Как отправить запрос и получить ответ, используя system.io.pipes
Я пытаюсь написать клиент и сервер, которые общаются через именованные каналы. Мне нужно, чтобы клиент мог отправить запрос на сервер и чтобы сервер отправил ответ. Все примеры в Интернете для System.IO.pipes отправляют одну строку клиенту или одну строку серверу. Я нашел несколько примеров того, как это сделать со старыми каналами Win32. Но я не могу это использовать.
Вот что у меня так далеко. Я знаю, что это много кода. Но я думаю, что проблема может заключаться только в одном из конструкторов потоковых потоков.
Код клиента
Private Sub cmdSend_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdSend.Click
Dim strMsg As String = ""
Dim strRequest As String = "Send Key"
Dim strErrMsg As String = ""
PrintText("Creating new pipe client")
'pipeStream = New NamedPipeClientStream(strPipeName)
'pipeStream = New NamedPipeClientStream(strPipeName, PipeDirection.InOut, 1, PipeTransmissionMode.Message, PipeOptions.None)
pipeStream = New NamedPipeClientStream(strServerName, strPipeName, PipeDirection.InOut, PipeOptions.None, Security.Principal.TokenImpersonationLevel.None)
PrintText("Connecting to server")
pipeStream.Connect()
pipeStream.ReadMode = PipeTransmissionMode.Message
PrintText("Sending request")
'Send Request
If SendPipeMessage(pipeStream, strRequest, strErrMsg) Then
Else
PrintText(strErrMsg)
End If
PrintText("Receiving response")
'Process Response
If ReadPipeMessage(pipeStream, strMsg, strErrMsg) Then
PrintText(strMsg)
Else
PrintText(strErrMsg)
End If
pipeStream.Dispose()
pipeStream = Nothing
End Sub
Private Function SendPipeMessage(ByRef pipeStream As NamedPipeClientStream, ByVal strMsg As String, ByRef strErrMsg As String) As Boolean
Dim blnRetVal As Boolean = True
Dim bytMessage() As Byte = Nothing
Dim encoding As UTF8Encoding = Nothing
Try
encoding = New UTF8Encoding
bytMessage = encoding.GetBytes(strMsg)
pipeStream.Write(bytMessage, 0, bytMessage.Length)
Catch ex As Exception
blnRetVal = False
strErrMsg = ex.ToString
End Try
Return blnRetVal
End Function
Private Function ReadPipeMessage(ByRef pipeStream As NamedPipeClientStream, ByRef strPipeText As String, ByRef strErrMsg As String) As Boolean
Dim blnRetVal As Boolean = True
Dim strTextChunck As String = ""
Dim intNumBytes As Integer = 0
Dim intNumChars As Integer = 0
Dim bytMessage(10) As Byte
Dim chars(10) As Char
Dim decoder As Decoder = Nothing
Try
decoder = Encoding.UTF8.GetDecoder
strPipeText = ""
Do
strTextChunck = ""
Do
intNumBytes = pipeStream.Read(bytMessage, 0, bytMessage.Length)
intNumChars = decoder.GetChars(bytMessage, 0, intNumBytes, chars, 0)
strTextChunck = strTextChunck & New String(chars, 0, intNumChars)
Loop While Not pipeStream.IsMessageComplete
strPipeText = strPipeText & strTextChunck
Loop While intNumBytes <> 0
Catch ex As Exception
blnRetVal = False
strErrMsg = ex.ToString
End Try
Return blnRetVal
End Function
Код сервера
Private Sub cmdListen_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdListen.Click
bw.RunWorkerAsync()
End Sub
Private Sub bw_DoWork(ByVal sender As System.Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles bw.DoWork
Dim strRequest As String = ""
Dim strErrMsg As String = ""
bw.ReportProgress(0, "Create new pipe server stream")
pipeStream = New NamedPipeServerStream(strPipeName, PipeDirection.InOut, 1, PipeTransmissionMode.Message, PipeOptions.None)
'Wait for connection
bw.ReportProgress(0, "Listening for connection")
pipeStream.WaitForConnection()
bw.ReportProgress(0, "Receiving request")
'Receive Request
If ReadPipeMessage(pipeStream, strRequest, strErrMsg) Then
bw.ReportProgress(0, "Request : " & strRequest)
Else
bw.ReportProgress(0, strErrMsg)
End If
'Get response
strResponse = GetResponse(strRequest)
bw.ReportProgress(0, "Sending response")
'Send Response
If SendPipeMessage(pipeStream, strResponse, strErrMsg) Then
bw.ReportProgress(0, "Sent response")
Else
bw.ReportProgress(0, strErrMsg)
End If
bw.ReportProgress(0, "Done!")
pipeStream.Disconnect()
pipeStream.Dispose()
pipeStream = Nothing
End Sub
Private Sub bw_ProgressChanged(ByVal sender As Object, ByVal e As System.ComponentModel.ProgressChangedEventArgs) Handles bw.ProgressChanged
PrintText(e.UserState)
End Sub
Private Sub bw_RunWorkerCompleted(ByVal sender As Object, ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles bw.RunWorkerCompleted
PrintText(e.Result)
End Sub
Private Function SendPipeMessage(ByRef pipeStream As NamedPipeServerStream, ByVal strMsg As String, ByRef strErrMsg As String) As Boolean
Dim blnRetVal As Boolean = True
Dim bytMessage() As Byte = Nothing
Dim encoding As UTF8Encoding = Nothing
Try
encoding = New UTF8Encoding
bytMessage = encoding.GetBytes(strMsg)
pipeStream.Write(bytMessage, 0, bytMessage.Length)
Catch ex As Exception
blnRetVal = False
strErrMsg = ex.ToString
End Try
Return blnRetVal
End Function
Private Function ReadPipeMessage(ByRef pipeStream As NamedPipeServerStream, ByRef strPipeText As String, ByRef strErrMsg As String) As Boolean
Dim blnRetVal As Boolean = True
Dim strTextChunck As String = ""
Dim intNumBytes As Integer = 0
Dim intNumChars As Integer = 0
Dim bytMessage(10) As Byte
Dim chars(10) As Char
Dim decoder As Decoder = Nothing
Try
decoder = Encoding.UTF8.GetDecoder
strPipeText = ""
Do
strTextChunck = ""
Do
intNumBytes = pipeStream.Read(bytMessage, 0, bytMessage.Length)
intNumChars = decoder.GetChars(bytMessage, 0, intNumBytes, chars, 0)
strTextChunck = strTextChunck & New String(chars, 0, intNumChars)
Loop While Not pipeStream.IsMessageComplete
strPipeText = strPipeText & strTextChunck
Loop While intNumBytes <> 0
Catch ex As Exception
blnRetVal = False
strErrMsg = ex.ToString
End Try
Return blnRetVal
End Function
Когда я запускаю клиент, он висит на ReadPipMessage(), а сервер - на ReceivingRequest(). Если я убью клиента, сервер прочитает запрос, отправленный клиентом. Но он бомбит при отправке ответа, потому что клиент больше не работает.
Разве сервер не может отправлять и получать сообщения в том же соединении? Я думал, что это то, что имел в виду PipeDirection.InOut.
Спасибо,
Майк
1 ответ
Вы можете посмотреть на привязку именованных каналов для WCF. Есть много хороших примеров того, как его использовать, например: http://www.jmedved.com/2010/03/named-pipes-in-wcf/