Joeflash’s Enigmacopaedia

The RPC Fault Security Error that wasn’t

Posted in Books, Flex, Community MX, Security by Joeflash on the February 1st, 2009

In the first chapter of our upcoming book Professional Flex 3, I built a simple RSS reader in just a few lines of code to demonstrate how easy it is to build a Flex application. I expanded on this application in a few recent articles at Community MX, creating a mini RSS feed reader for all the book authors. All was well, until one of our tech editors Matthew Fabb, told me that the reader I built was producing a dreaded security error. Good catch Matt!

Here’s the original RSS reader code used in the book:

  1. <?xml version="1.0" encoding="utf-8"?>
  2. <mx:Application xmlns:mx="feed://"
  3.     layout="absolute" creationComplete="RSSFeed.send();">
  4.     <mx:HTTPService id="RSSFeed" url="feed://http//"/>
  5.     <mx:List id="postTitles" labelField="title" left="20" right="20" top="20"
  6.         dataProvider="{}"/>
  7.     <mx:TextArea htmlText="{postTitles.selectedItem.description}"
  8.         left="20" right="20" top="190" height="200"/>
  9.     <mx:Button label="Go to page" left="20" top="400"
  10.         click="navigateToURL(new URLRequest(;" />
  11. </mx:Application>

I tried it locally, and no security error, of course. I loaded it onto my server, and I got the following error:

[RPC Fault faultString="Security error accessing url" faultCode="Channel.Security.Error" faultDetail="Destination: DefaultHTTP"] ...