.IO.Pipes
Imports System.Security.Principal
Imports System.Text
Imports System.Threading
Public Class PipeClient
Private Shared numClients As Integer = 4
Public Shared Sub Main(args() As String)
If args.Length > 0 Then
If args(0) = "spawnclient" Then
Dim pipeClient As New NamedPipeClientStream( _
".", "testpipe", _
PipeDirection.InOut, PipeOptions.None, _
TokenImpersonationLevel.Impersonation)
Console.WriteLine("Connecting to server..." + vbCrLf)
pipeClient.Connect()
Dim ss As New StreamString(pipeClient)
' Validate the server's signature string.
If ss.ReadString() = "I am the one true server!" Then
' The client security token is sent with the first write.
' Send the name of the file whose contents are returned
' by the server.
ss.WriteString("c:\textfile.txt")
' Print the file to the screen.
Console.Write(ss.ReadString())
Else
Console.WriteLine("Server could not be verified.")
End If
pipeClient.Close()
' Give the client process some time to display results before exiting.
Thread.Sleep(4000)
End If
Else
Console.WriteLine(vbCrLf + "*** Named pipe client stream with impersonation example ***" + vbCrLf)
StartClients()
End If
End Sub
' Helper function to create pipe client processes
Private Shared Sub StartClients()
Dim currentProcessName As String = Environment.CommandLine
Dim plist(numClients - 1) As Process
Console.WriteLine("Spawning client processes..." + vbCrLf)
If currentProcessName.Contains(Environment.CurrentDirectory) Then
currentProcessName = currentProcessName.Replace(Environment.CurrentDirectory, String.Empty)
End If
' Remove extra characters when launched from Visual Studio.
currentProcessName = currentProcessName.Replace("\", String.Empty)
currentProcessName = currentProcessName.Replace("""", String.Empty)
' Change extension for .NET Core "dotnet run" returns the DLL, not the host exe.
currentProcessName = Path.ChangeExtension(currentProcessName, ".exe")
Dim i As Integer
For i = 0 To numClients - 1
' Start 'this' program but spawn a named pipe client.
plist(i) = Process.Start(currentProcessName, "spawnclient")
Next
While i > 0
For j As Integer = 0 To numClients - 1
If plist(j) IsNot Nothing Then
If plist(j).HasExited Then
Console.WriteLine($"Client process[{plist(j).Id}] has exited.")
plist(j) = Nothing
i -= 1 ' decrement the process watch count
Else
Thread.Sleep(250)
End If
End If
Next
End While
Console.WriteLine(vbCrLf + "Client processes finished, exiting.")
End Sub
End Class
' Defines the data protocol for reading and writing strings on our stream
Public Class StreamString
Private ioStream As Stream
Private streamEncoding As UnicodeEncoding
Public Sub New(ioStream As Stream)
Me.ioStream = ioStream
streamEncoding = New UnicodeEncoding(False, False)
End Sub
Public Function ReadString() As String
Dim len As Integer = 0
len = CType(ioStream.ReadByte(), Integer) * 256
len += CType(ioStream.ReadByte(), Integer)
Dim inBuffer As Array = Array.CreateInstance(GetType(Byte), len)
ioStream.Read(inBuffer, 0, len)
Return streamEncoding.GetString(CType(inBuffer, Byte()))
End Function
Public Function WriteString(outString As String) As Integer
Dim outBuffer As Byte() = streamEncoding.GetBytes(outString)
Dim len As Integer = outBuffer.Length
If len > UInt16.MaxValue Then
len = CType(UInt16.MaxValue, Integer)
End If
ioStream.WriteByte(CType(len \ 256, Byte))
ioStream.WriteByte(CType(len And 255, Byte))
ioStream.Write(outBuffer, 0, outBuffer.Length)
ioStream.Flush()
Return outBuffer.Length + 2
End Function
End Class
可靠的编程
此示例中的客户端和服务器进程旨在在同一台计算机上运行，因此提供给 NamedPipeClientStream 对象的服务器名称为 "."。 如果客户端和服务器进程位于单独的计算机上， "." 则会替换为运行服务器进程的计算机的网络名称。
