How to implement a SOAP call using XDomainRequest in IE8

Question

I'm trying to call a WCF service using soap in IE8 and I can't seem to get my head around how xdr's work. Can they be used to pass xml to a soap endpoint?

Answer 1

Can they be used to pass xml to a soap endpoint?

We are basically talking about a POST request with a properly formatted XML SOAP payload and you can sure do that with the XDomainRequest object. Here is a basic example:

<script type="text/javascript">
    var xdr;

    function soapTest() {
        var data =  '<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:tem="http://tempuri.org/">' +
                    '   <soapenv:Body>' +
                    '      <tem:Add>' +
                    '         <tem:a>1</tem:a>' +
                    '         <tem:b>2</tem:b>' +
                    '      </tem:Add>' + 
                    '   </soapenv:Body>' +
                    '</soapenv:Envelope>';

        if (window.XDomainRequest) {
            xdr = new XDomainRequest();
            if (xdr) {
                xdr.onerror = function() { alert("an error occured"); };
                xdr.ontimeout = function() { alert("timeout"); };
                xdr.onload = function() { alert(xdr.responseText); }
                xdr.timeout = 10000;
                xdr.open("post", "http://SomeServer/SoapCalculator");
                xdr.send(data);
            } else {
                alert("Failed to create XDR");
            }
        } else {
            alert("XDR doesn't exist");
        }
    }
</script>

The payload in the example is for a web service exposing this contract. You could create a mock web service based on that WSDL on a server that responds with the Access-Control-Allow-Origin header. Then, if all goes well you should see a response like this:

You can then parse the response to extract the data you need instead of printing the raw string.

For troubleshooting also have a look at the following post: XDomainRequest - Restrictions, Limitations and Workarounds.