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

The PHP function preg_grep handles this beautifully. It accepts the Regex pattern and the array to search for as its parameters. It then returns the array consisting of the elements of the input array that match the given pattern. The returned array is indexed using the keys from the input array.

Here is my array:
Array
(
[0] => Armenia
[1] => America
[2] => Algeria
[3] => India
[4] => Brazil
[5] => Croatia
[6] => Denmark
)
I want to find all the countries in the array which start with the letter ‘A’. We need to form a regular expression which will match all the strings starting with letter A.

I have got this simple regular expression: ‘/^A.*/’

Now here is the PHP code to find the values from the Array.

<?php
$array = array('Armenia', 'America', 'Algeria', 'India', 'Brazil', 'Croatia', 'Denmark');
$fl_array = preg_grep('/^A.*/', $array);
echo '<pre>';
print_r($fl_array);
echo '</pre>';
?>

Which then gives you this output:
Array
(
[0] => Armenia
[1] => America
[2] => Algeria
)

Here are some Regular Expression Patterns you could use.

Find whole numbers: ‘/^\d+$/’
Floating numbers: ‘/^\d+\.{1}\d+$/’
Lowercase Words: ‘/^[a-z]+$/’

Play with Regular Expressions and let me know if you have any questions or if you need more patterns. I am planning to publish an article on Regular Expressions soon.

I wanted one of my web applications to have a different appearance on mobile phones and devices. I didn’t really want to set up an entirely different domain or use a sub domain particularly for mobile devices (like http://mobile.facebook.com). Instead I want to tackle the device inside my application logic so that all users access the same URL.

PHP’s $_SERVER['HTTP_USER_AGENT'] is cool. You can play around this variable and achieve what you want. But you don’t get all you want. Let’s look at the string output of the above variable on my browser:

Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2.6) Gecko/20100625 Firefox/3.6.6 (.NET CLR 3.5.30729)

This gives you some information. I wanted an easy way to see whether the request was from a mobile device.

PHP has this function, get_browser which attempts to determine the capabilities of the user’s browser, by looking up the browser’s information in the browscap.ini file.

In order for this to work, your browscap configuration setting in php.ini must point to the correct location of the browscap.ini file on your system. browscap.ini is not bundled with PHP, but you may find an up-to-date » php_browscap.ini file here. While browscap.ini contains information on many browsers, it relies on user updates to keep the database current.

First, Download the browscap.ini file for PHP from the above website. There are many files and this is the one you need: Gary Keith’s browscap.ini for PHP

Now, open your PHP.ini file and find for “browscap”. You will see something like this:

[browscap]
;browscap = extras\browscap.ini

Remove the semicolon and change the path to point to the php_browscap.ini you just downloaded. Your PHP.ini directive now looks like this:

[browscap]
browscap = C:\Inetpub\PHP5\extras\php_browscap.ini

Save the PHP.ini file and restart your Web server.

Now use the get_browser function in your PHP code to get user’s browser properties and capabilities.

<?php
$browser = get_browser(null, true);
echo "<pre>";
print_r($browser);
echo "</pre>";
?>

This is the output I got when I accessed the script using a Computer Browser.

Array
(
    [browser_name_regex] => ^mozilla/5\.0 (windows; .*; windows nt 5\.1; .*; rv:1\.9\.2.*) gecko/.* firefox/3\.6.*$
    [browser_name_pattern] => Mozilla/5.0 (Windows; *; Windows NT 5.1; *; rv:1.9.2*) Gecko/* Firefox/3.6*
    [parent] => Firefox 3.6
    [platform] => WinXP
    [win32] => 1
    [browser] => Firefox
    [version] => 3.6
    [majorver] => 3
    [minorver] => 6
    [frames] => 1
    [iframes] => 1
    [tables] => 1
    [cookies] => 1
    [javaapplets] => 1
    [javascript] => 1
    [cssversion] => 3
    [supportscss] => 1
    [alpha] =>
    [beta] =>
    [win16] =>
    [win64] =>
    [backgroundsounds] =>
    [cdf] =>
    [vbscript] =>
    [activexcontrols] =>
    [isbanned] =>
    [ismobiledevice] =>
    [issyndicationreader] =>
    [crawler] =>
    [aol] =>
    [aolversion] => 0
)

When I accessed the same script using a mobile phone, here’s what I got:

Array
(
    [browser_name_regex] => ^.*nokia.*/.*$
    [browser_name_pattern] => *Nokia*/*
    [parent] => Nokia
    [browser] => Nokia
    [tables] => 1
    [cookies] => 1
    [ismobiledevice] => 1
    [version] => 0
    [majorver] => 0
    [minorver] => 0
    [platform] => unknown
    [frames] =>
    [iframes] =>
    [javaapplets] =>
    [javascript] =>
    [cssversion] => 0
    [supportscss] =>
    [alpha] =>
    [beta] =>
    [win16] =>
    [win64] =>
    [backgroundsounds] =>
    [cdf] =>
    [vbscript] =>
    [activexcontrols] =>
    [isbanned] =>
    [ismobiledevice] =>
    [issyndicationreader] =>
    [crawler] =>
    [aol] =>
    [aolversion] => 0
)

I was just looking at this,

[ismobiledevice] => 1

Interesting uh!

If your shared hosting service doesn’t allow you to modify the PHP.INI file, you would want to use a stand alone implementation of the same concept by Jonathan. http://code.google.com/p/phpbrowscap/

It would look something like this:
Select * from tables where CREATE_TIME >= "2007-03-14 00:00:00" and CREATE_TIME <= "2007-03-16 23:59:59"

CakePHP has built-in functions to format a query like this if you have two dates, the FROM DATE and the TO DATE.

See the Example below:

$from = '14-Mar-2007';
$to = '16-03-2007';
App::import('Helper', 'Time');
$time = new TimeHelper();
echo '('.$time->daysAsSql(($from)?$from:$to, ($to)?$to:$from, "created").')';

In this example, we have two variables to store FROM and TO date limits. The function we used here is “daysAsSql’ and its a method available with the Time Helper Class. Basically these helper functions are designed to use in Views. When we need to use Helper functions in  a Controller, we import the Helper using the App:import function.

After importing the Time Helper into your controller, create an instance of the Time Helper, $time = new TimeHelper();

Now call this function by passing the date ranges and the field name as parameters. $time->daysAsSql(($from)?$from:$to,  ($to)?$to:$from, “date_field”)
I have additional calculations here: ($from)?$from:$to & ($to)?$to:$from. This makes sure that, if one of the date input values are null or not defined, it searches all the records with the date_field value on a particular day. Explained below.

The above example outputs this:

((created >= ‘2007-03-14 00:00:00′) AND (created <= ‘2007-03-16 23:59:59′))

Now you can use this as a Condition in your Find functions or as a Filter in your Pagination queries.

Examples:

$filters = array();
$filters = '('.$time->daysAsSql(($from)?$from:$to, ($to)?$to:$from, "created").')';
$records = $this->paginate('ModelName', $filters);

or

$conditions = array();
$conditions = '('.$time->daysAsSql(($from)?$from:$to, ($to)?$to:$from,  "created").')';
$this->data = $this->ModelName->find('all', array('conditions' => $conditions));

If $from was null the query generated would look like this:
((created >= ‘2007-03-16 00:00:00′) AND (created <= ‘2007-03-16 23:59:59′))

Please let me know if you have any questions.

I am using a Dell Vostro 1520 laptop and recently I came across this problem. My laptop hangs randomly and every time it does (it freezes stops responding completely), I have to restart my laptop by pressing the Power button for a few seconds. If some music was being played when it hangs, you now hear a buzzing noise. My OS is Windows XP Service Pack 3. I had absolutely no idea about the reason why my system hangs. When I looked at the event logs, I could see Netlogon errors being thrown when the system hangs. I did everything I could do to prevent a Netlogon error but with no luck. The Netlogon errors made me think that the problem could be with the Domain Controller since I’m on a Network. I also tried updating my BIOS and re-installing the Network Driver.

Finally I realized that the problem NEVER happens when I use my laptop on Battery Mode without an External AC Power supply. But as soon as I re-connect my AC Power supply, the system hangs. I found out that system hangs when on Low Battery with an AC Power outlet connected. It never hangs if you run only on your battery or if you run on your AC power with a fully charged battery.

The real problem was with the Intel SpeedStep technology which changes some settings to optimize the laptop performance when you switch from one mode of power supply to other (from Battery to AC after using on battery for a while).

To immediate solution to this problem is to change the Power Option Properties (Power Schemes) in your OS.

In Windows XP:

• Right click on the Desktop and choose Properties.
• Click on ScreenSaver Tab and Click on “Power” button at the bottom.
• From the Power Schemes drop down, Choose “Always On”.
• Apply the settings and the problem is solved!

In Windows Vista or Windows 7, you can find Power Schemes (Power Plans) option in Control Panel to choose a Power Plan. Choose “High Performance” which will disable the Intel SpeedStep.

This problem is often seen in Dell Laptops and you can contact Dell for a replacement if you are covered under a warranty.

<?php
$tmp = $a;
$a = $b;
$b = $tmp;
?>

Here is another way without using a temp or a third variable.

<?php
list($b, $a) = array($a, $b);
?>

And if you want to make it a function:

<?php
function swapValues(&$a, &$b) {
     list($b, $a) = array($a, $b);
 }
$a = 10;
$b = 20;
swapValues($a, $b);
?>

But if you have used plug-ins in your application, and if a user tries to access a controller action of a plug-in the user is redirected to an invalid page like this.

http://domain.com/plugin_name/users/login

This is because, CakePHP assumes the user controller to be a a part of the Plug-in.

Normally, your beforeFilter function could look like this.

function beforeFilter() {
	Security::setHash('md5');
	$this->Auth->loginAction = array('controller' => 'users', 'action' => 'login');
	$this->Auth->loginRedirect = array('controller' => 'home', 'action' => 'index');
	$this->Auth->loginError = 'Invalid Username or Password.';
	$this->Auth->authError = "You are not authorized to access.";
	$this->Auth->logoutRedirect = array('controller' => 'users', 'action' => 'login');
}

The redirection problem can be avoided by defining the loginAction in the above function like this:

$this->Auth->loginAction = array(’controller’ => ‘users’, ‘action’ => ‘login’, ‘plugin’ => null);

This tells CakePHP that the user controller is a global controller.

The same problem occurs when you use $html->link or $html->url to generate links to global contoller actions from a plugin view. If you didn’t define the parameter ‘plugin’=>true in $html->link or $html->url, CakePHP will assume the controller to be a part of the current plugin and will try to access a controller within the plugin instead of redirecting the user to the global controller.

The below code passes a string array in PHP to Javascript.

<?php
$arr = array("a","b","c");
?>
<script>
var jsArray = ["<?php echo join("\", \"", $arr); ?>"];
alert(jsArray);
</script>

I faced this when I had to load some User Session values (which is stored in a database table) in my AppController (app_controller.php) to use with a custom Login process. I was actually integrating a single sign-on process in CakePHP with an external application.

The loadModel function came handy here. See the code below.

$this->loadModel(’UserSession’);
debug($this->UserSession->find(’all’));

By just calling the loadModel function and passing the Model name, the model now becomes available to the controller and we could perform any operations on that model.

By using loadModel, we can reduce the overhead of declaring model names in $uses variable.

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.