Consuming JSON and XML Webservices from an HTML Page using jQuery

http://aspalliance.com/2052_Consuming_JSON_and_XML_Webservices_from_an_HTML_Page_using_jQuery

Create ASP.NET 3.5 Sitemap XML for Navigational Web Controls

http://www.aspfree.com/c/a/ASP.NET/Create-ASPNET-35-Sitemap-XML-for-Navigational-Web-Controls/

The Power of Flex's resultFormat E4X

While researching how to bind XML data to a Flex AdvancedDataGrid, I saw various examples that had the data converted to array objects. That might have been the only way to work with XML prior to ActionScript 3.0. Now however, a new set of classes and functionality, known as E4X (ECMAScript-for-XML), make life easier for developers.

Playing around, I discovered that, on the HTTPService object, a simple property allows the data to be accessible via simple XML calls,

service.resultFormat = "e4x";

This enables your datagrid's columns' dataField to simply have your XML element or attribute name as its value. For example, to read an id attribute off of the root element of your XML, you'd use dataField="@id".

Flex and XML - Don't Forget the ContentType

Hi, all. Hope everyone had a great weekend. I came across an interesting problem last week with Flex 3: A Java servlet produced perfectly fine XML via the SAX (Simple API for XML) package, but the SWF file kept having a hiccup when it tried to read the data,

private function useHttpService():void {
service = new HTTPService();
service.url = "http://myserver/myServlet";
service.method = "POST";
service.addEventListener("result", httpResult);
service.addEventListener("fault", httpFault);
service.send();
}

private function httpResult(event:ResultEvent):void {
premiums = XML(event.result);

// Read the XML directly (E4X) in the datagrid.
this.dgPremiums.dataProvider = premiums.premium;
}

// Fetch the rootCause and display in Alert.
private function httpFault(event:FaultEvent):void {
var errorMessage:ErrorMessage = event.message as ErrorMessage;
Alert.show("rootCause: " + errorMessage.rootCause.toString());
}

In the above code, I changed the FaultEvent handler to display an object as an ErrorMessage, as per Sujit's great article. Finally, it showed the error,

IOErrorEvent type="ioError" bubbles=false cancelable=false eventPhase=2 text="Error #2032: Stream Error. URL: myServlet"

Hmm. Flex errors can sometimes be tricky. A quick check on a Flex error lookup tool, and this page provided some answers, though not what I thought. One person had posted about having to remove the contentType from the HTTPService object. Mine was missing it. So I added it and voila! Flex fetched the data with no errors.

A little more digging and I realized that my Java servlet was emitting XML data, with the contentType set to "text/xml". Flex needed that hint of what data to expect. So adding this line to the useHTTPService() method fixed the headache,

service.contentType = "application/xml"; // Must have this or will get IOError -- servlet generates XML document.