I normally share codes I write with the developer community. But there are occasions when I don’t want others to see the source code of my application. This could be when I have concerns over the security of my application or when it is a proprietary application built for a customer.  But unfortunately stealing the source code of a Flash SWF application is very easy. With reverse engineering technologies gaining popularity day by day among the Flash development communities, protecting the Actionscript code is a big problem. There are plenty of SWF decompilers like Sothink available in the market making it easy for anyone to decompile an SWF file fetched from a browser and see the whole source code written for the application.

This is when we need to really think about code security and protecting our source codes from being stolen. There are some flash protector applications available and I tried SWF Protector from DComSoft. It works out really well. The application is available for Windows, Mac and Linux. Protecting an SWF application using the SWF Protector is really easy. Add your SWF files to the SWF Protector and click on the Protect All button. The SWF Protector uses different algorithms for AS2 and AS3 versions. For AS2, it uses “Mix Script” and “Mask Script” methods which basically mix up functions, arguments and variables names, so it becomes difficult for understanding after de-compilation. For AS3, the code can be “Protected” which modifies the scripts in such way that SWF files can play in Flash player, but cannot be decompiled, or “Obfuscated” which renames variable and other objects in the code making it impossible to compile the code further.

There is another method to protect your SWF code without using any application. That is by creating a loader SWF which will embed the actual SWF as a byteArray and it can be loaded using Loader.loadBytes().

When someone tries to decomplile an SWF file which is protected using SWF Protector the code would look something like this.

do {
// unexpected jump
} while (true);
// swfAction0xAD hexdata 0x52,0x17,0x99,0x02,0x00,0x39,0x00,0x9A,0x01,0x00,0x00,0x99... // Unknown action
}
"holder1".holder1.loadMovie();
// unexpected jump
/* Error1016 */
// unexpected jump
do {
(this);// not popped
if (true) {
// unexpected jump
} while (this);
(this);// not popped
// unexpected jump
}
}
}
Set("\x0B\x1A\x13\x16", true);
} while (true);

Now you say, would this be useful for someone? No, of course!

The SWF Protector is not free but comes with a small price tag. But it’s more than worth the money you pay and better than concerning over the security of your code. You can get more information or buy this tool from http://www.dcomsoft.com

This task has now become very simple with ActionScript3, Flash Player 10 and as3CoreLibrary. We don’t need to send the BitmapData back to the server to process and create the image. A file can be saved direct from the flash to the user computer. This is possible of a cool new FileReference.save() feature added to Flash Player 10. hich allows the Flash Player to write to the local file system as long as the save request is requested by the user. Upon calling FileReference.save() the default file system dialog will open and user can save the data from the flash movie to their local machine. No server processing needed!

Please note that FileReference.save() can be only invoked if the invoke call is associated with an OnClick event.

Additionally we are using JPEGEncoder which comes with the as3corelib. You can download this library here: http://code.google.com/p/as3corelib/
After downloading copy the source files (the com folder) on to your Class path or your application root directory. Apart from the JPEGEncoder, this library is packaged with a lot of other classes related to Hasing, Text, Date etc.

This is how we save an image from a flash movie to a local machine.

1) Create a BitmapData object out of the MovieClip or the Loader.
2) Encode the BitmapData using the JPEGEncoder and form a ByteArray.
3) Use FileReference.save() to download the image on to the User machine.

See an example:
Create a blank Flash movie and name it as “ImageSave.fla”. In the same folder create “ImageSave.as” file and copy the below code in to it. You need the “com” folder copied from the as3corelib to this folder. I have a button on the stage named “save_mc” which triggers the saveImage function.

package {
	import flash.display.MovieClip;
	import flash.display.BitmapData;
	import flash.display.Loader;
	import flash.utils.ByteArray;
	import flash.net.FileReference;
	import flash.net.FileFilter;
	import flash.events.*;
	import flash.net.URLLoader;
	import flash.net.URLRequest;
	import com.adobe.images.JPGEncoder;
	public class ImageSave extends MovieClip {
		private var imgFile:URLRequest;
		private var img:MovieClip;
		private var imgLoader:Loader;
		private var file:FileReference;
		public function ImageSave() {
			imgFile = new URLRequest("coffee.jpg"); //change it to your image path
			imgLoader = new Loader();
			imgLoader.load(imgFile);
			imgLoader.contentLoaderInfo.addEventListener(Event.COMPLETE, onLoaded);
			save_mc.addEventListener(MouseEvent.CLICK, saveImage);
		}
		private function onLoaded(evt:Event):void {
			imgLoader.contentLoaderInfo.removeEventListener(Event.COMPLETE, onLoaded);
			imgLoader.cacheAsBitmap = true;
			addChild(imgLoader);
		}
		function saveImage(e:MouseEvent):void {
			var myBitmapData:BitmapData = new BitmapData(imgLoader.width, imgLoader.height);
			myBitmapData.draw(imgLoader);
			var jpgEncoder:JPGEncoder = new JPGEncoder(80);
			var imgByteData:ByteArray = jpgEncoder.encode(myBitmapData);
			file = new FileReference();
			file.browse(new Array(new FileFilter("Images (*.jpg, *.jpeg)", "*.jpg;*.jpeg")));
			file.save(imgByteData, "test.jpg");
		}
	}
}

For your convenience you can download a working copy of this sample here:
Download ‘SaveImagefromFlash’ SourceCode – CS4 [ZIP]

This sample contains the as3CoreLib, so you don’t need to download it separate. The FLA source can be opened only in CS4. However you can still open the AS file and explore the code.

Please let me know if you have any questions.

Many of the Batch process tools available cause errors while processing for a long time and the browsers try to abort the script by showing a warning alert to the user. I was successful in fixing this issue.

The photos were organized in Albums. The users could create albums in their Photo manage page. To give the users the ability to upload a bunch of photos together as a batch process, the tool was introduced. User can launch this Batch uploader tool from their account homepage and browse for Photos from their folders. The features of this uploader include the ability to add files from different folders to the list. The file list can be managed by removing selected files or adding more files in to the list. When the user is ready with the list of files, he/she can then choose an Album fro m the dropdown where these photos will be stored.

The Batch Uploader is developed using Action Script 2 and uses PHP as the backend to process the file upload. The current user ID can be passed to the flash module by defining a FlashVars variable as “userid” which will be passed to the PHP function when albums are requested or when the upload is processed.

Here is an example of passing a variable to flash from HTML using FlashVars.

//Object Tag Example:
<PARAM NAME=FlashVars VALUE="userid=10">
//Embed Tag Example:
<EMBED href="display.swf" FlashVars="userid=10"></EMBED>

The application initially request for the albums created by the user, by calling a PHP script which returns a list of albums and their ids in XML format.

See the code at line 86.

var albumListURL = (_root.albumUrl)?_root.albumUrl:"http://yourwebsite.com/albumList.php";

The albumList.php should return the list of Albums in XML format as shown below.

<?xml version="1.0" encoding="utf-8"?>
<albums>
	<album><id>1</id><name>My Little Baby</name></album>
	<album><id>2</id><name>Wedding Photos</name></album>
</albums>

The tool also allows the user to create a new album right from the uploader interface. Open the “albumpop_mc” movieclip on the stage to see the album creation functionalities.

The batch upload tool sends selected files one by one to the server. “uploadItem” (Line number 172) is the function which sends the file to the server PHP script.  

if (!itemRef.upload("http://yourwebsite.com/batchUploadProcess.php&album="+albumHash+"&user="+_root.userId)) {
	errorList.push("Failed to upload : "+item.name);
}

This code sends one file at a time to a php script named “batchUploadProcess.php” which receives the file at the server and add a record in the database. The ID of the album the user has chosen from the list and the user Id the application is given as a FlashVars variable are sent to the PHP script.

Below is the script I used to process the file sent from Flash.

switch($_FILES['Filedata']['error']) {
    case 1:
    case 2:
    case 3:
    case 6: die; break;
    case 4:
    case 0: break;
    default: die; break;
}
if ($_FILES['Filedata']['error'] == 0) {
    $fileInfo['photo'] = getimagesize($_FILES['Filedata']['tmp_name']);
    if ($fileInfo['photo'][2] != 2) die;
}
move_uploaded_file($_FILES['Filedata']['tmp_name'], "./photos/originals/YourFileName.jpg");
//Add your other codes here
echo "success";

Click the below link to download the source file in CS3 format.Free Batch Upload tool – Flash Action Script

If you are an intermediate flash programmer, you can easily understand the code flow. Modify and use the code wherever you want. I don’t really want to explain the complete code here. But you can contact me if you have any questions.