Creating a file on server, using Flash AS3 + PHP

Question

I have a very simple PHP script that creates a new file on my server using a random number for the file name (e.g., 412561.txt).  When I load the script directly from a browser, it works.  But when I load the script from a very simple Flash (AS3) script, it does not work (i.e., doesn't create a file).  The Flash script and PHP script are both in the same directory.  Permissions on the directory and its content are 755.  Temporarily setting those permissions to 777 does not solve the problem (i.e., PHP still doesn't create file when called via Flash).
Here is my phpinfo.
Here is the PHP file.
The contents of the PHP file are:
<?php
error_reporting(E_ALL);
ini_set("display_errors", 1);
$RandomNumber = rand(1,1000000);
$filename = "$RandomNumber" . ".txt";
$filecontent = "This is the content of the file.";
if(file_exists($filename))
          {$myTextFileHandler = fopen($filename,"r+"); }
else
          {$myTextFileHandler = fopen($filename,"w"); }
if($myTextFileHandler)
          {$writeInTxtFile = @fwrite($myTextFileHandler,"$filecontent");}     
fclose($myTextFileHandler);   
?>
Here is the html container for the Flash script.  The Flash script features a single button which calls the PHP script when pressed.  In case it helps, here is the raw Flash file itself.  The code of the Flash script is as follows:
stop();
var varLoader:URLLoader = new URLLoader;
var varURL:URLRequest = new URLRequest("http://www.jasonfinley.com/research/testing/TestingSaveData.php");
btnSave.addEventListener(MouseEvent.CLICK,fxnSave);
function fxnSave(event:MouseEvent):void{
          btnSave.enabled=false;
          varLoader.load(varURL);
Directory listing is enabled at the parent directory here, so you can see there when a new text file is created or not.  (Um, if this is a security disaster, please let me know!)
Can anyone please help me understand why this isn't working and how I can fix it?  Thank you
~jason

Answer 1

#1, Yes that is a security risk, please disable directory index viewing.
#2, Always validate. I see no issue with the code you're using but clearly it's not working. The way you find out is your trusty errors.
Make a new document (or paste this into your existing) where a button with the instance name btnSave is on screen:
// import required libs
import flash.net.URLLoader;
import flash.net.URLRequest;
import flash.events.Event;
import flash.events.IOErrorEvent;
import flash.events.MouseEvent;
import flash.events.SecurityErrorEvent;
import flash.text.TextField;
// assign handler
btnSave.addEventListener(MouseEvent.CLICK, fxnSave);
// make a textfield to display status
var tf:TextField = new TextField();
addChild(tf);
tf.width = stage.stageWidth;
tf.height = 300;
tf.multiline = true;
tf.wordWrap = true;
tf.selectable = false;
tf.text = "Loading...\n";
// just making sure the textfield is below the button
this.swapChildren(tf,btnSave);
function fxnSave(event:MouseEvent):void
    // disable button
    event.currentTarget.enabled = false;
    // new loader
    var varLoader:URLLoader = new URLLoader();
    // listen for load success
    varLoader.addEventListener(Event.COMPLETE, _onCompleteHandler);
    // listen for general errors
    varLoader.addEventListener(IOErrorEvent.IO_ERROR, _onErrorHandler);
    // listen for security / cross-domain errors
    varLoader.addEventListener(SecurityErrorEvent.SECURITY_ERROR, _onErrorHandler);
    // perform load
    varLoader.load(new URLRequest("http://www.jasonfinley.com/research/testing/TestingSaveData.php"));
// complete handler
function _onCompleteHandler(e:Event):void
    tf.appendText("Load complete: " + e);
// error handler
function _onErrorHandler(e:Event)
    if (e.type == SecurityErrorEvent.SECURITY_ERROR)
        tf.appendText("Load failed, Security error: " + e + " type[" + e.type + "]");
    else if (e.type == IOErrorEvent.IO_ERROR)
        tf.appendText("Load failed, IO error: " + e + " type[" + e.type + "]");
I get a Event.COMPLETE for mine, so the PHP script is definitely firing. Change the URL to something invalid and you'll see the IOErrorEvent fire off right away.
That leaves you to diagnose the PHP script. Check your error_log and see what is going wrong. You're suppressing errors on your file write which doesn't help you locate the issue saving the file. If you want to handle errors yourself you should do the usual try/catch and handle the error yourself (write a debug log file, anything).