我正在创建一个需要通过TCP与第三方软件连接的Web应用程序。
使用以下命令通过tcp将数据从Nodejs发送到软件没有问题：
var client = net.connect({host: [IP], port: [PORT]}, function() { //'connect' listener;
client.write('[DATA TO SEND]');
});
第三方软件返回对发送数据的响应。问题是该软件没有发送特定事件，因此不会工作：
//THIS WILL NOT WORK, NO EVENT IS SENT FROM THIRD-PARTY SOFTWARE:
client.on('data', function(data) {
console.log(data.toString());
client.end();
});
是否可以在没有事件的情况下从TCP请求获取响应？ 任何建议将不胜感激！ TIA！
这是我连接第三方软件VIA VB的方式：
'Connects to SOFTWARE
Public Function Connect() As Boolean
mTcpClient = New TcpClient
Try
mTcpClient.Client.Connect(Host, Port)
' RaiseEvent tcpConnectionStatus(Host, Port, True)
dashboardAlerts.updateParameterStatus("engineStatus", "OK")
Return True
Catch ex As Exception
RaiseEvent connectionError()
dashboardAlerts.updateParameterStatus("engineStatus", "ERROR")
Return False
End Try
End Function
Public Sub Disconnect()
mTcpClient.Client.Disconnect(True)
RaiseEvent tcpConnectionStatus(Host, Port, False)
End Sub
'Sends command to engine via TCP
Public Sub Send(ByVal Command As String)
If Not mTcpClient.Client.Connected Then
Exit Sub
End If
Command &= Chr(0)
Dim mBytes() As Byte
mBytes = System.Text.Encoding.UTF8.GetBytes(vizCommand)
Try
mTcpClient.Client.Send(mBytes, mBytes.Length, SocketFlags.None)
dashboardAlerts.updateParameterStatus("Status", "OK")
Catch ex As Exception
dashboardAlerts.updateParameterStatus("Status", "ERROR")
'error
End Try
End Sub
'Reads data from TCP connection buffer
Public Function Receive() As String
Dim mBytesToRead As Integer = mTcpClient.Available
If mBytesToRead = 0 Then
Return "Nothing to read"
End If
Dim mBytes(mBytesToRead) As Byte
Try
mTcpClient.Client.Receive(mBytes, mBytesToRead, SocketFlags.None)
Catch ex As Exception
'Error
End Try
Return System.Text.Encoding.UTF8.GetString(mBytes)
End Function
'------------------ LISTENER -----------------------------------------
'Starts software listener
Public Function listenToSoftware() As Boolean
If Not isListening Then
listenerBackgroundWorker = New BackgroundWorker
listenerBackgroundWorker.WorkerSupportsCancellation = True
' RaiseEvent tcpConnectionStatus(Host, Port, True)
listenerBackgroundWorker.RunWorkerAsync()
End If
Return True
End Function
'Starts listening when backgroundworker starts
Sub startListener() Handles listenerBackgroundWorker.DoWork
Dim myTcpListener As TcpListener
Try
myTcpListener = New TcpListener(System.Net.IPAddress.Parse(Host), Port)
isListening = True
Console.WriteLine("Waiting for connection...")
Catch exp As Exception
dashboardAlerts.updateParameterStatus("engineStatus", "ERROR")
' box(exp.Message & ":" & exp.StackTrace)
serviceLog.addToLog("Error creating engine listener: " & exp.Message, serviceLog.logLevelOptions.OnlylogFile)
Exit Sub
End Try
'Start listening
myTcpListener.Start()
'Blocking - till connection is made
Dim isLoop As Boolean = True
Dim myCompleteMessage As StringBuilder = New StringBuilder()
'when connection is made, reads data
While (isLoop)
Try
Dim networkStream As NetworkStream
Dim tcpClient As TcpClient
If myTcpListener.Pending Then
'Accept the pending client connection and return a TcpClient initialized for communication.
tcpClient = myTcpListener.AcceptTcpClient()
'Get the stream
networkStream = tcpClient.GetStream()
' Read the stream
If networkStream.CanRead Then
Dim myReadBuffer(1024) As Byte
Dim numberOfBytesRead As Integer = 0
' Incoming message may be larger than the buffer size.
Do
numberOfBytesRead = networkStream.Read(myReadBuffer, 0, myReadBuffer.Length)
myCompleteMessage.AppendFormat("{0}", Encoding.ASCII.GetString(myReadBuffer, 0, numberOfBytesRead))
Loop While networkStream.DataAvailable
isLoop = False
Else
Console.WriteLine("Sorry. You cannot read from this NetworkStream.")
End If
networkStream.Close()
tcpClient.Close()
End If
Catch ex As Exception
serviceLog.addToLog("Error in TCP listener: " & ex.Message, serviceLog.logLevelOptions.OnlylogFile)
End Try
End While
myTcpListener.Stop()
CancelListener()
isListening = False
'Checks if there is Null (chr(0)) in the end, and removes it
Dim vizMessage As String = myCompleteMessage.ToString
If vizMessage.Contains(Chr(0)) Then
vizMessage = vizMessage.Remove(vizMessage.IndexOf(Chr(0)))
End If
dashboardAlerts.updateParameterStatus("engineStatus", "OK")
RaiseEvent dataReceived(vizMessage)
End Sub
'When listen is complete (recieved answer)
Private Sub searchBackgroundWorker_RunWorkerCompleted(ByVal sender As Object, ByVal e As RunWorkerCompletedEventArgs) _
Handles listenerBackgroundWorker.RunWorkerCompleted
listenerBackgroundWorker.Dispose()
End Sub
'When listen is disposed(canceled)
Private Sub searchBackgroundWorker_RunWorkerDisposed() Handles listenerBackgroundWorker.Disposed
'RaiseEvent tcpConnectionStatus(Host, Port, False)
End Sub
'Cancels current listen thread
Sub CancelListener()
If isListening Then
listenerBackgroundWorker.CancelAsync()
listenerBackgroundWorker.Dispose()
Console.WriteLine(vbLf & "listener Cancelled")
End If
' RaiseEvent reportProductionComplete("Canceled")
End Sub
#Region "Thread and events"
'When check engines' timer ticks
Private Sub timerCheckengines_Tick(sender As Object, e As EventArgs) Handles timerCheckConnection.Elapsed
timerCheckConnection.Stop() 'Stops timer while check engines
startConnectionCheck() 'Invokes thread
End Sub
'Starts the actual thread
Private Sub startConnectionCheck()
connectionBackgroundWorker = New BackgroundWorker
Me.connectionBackgroundWorker.RunWorkerAsync() 'Starts engines check thread
End Sub
答案 0 :(得分：1)
data事件是本地节点事件。它会在数据到达套接字时发出，而不是远程端以某种方式显式触发的内容。 FWIW除了收听data事件外，您还可以使用client.read(..)和readable事件从套接字中提取数据。