VBA WinHttpWebSocketSend Error 12030: Troubleshooting and Solutions

This article will guide you through troubleshooting error 12030 encountered when using WinHttpWebSocketSend in VBA. This error typically signals that the websocket connection has been closed or is in the process of closing. Let's explore common causes and potential solutions.

Understanding Error 12030

Error code 12030 ('ERROR_CONNECTION_ABORTED') suggests that the websocket connection is no longer active. This can happen due to various reasons, including:

Network Issues: Intermittent network connectivity problems can disrupt the websocket communication.
Server-Side Closure: The server may have closed the connection intentionally (e.g., due to inactivity or an error).
Client-Side Closure: Your code may have unintentionally closed the connection.
Timeout: If the server takes too long to respond, the connection might be timed out by either your code or the network.

Code Walkthrough and Debugging

Let's examine your provided VBA code to pinpoint potential areas for improvement:

Dim message(1) As String
message(0) = '{\"session_hash\": \"f4bqo5ku927\", \"fn_index\": 3}'
Dim cdwMessageLength As Long
cdwMessageLength = 2 * Len(message(0))                     ' two bytes per character

' Send and receive data on the websocket protocol.
dwError = WinHttpWebSocketSend(hWebSocketHandle, _
        WINHTTP_WEB_SOCKET_UTF8_MESSAGE_BUFFER_TYPE, StrPtr(message(0)), cdwMessageLength)
If (dwError <> ERROR_SUCCESS) Then
    dwError = GetLastError
    GoTo quit
End If
Debug.Print "Sent message to the server: " & message(0)
ReDim rgbBuffer(1023) As Byte
Dim dwBufferLength As Long

' get correct value in case of change to buffer size
dwBufferLength = (UBound(rgbBuffer) - LBound(rgbBuffer) + 1)

Dim pbCurrentBufferPointer As Long
pbCurrentBufferPointer = VarPtr(rgbBuffer(0))
Dim dwBytesTransferred As Long
dwBytesTransferred = 0
Dim eBufferType As Long
eBufferType = 0
Dim dwCloseReasonLength As Long
dwCloseReasonLength = 0
Dim usStatus As Integer
usStatus = 0


' loop if we get a message fragment packet
' added a failsafe counter to original code - probably unnecessary
Dim MessageComplete As Boolean, count As Long
MessageComplete = False
count = 0
Do Until (MessageComplete Or (count > 40))
    
    If (dwBufferLength = 0) Then
        dwError = ERROR_NOT_ENOUGH_MEMORY
        GoTo quit
    End If
    count = count + 1
    Debug.Print "Check receive buffer: " & count
    ' receive - will hang if no server response
    dwError = WinHttpWebSocketReceive(hWebSocketHandle, rgbBuffer(0), dwBufferLength, dwBytesTransferred, eBufferType)
    If (dwError <> ERROR_SUCCESS) Then
        dwError = GetLastError
        GoTo quit
    End If
    ' If we receive just part of the message restart the receive operation.
    pbCurrentBufferPointer = pbCurrentBufferPointer + dwBytesTransferred
    dwBufferLength = dwBufferLength - dwBytesTransferred
    If Not (eBufferType = WINHTTP_WEB_SOCKET_BINARY_FRAGMENT_BUFFER_TYPE) Then
        MessageComplete = True
    End If
' Application.Wait Now + TimeValue("00:00:05")
Loop

''    ' Expected server to just echo single binary message - complain if different
'''    If (eBufferType <> WINHTTP_WEB_SOCKET_BINARY_MESSAGE_BUFFER_TYPE) Then
'''        Debug.Print "Unexpected buffer type"
'''        dwError = 87                                           ' ERROR_INVALID_PARAMETER
'''        GoTo quit
'''    End If

' convert buffer into string (crudely, just ignore zeros)
' Dim j As Long, strBuffer As String
strBuffer = ""
For j = LBound(rgbBuffer) To UBound(rgbBuffer)
If rgbBuffer(j) <> 0 Then
strBuffer = strBuffer & Chr(rgbBuffer(j))
End If
Next
Debug.Print "Received message from the server: " & strBuffer

message(1) = '{\"fn_index\": 3, \"data\": [\"dog wearing a hat\", \"\", 9], \"session_hash\": \"f4bqo5ku927\"}'

cdwMessageLength = 2 * Len(message(1))                     ' two bytes per character

' Send and receive data on the websocket protocol.
dwError = WinHttpWebSocketSend(hWebSocketHandle, _
        WINHTTP_WEB_SOCKET_UTF8_MESSAGE_BUFFER_TYPE, StrPtr(message(1)), cdwMessageLength) 为什么第二次WinHttpWebSocketSend 是12030 第一次是 零内容：错误代码12030表示连接已经关闭或正在关闭。这可能是由于网络问题或服务器端关闭连接引起的。在第一次发送后，可能需要等待服务器响应或等待一段时间以确保服务器已经处理完前一个请求并准备好接收下一个请求。您可以尝试增加等待时间或与服务器管理员联系以获取更多信息。

Troubleshooting Steps

Check for Network Connectivity: Verify that your network connection is stable and reliable. Try connecting to other websites to rule out general internet issues.
Server Availability: Ensure that the server hosting the websocket service is online and functional. Contact the server administrator if necessary.
Server-Side Logging: Review server logs for any errors or warnings that might indicate connection closure.
Handle Server Responses: Implement proper handling of server responses within your VBA code. If the server closes the connection after a specific action, your code should gracefully handle this scenario.
Timeout Management: Implement timeouts in your WinHttpWebSocketSend and WinHttpWebSocketReceive calls. This prevents your code from hanging indefinitely if the server doesn't respond.
Error Handling: Robust error handling is crucial. Instead of using GoTo quit, handle errors gracefully and provide informative messages.
Debug Output: Use Debug.Print statements to output detailed information about the state of your connection, message content, and error codes. This will help you pinpoint the exact point where the error occurs.

Best Practices

Use a library: Consider using a dedicated websocket library for VBA to simplify communication and error handling.
Test Thoroughly: Test your code with different network conditions and server scenarios.
Logging: Log all relevant events, including connection establishment, message send/receive, and errors. This is invaluable for debugging and troubleshooting.

Example Code with Error Handling

' ... your code...

dwError = WinHttpWebSocketSend(hWebSocketHandle, _
        WINHTTP_WEB_SOCKET_UTF8_MESSAGE_BUFFER_TYPE, StrPtr(message(1)), cdwMessageLength)

If (dwError <> ERROR_SUCCESS) Then
    ' Handle error 12030
    If (dwError = ERROR_CONNECTION_ABORTED) Then
        Debug.Print "Connection closed: ERROR_CONNECTION_ABORTED"
        ' Handle connection closure (e.g., reconnect or notify user)
    Else
        dwError = GetLastError
        Debug.Print "WinHttpWebSocketSend Error: " & dwError
        ' Handle other potential errors
    End If
    GoTo quit
End If

' ... your code...

Key Points:

Error 12030 indicates a closed websocket connection, often due to network issues or server actions.
Implementing robust error handling, timeout management, and debugging tools will greatly enhance the reliability and maintainability of your code.
If you suspect server-side issues, consult with the server administrator.

Remember: Thorough testing and debugging are essential for ensuring reliable communication over websockets in your VBA applications.

VBA WinHttpWebSocketSend Error 12030: Troubleshooting and Solutions