【转载】VBA–验证是否存在URL

时　间:2023-03-28 10:19:00
作　者:金宇   ID：43  城市：江阴
摘　要:VBA–验证是否存在URL。
正　文:

      当我们要处理一个文件时，通常最好先进行测试以确保文件存在，如果我们需要从某个网站下载文件，那么需要先验证这个网址URL是否存在，那么可以通过下列的函数来进行校验。

      可以将下列的代码放到新建的模块中，然后可以在窗体的事件中进行调用，例如： WinHTTP_URLExist("http://www.accessoft.com")

Function WinHTTP_URLExist(ByVal sURL As String) As Boolean
    On Error GoTo Error_Handler
    #Const WinHTTP_EarlyBind = False   'True => Early Binding / False => Late Binding
    #If WinHTTP_EarlyBind = True Then
        Dim oWinHttp          As WinHttp.WinHttpRequest

        Set oWinHttp = New WinHttp.WinHttpRequest
    #Else
        Dim oWinHttp          As Object
        Const WinHttpRequestOption_UserAgentString = 0
        Const WinHttpRequestOption_EnableRedirects = 6

        Set oWinHttp = CreateObject("WinHttp.WinHttpRequest.5.1")
    #End If
    Dim lStatusCode           As Integer

    With oWinHttp
        .Option(WinHttpRequestOption_EnableRedirects) = False
        .Option(WinHttpRequestOption_UserAgentString) = "curl"
        .SetTimeouts 3000, 5000, 3000, 5000
        .Open "HEAD", sURL, False
        .Send
        lStatusCode = .Status
    End With
    WinHTTP_URLExist = (lStatusCode = 200)

Error_Handler_Exit:
    On Error Resume Next
    Set oWinHttp = Nothing
    Exit Function

Error_Handler:
    '-2147012889   The server name or address could not be resolved
    '-2147012894   The operation timed out
    If Err.Number <> -2147012889 And Err.Number <> -2147012894 Then
        MsgBox "The following error has occurred" & vbCrLf & vbCrLf & _
               "Error Source: WinHTTP_URLExist" & vbCrLf & _
               "Error Number: " & Err.Number & vbCrLf & _
               "Error Description: " & Err.Description & _
               Switch(Erl = 0, "", Erl <> 0, vbCrLf & "Line No: " & Erl) _
               , vbOKOnly + vbCritical, "An Error has Occurred!"
    End If
    Resume Error_Handler_Exit
End Function