How to call web service using vbscript (synchronous) ?

Question

Actually there many examples and I have used one of them. But it works asynchronous, I mean it is not waiting the function that I called to finish.

function ProcessSend() 
    Set oXMLHTTP = CreateObject("MSXML2.XMLHTTP.4.0")
    Set oXMLDoc = CreateObject("MSXML2.DOMDocument")

    oXMLHTTP.onreadystatechange = getRef("HandleStateChange") 

    strEnvelope = "callNo="&callNo&"&exp="&exp

    call oXMLHTTP.open("POST","http://localhost:11883/ServiceCall.asmx/"&posFirm,true)
    call oXMLHTTP.setRequestHeader("Content-Type","application/x-www-form-urlencoded")


    call oXMLHTTP.send(strEnvelope)
end function

Sub HandleStateChange 
    if(oXMLHTTP.readyState = 4) then
     dim szResponse: szResponse = oXMLHTTP.responseText
     call oXMLDoc.loadXML(szResponse)
     if(oXMLDoc.parseError.errorCode <> 0) then
      'call msgbox("ERROR")
      response = oXMLHTTP.responseText&" "&oXMLDoc.parseError.reason
      'call msgbox(oXMLDoc.parseError.reason)
     else
      response = oXMLDoc.getElementsByTagName("string")(0).childNodes(0).text
     end if

    end if
End Sub

I call ProcessSend function in a javascript function. It connects to webservice, and returns the "response" variable. But my javascript function do not wait ProcessSend function result. How can I make it synchronous?

Answer 1

Here you go:

function ProcessSend() 
    Set oXMLHTTP = CreateObject("MSXML2.XMLHTTP.4.0")
    Set oXMLDoc = CreateObject("MSXML2.DOMDocument")

    oXMLHTTP.onreadystatechange = getRef("HandleStateChange") 

    strEnvelope = "callNo="&callNo&"&exp="&exp

    call oXMLHTTP.open("POST","http://localhost:11883/ServiceCall.asmx/"&posFirm,false)'<< changed true to false here.
    call oXMLHTTP.setRequestHeader("Content-Type","application/x-www-form-urlencoded")


    call oXMLHTTP.send(strEnvelope)
end function

Sub HandleStateChange 
    if(oXMLHTTP.readyState = 4) then
        dim szResponse: szResponse = oXMLHTTP.responseText
        call oXMLDoc.loadXML(szResponse)
        if(oXMLDoc.parseError.errorCode <> 0) then
                'call msgbox("ERROR")
                response = oXMLHTTP.responseText&" "&oXMLDoc.parseError.reason
                'call msgbox(oXMLDoc.parseError.reason)
        else
                response = oXMLDoc.getElementsByTagName("string")(0).childNodes(0).text
        end if

    end if
End Sub

Why are you btw doing this in VBScript, if the rest of your code is in JScript? Like this:

function ProcessSend(){ 
    var oXMLHTTP = ActiveXObject("MSXML2.XMLHTTP.4.0") 
    strEnvelope = "callNo=" + callNo + " & exp=" + exp;
    oXMLHTTP.open("POST", "http://localhost:11883/ServiceCall.asmx/" + posFirm, false);
    oXMLHTTP.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
    oXMLHTTP.send(strEnvelope);
    if(oXMLHTTP.readyState == 4){
        if(oXMLHTTP.responseXML.parseError.errorCode != 0){
                response = oXMLHTTP.responseText & " " & oXMLHTTP.responseXML.parseError.reason;
        }else{
                response = oXMLHTTP.responseXML.getElementsByTagName("string")(0).childNodes(0).text;
        }
    }
}

Answer 2

If you're doing synchronous calls, you don't need the callback, and you can shrink the code into this:

function ProcessSend() 
    Set oXMLHTTP = CreateObject("MSXML2.XMLHTTP.4.0")
    Set oXMLDoc = CreateObject("MSXML2.DOMDocument")

    strEnvelope = "callNo=" & callNo & "&exp=" & exp

    call oXMLHTTP.open("POST", "http://localhost:11883/ServiceCall.asmx/"&posFirm, false)
    call oXMLHTTP.setRequestHeader("Content-Type","application/x-www-form-urlencoded")
    call oXMLHTTP.send(strEnvelope)

    dim szResponse: szResponse = oXMLHTTP.responseText
    call oXMLDoc.loadXML(szResponse)

    if(oXMLDoc.parseError.errorCode <> 0) then
        'call msgbox("ERROR")
        response = oXMLHTTP.responseText&" "&oXMLDoc.parseError.reason
        'call msgbox(oXMLDoc.parseError.reason)
    else
        response = oXMLDoc.getElementsByTagName("string")(0).childNodes(0).text
    end if
End Sub