VB using SOAP & XML for web services

Question

I am trying to perform a XML Soap call in a VB application to a web service. I can get this to work using SoapUI and XMLSpy, which leads me to believe that the XML is correct. When I perform the code I get an error 500 Server Internal Error. Which leads me to believe I am missing something in the code and not in the XML. I did try adding a Server Reference, but that didn't seem to help either.

I used this video as a reference: "Visual Basic - WebRequests VB.net Intermediate" My code looks like this:

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

    Dim SoapByte() As Byte
    Dim SoapStr As String = ""
    SoapStr = SoapStr & "<?xml version=""1.0"" encoding=""UTF-8""?>"
    SoapStr = SoapStr & "<soapenv:Envelope xmlns:soapenv=""http://schemas.xmlsoap.org/soap/envelope/"" xmlns:web=""http://webservice.lme.com"">"
    SoapStr = SoapStr & "<soapenv:Header/>"
    SoapStr = SoapStr & "<soapenv:Body>"
    SoapStr = SoapStr & "<web:getCustomerRate>"
    SoapStr = SoapStr & "<web:criIn>"
    SoapStr = SoapStr & "<web:protectFreeze>Y</web:protectFreeze>"
    SoapStr = SoapStr & "<web:accountNumber>226744</web:accountNumber>"
    SoapStr = SoapStr & "<web:callConsgBfrDel>No</web:callConsgBfrDel>"
    SoapStr = SoapStr & "<web:callforAppmnt>No</web:callforAppmnt>"
    SoapStr = SoapStr & "<web:callforCarrierConv>No</web:callforCarrierConv>"
    SoapStr = SoapStr & "<web:COD>N</web:COD>"
    SoapStr = SoapStr & "<web:CODAmount>0</web:CODAmount>"
    SoapStr = SoapStr & "<web:CODPayTerms>0</web:CODPayTerms>"
    SoapStr = SoapStr & "<!--1 or more repetitions:-->"
    SoapStr = SoapStr & "<web:commLines>"
    SoapStr = SoapStr & "<web:commClass>100</web:commClass>"
    SoapStr = SoapStr & "<web:commweight>1000</web:commweight>"
    SoapStr = SoapStr & "</web:commLines>"
    SoapStr = SoapStr & "<web:customerType>S</web:customerType>"
    SoapStr = SoapStr & "<web:destCity>Lake City</web:destCity>"
    SoapStr = SoapStr & "<web:destState>MN</web:destState>"
    SoapStr = SoapStr & "<web:destZip>55041</web:destZip>"
    SoapStr = SoapStr & "<web:fullValueCoverage>No</web:fullValueCoverage>"
    SoapStr = SoapStr & "<web:fvcAmount>0</web:fvcAmount>"
    SoapStr = SoapStr & "<web:hazMat>N</web:hazMat>"
    SoapStr = SoapStr & "<web:insideDel>No</web:insideDel>"
    SoapStr = SoapStr & "<web:insidePckup>No</web:insidePckup>"
    SoapStr = SoapStr & "<web:lftgtReqDel>No</web:lftgtReqDel>"
    SoapStr = SoapStr & "<web:lftgtRqrdPckup>No</web:lftgtRqrdPckup>"
    SoapStr = SoapStr & "<web:lmtAccessDel>No</web:lmtAccessDel>"
    SoapStr = SoapStr & "<web:lmtdAccessPckup>No</web:lmtdAccessPckup>"
    SoapStr = SoapStr & "<web:origCity>Burnsville</web:origCity>"
    SoapStr = SoapStr & "<web:origState>MN</web:origState>"
    SoapStr = SoapStr & "<web:origZip>55337</web:origZip>"
    SoapStr = SoapStr & "<web:palletCount>1</web:palletCount>"
    SoapStr = SoapStr & "<web:palletType>PALLETS</web:palletType>"
    SoapStr = SoapStr & "<web:password></web:password>"
    SoapStr = SoapStr & "<web:paymentType>P</web:paymentType>"
    SoapStr = SoapStr & "<web:prvtRsdncDel>No</web:prvtRsdncDel>"
    SoapStr = SoapStr & "<web:prvtRsdncPckup>No</web:prvtRsdncPckup>"
    SoapStr = SoapStr & "<web:shipDate>10/02/2017</web:shipDate>"
    SoapStr = SoapStr & "<web:usePalletPricing>No</web:usePalletPricing>"
    SoapStr = SoapStr & "<web:username></web:username>"
    SoapStr = SoapStr & "</web:criIn>"
    SoapStr = SoapStr & "</web:getCustomerRate>"
    SoapStr = SoapStr & "</soapenv:Body>"
    SoapStr = SoapStr & "</soapenv:Envelope>"
    goUrl.Text = "Http://www.lme4me.com:80/webapp/CustomPricing/services/CRIMethods"

    Try

        SoapByte = Encoding.UTF8.GetBytes(SoapStr)

        'Create initial request
        Dim request As HttpWebRequest = HttpWebRequest.Create(goUrl.Text)
        request.Proxy = Nothing 'Speeds up the request by setting the proxies to nothing
        request.UserAgent = "Test" 'We should not be worried about this.
        request.PreAuthenticate = False
        request.Method = "POST"
        request.ContentType = "Text/ Xml;charset=UTF-8"
        'request.Headers.Add("SOAPAction", "http://www.lme4me.com:80/webapp/CustomPricing/services/CRIMethods/getCustomerRate")
        request.Headers.Add("SOAPAction", "getCustomerRate")

        'request.ContentLength = 2215
        request.Host = "www.lme4me.com:80"
        'request.Connection = "Keep-Alive"
        request.UserAgent = "Apache-HttpClient / 4.1.1 (java 1.5)"

        'Create the Response and reader
        Dim response As HttpWebResponse = request.GetResponse()
        Dim responseHdr As String = request.GetResponse.ResponseUri.ToString()
        Dim responseStream As IO.Stream = response.GetResponseStream()
        'Create a new Stream reader
        Dim streamReader As New System.IO.StreamReader(responseStream)
        Dim Data As String = streamReader.ReadToEnd

        streamReader.Close()

        ' Display the Data on the screen
        UrlResponseText.Text = Data

    Catch ex As WebException

        MsgBox("Inproper input: " + Err.Description)
        goUrl.Text = ""
        If (ex.Status = WebExceptionStatus.ProtocolError) Then
            Dim error1 As String = New IO.StreamReader(ex.Response.GetResponseStream()).ReadToEnd()
            MsgBox("Rest of Error: " + error1.ToString())
        End If
    End Try

End Sub

Private Sub goUrl_TextChanged(sender As Object, e As EventArgs) Handles goUrl.TextChanged

End Sub

End Class

I can not seem to find much help for doing this in Visual Basic / VB.

A couple thoughts: 1) Reconsider loading your XML into an XmlDocument, to be certain, you don't have and XML error. Building XML in a string is frequently a problem 2) Most SOAP servers require the content length to be supplied (yours is commented out). 3) If the service provider makes a WSDL available, use it to build your request. — William Walseth
– William Walseth, Commented Nov 8, 2017 at 21:14
VB gave me an error on the length as I thought I needed it also. I don't understand what you mean by use the WSDL to build my request? I copied and Pasted the request from SoapUI and created the string code. — StephanM
– StephanM, Commented Nov 8, 2017 at 21:21
@StephanM - Here is a link about WSDLs: w3.org/TR/2007/REC-wsdl20-20070626 You can add a Web Reference with it and Visual Studio will wire up proxy classes to make it easy to call. — NoAlias
– NoAlias, Commented Nov 8, 2017 at 22:27
I have the web reference What I don't have are any VB examples that use it. I tried creating the VB with SoapUI and that has me confused at where you even start. In the code I posted that I pulled from the video I think I am missing where I pass my xml SoapStr into request. — StephanM
– StephanM, Commented Nov 9, 2017 at 0:01
I tested you code and get same error. I captured http messages with wireshark (a sniffer) and didn't get any additional info. It looks like you are missing headers (or bad headers) in the http request. The documentation on the webpage requires a login so I couldn't not verify you initial request contains the correct headers. Need a sample of the headers from server documentation. Best method of debugging code is to download for free a sniffer like wireshark or fiddler. I would modify your code to only include http headers that are shown in vendors documentation and not sample from U-TUBE — jdweng
– jdweng, Commented Nov 9, 2017 at 3:52

P.Manthe · Accepted Answer · 2017-11-09 02:35:23Z

1

I cannot see in your code where you are actually using your soapStr/soapByte.

Here is some generic code we are using:

Friend Function PostWebservice(soapAction As String, xmlBody As String) As XmlDocument

    Dim uTF8Encoding As New UTF8Encoding()
    Dim bytes As Byte() = uTF8Encoding.GetBytes(xmlBody)

    Dim requestUriString As String = "Whatever.com"

    Dim httpWebRequest As HttpWebRequest = CType(WebRequest.Create(requestUriString), HttpWebRequest)
    httpWebRequest.Headers.Add(HttpRequestHeader.AcceptEncoding, "gzip, deflate")
    httpWebRequest.Headers.Add("SOAPAction", soapAction)
    httpWebRequest.Method = "POST"
    httpWebRequest.ContentType = "text/xml; charset=utf-8"
    httpWebRequest.ContentLength = CLng(bytes.Length)

    Dim requestStream As Stream = httpWebRequest.GetRequestStream()
    requestStream.Write(bytes, 0, bytes.Length)
    requestStream.Close()

    Dim httpWebResponse As HttpWebResponse = CType(httpWebRequest.GetResponse(), HttpWebResponse)
    Dim streamReader As StreamReader = New StreamReader(httpWebResponse.GetResponseStream(), uTF8Encoding)

    Dim xmlDocument As New XmlDocument()
    xmlDocument.LoadXml(streamReader.ReadToEnd())
    httpWebResponse.Close()
    Return xmlDocument

End Function

answered Nov 9, 2017 at 2:35

P.Manthe

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1 Comment

StephanM Over a year ago

I discovered that yesterday, but still looking for how to pass them in VB.

StephanM · Accepted Answer · 2017-11-09 15:30:01Z

I had found that I was not passing the SoapStr and needed to add some additional code to write it.

DataStream = Request.GetRequestStream() DataStream.Write(SoapByte, 0, SoapByte.Length) DataStream.Close()

So now the code looks like this:

 SoapByte = System.Text.Encoding.UTF8.GetBytes(SoapStr)

        'Create initial request
        Request = WebRequest.Create(goUrl.Text)
        Request.Headers.Add("SOAPAction", "http://www.lme4me.com:80/webapp/CustomPricing/services/CRIMethods/getCustomerRate")

        Request.ContentType = "Text/ Xml; charset=UTF-8"
        Request.ContentLength = SoapByte.Length
        Request.Method = "POST"

        DataStream = Request.GetRequestStream()
        DataStream.Write(SoapByte, 0, SoapByte.Length)
        DataStream.Close()

        Response = Request.GetResponse()
        DataStream = Response.GetResponseStream()
        Reader = New StreamReader(DataStream)
        Dim Data As String = Reader.ReadToEnd()

        DataStream.Close()
        Reader.Close()
        Response.Close()

        ' Display the Data on the screen
        UrlResponseText.Text = Data

This seems to work correctly for me.

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