Parsing XML response from web service in AL

jonathanchye

Hi all,

I'm a little new to this so please bear with me.
I have so far managed to make a call to the endpoint however struggling to parse the response.
Below is sample of code I've used to parse send the request:

            Client.DefaultRequestHeaders.Add('AuthToken', AuthToken);      
            if Carrier <> '' then      
                Client.DefaultRequestHeaders.Add('Carrier', Carrier);

            clear(tempBlob);
            clear(lInStream);
            clear(lOutStream);

            tempBlob.Blob.CreateOutStream(lOutStream);
            tempBlob.Blob.CreateInStream(lInStream);
            XMLParServ.Init(Postcode, CountryCode);
            XMLParServ.SetDestination(lOutStream);
            XMLParServ.Export;

            while not lInStream.EOS do begin
                lInStream.ReadText(TextXMLReq);
                TextXMLReqFull := TextXMLReqFull + TextXMLReq;
            end;
    
            Content.WriteFrom(TextXMLReqFull);  

            Client.Post(URLString, Content,Response);

            if not Response.IsSuccessStatusCode then  
                Error(WebServiceErr, Response.HttpStatusCode, Response.ReasonPhrase);

            clear(lInStream);
            Response.Content.ReadAs(TextXMLReqFull);   
            // Response.Content.ReadAs(lInStream);

For some odd reason I get an error response back from the endpoint if I use Response.Content.ReadAs(Instream).
Reading into text variable works and it's acceptable as the value I need in the response is less than 250 characters.

Below is example XML response.

<?xml version="1.0" encoding="UTF-8"?>
<ParcelServiceResponse>
   <Status>Success</Status>
   <Carriers>
      <Carrier Name="ABC" ServiceID="1" ServiceName="24hr" ParcelCost="1.23" Currency="GBP" />
      <Carrier Name="ABC" ServiceID="2" ServiceName="48hr" ParcelCost="2.34" Currency="GBP" />
   </Carriers>
</ParcelServiceResponse>

I've so far managed to parse the Status from response using this code:

            XmlDocument.ReadFrom(lInStream, lXmlDocument);

            if lXmlDocument.SelectSingleNode('//Status', lXmlNode) then
                respStatus := lXmlNode.AsXmlElement.InnerText;

However I can't parse the attribute value (ServiceID and ServiceName). I've tried the below but it won't find the value. I hope someone could kindly advise.

            if lXmlDocument.SelectNodes('//Carriers/Carrier', lXmlNodeList) then begin              

                foreach lCarriersNode in lxmlnodelist do
                begin    
                    if lCarriersNode.SelectSingleNode('ServiceID', lXmlNode) then
                        respServices := respServices +  lXmlNode.AsXmlElement.InnerText;
                end;
            end; 

I've had a look at this webpage (https://community.dynamics.com/nav/b/diveshboramsdnavblog/archive/2018/03/09/vs-code-xml-dom-management-part-2) and tried to use the GetAttribute function but can't seem to get it to work.

jonathanchye

Well what do you know, tried out something and it worked

for reference I've used this helper function:

    procedure GetAttributeValue(pXMLNode: XmlNode; pAttributeName: Text): Text
    var
        lXmlAttribute: XmlAttribute;
    begin
        if pXMLNode.AsXmlElement().Attributes().Get(pAttributeName, lXmlAttribute) then
            exit(lXmlAttribute.Value());
    end;

Below is how I used the function to get the attribute value:

            if lXmlDocument.SelectNodes('//Carriers/Carrier', lXmlNodeList) then begin            
                foreach lCarriersNode in lxmlnodelist do
                begin    
                    respServices := respServices + '\' + GetAttributeValue(lCarriersNode, 'ServiceID') + '-' + GetAttributeValue(lCarriersNode, 'ServiceName');

Now I need to figure out why I get a response from endpoint saying "please contact administrator" if I stream the request to the endpoint as below instead of passing the text variable.

            tempBlob.Blob.CreateOutStream(lOutStream);
            tempBlob.Blob.CreateInStream(lInStream);
            XMLParServ.Init(Postcode, CountryCode);
            XMLParServ.SetDestination(lOutStream);
            XMLParServ.Export;


            while not lInStream.EOS do begin
                lInStream.ReadText(TextXMLReq);
                TextXMLReqFull := TextXMLReqFull + TextXMLReq;
            end;
            
            Content.WriteFrom(lInStream);    
            //Content.WriteFrom(TextXMLReqFull); //this works

            Client.Post(URLString, Content,Response);

            if not Response.IsSuccessStatusCode then  
                Error(WebServiceErr, Response.HttpStatusCode, Response.ReasonPhrase);
 
             Response.Content.ReadAs(lInStream);

            XmlDocument.ReadFrom(lInStream, lXmlDocument);