作法:使用具名管道進行網路處理序間通訊
命名管道提供管道伺服器與一或多個管道客戶端之間的進程間通訊。 它們提供的功能比匿名管道更多,可在本機計算機上提供進程間通訊。 命名管道支援透過網路及多個伺服器實例的完整雙工通訊、基於訊息的通訊以及用戶端模仿,這使得連線程序能在遠端伺服器上使用它們自己的許可權集。
這很重要
Linux 上的 .NET 會使用 Unix 網域套接字 (UDS) 來實作這些 API。
若要實作名稱管道,請使用 NamedPipeServerStream 和 NamedPipeClientStream 類別。
範例 1
下列範例示範如何使用 類別建立命名管道 NamedPipeServerStream 。 在此範例中,伺服器進程會建立四個線程。 每個線程都可以接受客戶端連線。 用戶端程式然後會向伺服器提供檔名。 如果用戶端有足夠的許可權,伺服器進程會開啟檔案,並將其內容傳回用戶端。
#using <System.Core.dll>
using namespace System;
using namespace System::IO;
using namespace System::IO::Pipes;
using namespace System::Text;
using namespace System::Threading;
// Defines the data protocol for reading and writing strings on our stream
public ref class StreamString
{
private:
Stream^ ioStream;
UnicodeEncoding^ streamEncoding;
public:
StreamString(Stream^ ioStream)
{
this->ioStream = ioStream;
streamEncoding = gcnew UnicodeEncoding();
}
String^ ReadString()
{
int len;
len = ioStream->ReadByte() * 256;
len += ioStream->ReadByte();
array<Byte>^ inBuffer = gcnew array<Byte>(len);
ioStream->Read(inBuffer, 0, len);
return streamEncoding->GetString(inBuffer);
}
int WriteString(String^ outString)
{
array<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 ref class ReadFileToStream
{
private:
String^ fn;
StreamString ^ss;
public:
ReadFileToStream(StreamString^ str, String^ filename)
{
fn = filename;
ss = str;
}
void Start()
{
String^ contents = File::ReadAllText(fn);
ss->WriteString(contents);
}
};
public ref class PipeServer
{
private:
static int numThreads = 4;
public:
static void Main()
{
int i;
array<Thread^>^ servers = gcnew array<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] = gcnew Thread(gcnew ThreadStart(&ServerThread));
servers[i]->Start();
}
Thread::Sleep(250);
while (i > 0)
{
for (int j = 0; j < numThreads; j++)
{
if (servers[j] != nullptr)
{
if (servers[j]->Join(250))
{
Console::WriteLine("Server thread[{0}] finished.", servers[j]->ManagedThreadId);
servers[j] = nullptr;
i--; // decrement the thread watch count
}
}
}
}
Console::WriteLine("\nServer threads exhausted, exiting.");
}
private:
static void ServerThread()
{
NamedPipeServerStream^ pipeServer =
gcnew NamedPipeServerStream("testpipe", PipeDirection::InOut, numThreads);
int threadId = 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.
StreamString^ ss = gcnew 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 = gcnew 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(gcnew PipeStreamImpersonationWorker(fileReader, &ReadFileToStream::Start));
}
// Catch the IOException that is raised if the pipe is broken
// or disconnected.
catch (IOException^ e)
{
Console::WriteLine("ERROR: {0}", e->Message);
}
pipeServer->Close();
}
};
int main()
{
PipeServer::Main();
}
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
範例 2
下列範例顯示使用 類別的 NamedPipeClientStream 客戶端進程。 用戶端會連線到伺服器進程,並將檔名傳送至伺服器。 此範例會使用模擬,因此執行用戶端應用程式的身分必須具有存取檔案的權限。 然後伺服器會將檔案的內容傳回用戶端。 然後,檔案內容會顯示至主控台。
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
健全的程式設計
這個範例中的用戶端和伺服器進程是要在同一部電腦上執行,因此提供給 NamedPipeClientStream 物件的伺服器名稱是 "."
。 如果客戶端和伺服器進程位於不同的電腦上, "."
則會取代為執行伺服器進程之計算機的網路名稱。