How to Send SOAP call using MSXML (replace STK)

I know... This is a simple thing, but there is no documentation on it so here it is:

UPDATE: You can now use Windows Webservica API (WWSAPI) to create native code WebService calls!

The SoapToolkit (STK) is out of support.  So what if you need to make a SOAP call in VB 6 or scripting?  Realizing that SOAP calls to web service are just a POST with some XML, you should be able to do this easily.  You can get the format for this POST from a network sniffer such as Network Monitor (available from Microsoft) or from the WSDL of service definition.

Here is a simple definition of a web service that returns the length of a string:

GetStringLength

 

Test

The test form is only available for requests from the local machine.

SOAP 1.1

The following is a sample SOAP 1.1 request and response. The placeholders shown need to be replaced with actual values.

 POST /HelloWS/service.asmx HTTP/1.1
Host: jsandersvm2003
Content-Type: text/xml; charset=utf-8
Content-Length: length
SOAPAction: "http://tempuri.org/GetStringLength"

<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
  <soap:Body>
    <GetStringLength xmlns="http://tempuri.org/">
      <theString>string</theString>
    </GetStringLength>
  </soap:Body>
</soap:Envelope>
 HTTP/1.1 200 OK
Content-Type: text/xml; charset=utf-8
Content-Length: length

<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
  <soap:Body>
    <GetStringLengthResponse xmlns="http://tempuri.org/">
      <GetStringLengthResult>int</GetStringLengthResult>
    </GetStringLengthResponse>
  </soap:Body>
</soap:Envelope>

Here is one way to make this call in a simple VB form application. Reference MSXML3.0 in your project (beware of lines wrapping in your browser if you are a cut and past programmer).

 

 

 

Sub

 

Command2_Click()
    'How to send this using MSXML
    'POST /HelloWS/service.asmx HTTP/1.1
    'Host: jsandersvm2003
    'Content-Type: text/xml; charset=utf-8
    'Content -length: <<length>>

    'SOAPAction: "http://tempuri.org/GetStringLength"

 

    '<?xml version="1.0" encoding="utf-8"?>
    '<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
    ' <soap:Body>
    ' <GetStringLength xmlns="http://tempuri.org/">
    ' <theString><<string>></theString>
    ' </GetStringLength>
    ' </soap:Body>
   

'</soap:Envelope>

 

    Dim myXML As New

XMLHTTP30

 

    ' False means Synchronously
    myXML.open("POST", "http://jsandersvm2003/HelloWS/service.asmx", False)
myXML.setRequestHeader("Content-Type", "text/xml; charset=utf-8")
myXML.setRequestHeader("SOAPAction:", http://tempuri.org/GetStringLength)

' NOTE: You could do this... very brute force way to send it.
    'Dim theTxt As String
    'theTxt = "<?xml version=" & Chr(34) & "1.0" & Chr(34) & " encoding=" & Chr(34) & "utf-8" & Chr(34) & "?><soap:Envelope xmlns:xsi=" & Chr(34) & "http://www.w3.org/2001/XMLSchema-instance" & Chr(34) & " xmlns:xsd=" & Chr(34) & "http://www.w3.org/2001/XMLSchema" & Chr(34) & " xmlns:soap=" & Chr(34) & "http://schemas.xmlsoap.org/soap/envelope/" & Chr(34) & "><soap:Body><GetStringLength xmlns=" & Chr(34) & "http://tempuri.org/" & Chr(34) & "><theString xmlns=" & Chr(34) & "http://tempuri.org/" & Chr(34) & ">string</theString></GetStringLength></soap:Body></soap:Envelope>"

 

 

 

 

 

    'myXML.send theTxt
   

' NOTE: This allows you to leverage the XML DOM

 

    Dim node
Dim xmlSrcDoc As New MSXML2.DOMDocument30
xmlSrcDoc.async = False
    xmlSrcDoc.validateOnParse = False
xmlSrcDoc.resolveExternals = False
xmlSrcDoc.preserveWhiteSpace = True
' caveat for the createProcessingInstruction. the encoding string will be missing from the XML instruction line.
    ' so you could skip the createProcessingInstruction code, instead prepend the string to the XML you generate for the rest of the body ala
'

"myXML.send "<?xml version=" & Chr(34) & "1.0" & Chr(34) & " encoding=" & Chr(34) & "utf-8" & Chr(34) & " ?> " & xmlSrcDoc.xml

 

' most servers will not care about that because the HTTP header already specifies the encoding
    ' Create a processing instruction targeted for xml.
node = xmlSrcDoc.createProcessingInstruction("xml", "version='1.0'")
' issue: cannot do this: node.setAttribute "encoding", "utf-8"
    xmlSrcDoc.appendChild(node)
node = Nothing
' Create the Soap Envelope
    Dim soapEnvelope As IXMLDOMElement
soapEnvelope = xmlSrcDoc.createElement("soap:Envelope")
' Create the attributes for it
    soapEnvelope.setAttribute("xmlns:soap", "http://schemas.xmlsoap.org/soap/envelope/")
soapEnvelope.setAttribute("xmlns:xsi", "http://www.w3.org/2001/XMLSchema-instance")
soapEnvelope.setAttribute("xmlns:xsd", "http://www.w3.org/2001/XMLSchema")
xmlSrcDoc.appendChild(soapEnvelope)
' Create the Soap Body
    Dim soapBody As IXMLDOMElement
soapBody = xmlSrcDoc.createElement("soap:Body")
soapEnvelope.appendChild(soapBody)
' Create the node for the call we are making
    Dim soapCall As IXMLDOMElement
soapCall = xmlSrcDoc.createElement("GetStringLength")
soapCall.setAttribute("xmlns", "http://tempuri.org/")
soapBody.appendChild(soapCall)
' finally add the argument(s)
    Dim soapArgs As Object
soapArgs = xmlSrcDoc.createElement("theString")
soapArgs.Text = "Jeff is cool"
soapCall.appendChild(soapArgs)
' let it go!
    myXML.send(xmlSrcDoc.xml)
' myXML.send "<?xml version=" & Chr(34) & "1.0" & Chr(34) & " encoding=" & Chr(34) & "utf-8" & Chr(34) & " ?> " & xmlSrcDoc.xml
    Dim xmlDoc As MSXML2.DOMDocument30
xmlDoc = myXML.responseXML
' This query will depend on what you expect back from the SOAP call
   

MsgBox(xmlDoc.Text)

 

    ' or this if you want to traverse the XML DOM
    'Dim oNode As Object
    'Set oNode = xmlDoc.documentElement.selectSingleNode("//HelloWorldResult")
    'If oNode Is Nothing Then
    ' MsgBox "Requested information not found."
    'Else
    ' MsgBox oNode.Text
   

'End If

End

 

Sub