Source code – Page 4 – Alex Arriaga

alex-arriaga July 23, 2013

Reading an XML file by using Joomla 2.5 API – JFactory::getXML()

Joomla, PHP, Uncategorized, Web Development 2 Replies

Imagine the situation where you need to read a list of configuration permissions, these permissions are inside of an XML file called permisos.xml in a valid directory of your server. In this short article we will see how to read an XML file, parse it and create an array with all entries of this file. There are several ways to do this, but we will use the compatible option with Joomla 2.5 API, why? well, because Joomla 2.5 is the stable and recommended version -currently- of this CMS (Content Management System). So, please let me show you how to complete this task.

Next is a valid XML file:

<?xml version="1.0" encoding="utf-8"?>
<permisos>
   <grupo id="8" nombre="Administrators">
         <modulo nombre="COM_ADMIN_ORDER_MOD" visible="true">
            <menu nombre="COM_ORDER_S" visible="true"></menu>
            <menu nombre="COM_REPORT" visible="true"></menu>
            <menu nombre="COM_USER_S" visible="true"></menu>
            <menu nombre="COM_SHOPPERGROUP_S" visible="true"></menu>
            <menu nombre="COM_COUPON_S" visible="true"></menu>
         </modulo>
   </grupo>
 	<grupo id="11" nombre="Team Members">
   		<modulo nombre="COM_ADMIN_ORDER_MOD" visible="false">
   			<menu nombre="COM_ORDER_S" visible="false"></menu>
   			<menu nombre="COM_REPORT" visible="true"></menu>
   			<menu nombre="COM_USER_S" visible="false"></menu>
   			<menu nombre="COM_SHOPPERGROUP_S" visible="false"></menu>
   			<menu nombre="COM_COUPON_S" visible="false"></menu>
   		</modulo>
	</grupo>
</permisos>

<?xml version="1.0" encoding="utf-8"?>

</modulo>

</grupo>

</modulo>

</grupo>

</permisos>

Now, with this simple code we can read all this file using Joomla 2.5 classes and methods, in particular we will use the static method getXML() from JFactory.

$usuario =& JFactory::getUser();
$grupos_usuario = $usuario->groups;
$permisos = array();

	// Reading file
	$xmlfile = JURI::base().'/some_path/permisos.xml';
	$xml = JFactory::getXML($xmlfile,true);

	foreach($xml->children() as $grupo):
		$id_grupo_xml = $grupo->getAttribute("id");
		foreach($grupo->children() as $modulo):
			// Permissions by module
			foreach($grupos_usuario as $id_grupo):
				if(in_array($id_grupo_xml, $grupos_usuario))
					$permisos[$id_grupo][$modulo->getAttribute("nombre")] = $modulo->getAttribute("visible");
			endforeach;

			// Permissions for each menu entry in every one of the modules
			foreach($modulo->children() as $menu):
				foreach($grupos_usuario as $id_grupo):
					if(in_array($id_grupo_xml, $grupos_usuario))
						$permisos[$id_grupo][$menu->getAttribute("nombre")] = $menu->getAttribute("visible");
				endforeach;
			endforeach;
		endforeach;// all modules
	endforeach; // all groups

	echo "<pre>";
		print_r($permisos);
	echo "</pre>";

$usuario =& JFactory::getUser();

$grupos_usuario = $usuario->groups;

$permisos = array();

// Reading file

$xmlfile = JURI::base().'/some_path/permisos.xml';

$xml = JFactory::getXML($xmlfile,true);

foreach($xml->children() as $grupo):

$id_grupo_xml = $grupo->getAttribute("id");

foreach($grupo->children() as $modulo):

// Permissions by module

foreach($grupos_usuario as $id_grupo):

if(in_array($id_grupo_xml, $grupos_usuario))

$permisos[$id_grupo][$modulo->getAttribute("nombre")] = $modulo->getAttribute("visible");

endforeach;

// Permissions for each menu entry in every one of the modules

foreach($modulo->children() as $menu):

foreach($grupos_usuario as $id_grupo):

if(in_array($id_grupo_xml, $grupos_usuario))

$permisos[$id_grupo][$menu->getAttribute("nombre")] = $menu->getAttribute("visible");

endforeach;

endforeach;// all modules

endforeach; // all groups

echo "<pre>";

print_r($permisos);

echo "</pre>";

After reading content of the XML file we will get an output like this:

Array
(
    [8] => Array
        (
            [COM_ADMIN_ORDER_MOD] => true
            [COM_ORDER_S] => true
            [COM_REPORT] => true
            [COM_USER_S] => true
            [COM_SHOPPERGROUP_S] => true
            [COM_COUPON_S] => true
        )

)

Array

(

[8] => Array

(

[COM_ADMIN_ORDER_MOD] => true

[COM_ORDER_S] => true

[COM_REPORT] => true

[COM_USER_S] => true

[COM_SHOPPERGROUP_S] => true

[COM_COUPON_S] => true

)

As you can see, it is really easy to read XML files, if you have some comments about this, please let me know.

Be happy with your code!

—

Alex Arriaga

alex-arriaga July 22, 2013

Validating if a jQuery plugin exists before running code that use it

jQuery, Web Development No Reply

When we are creating plugins or simple code in jQuery and there is a single or many plugin dependences among them, a common task is to implement a mechanism to validate if a jQuery plugin exists before running “depending” code, for example if we have this code and we have not included jqprint (a nice plugin to print a fragment of an HTML document), then an error will appear indicating that jqprint function is undefined.

(function($) {
    $(document).ready(function() {
        $(".print-this-section").on('click', function(){
            $("#section-to-print").jqprint();
        });
    });
})(jQuery);

(function($) {

$(document).ready(function() {

$(".print-this-section").on('click', function(){

$("#section-to-print").jqprint();

});

})(jQuery);

So, in order to solve this “undefined” error we could add a little validation before running jqprint code.

(function($) {
    $(document).ready(function() {
 		if( jQuery().jqprint ){ // Verifying jqprint exists
	        $(".print-this-section").on('click', function(){
	            $("#section-to-print").jqprint();
	        });
		}
    });
})(jQuery);

(function($) {

$(document).ready(function() {

if( jQuery().jqprint ){ // Verifying jqprint exists

$(".print-this-section").on('click', function(){

$("#section-to-print").jqprint();

});

}

});

})(jQuery);

With this simple code, you would be able to avoid errors in your code when a plugin is not defined.

That’s it!

Be happy with your code!

—

Alex Arriaga

alex-arriaga July 17, 2013

How to set expiry date of a cookie (using jQuery Cookies plugin)

jQuery, Web Development 2 Replies

In a previous post I explained what is the process for Saving a complex JSON object in a cookie by using jQuery (demo included in PHP). Now, I would like to add some related information about how to set an expiry date of a cookie using the same plugin (jQuery Cookies).

First of all, it is important to know that an expire date is just a valid JavaScript Date Object, I mean, you will only need to create a date and then assign this to an array of options when you save your data in a cookie. Let me explain using a little example:

function setUserConfigInCookie(){
      var expireDate = new Date;
      expireDate.setDate(expireDate.getDate() + 7); // It expires in a week

      var options = {
        path: '/',
        expiresAt: expireDate
      }

      userConfig = {}; // This is a valid JSON object that you need to save in a cookie
      $.cookies.set( 'userConfig', userConfig, options);

      // console.log('Expires=' + expireDate.toGMTString());
    }

function setUserConfigInCookie(){

var expireDate = new Date;

expireDate.setDate(expireDate.getDate() + 7); // It expires in a week

var options = {

path: '/',

expiresAt: expireDate

}

userConfig = {}; // This is a valid JSON object that you need to save in a cookie

$.cookies.set( 'userConfig', userConfig, options);

// console.log('Expires=' + expireDate.toGMTString());

}

With this simple code we can save a cookie (complex JSON object) and set an expiry date (in this example the cookie is going to expire in a week). If you want to verify that all is working, you could search for your cookie in your favorite browser, for example next image uses Firefox to see this cookie:

That’s it at this moment.

Be happy with your code!

—

Alex Arriaga

alex-arriaga July 16, 2013

How to use and understand Binary Search on Java SE

Enterprise Development, Java EE 2 Replies

Java is a Platform to create robust, secure and scalable stand-alone and enterprise web applications. It has a lot of classes and resources that make easy to develop many functionalities in systems. One of the most interesting parts of the Java API (Application Programming interface) is work with collections and generics. Basically, Java has three kinds of “collections”: Set, List and Map (this one is not necessarily a collection but it is enough alike than one, so its use doesn’t cause any problem, if we understand how collections work).

Well, in Java there is a special static class called Arrays (java.util.Arrays),

This class contains various methods for manipulating arrays (such as sorting and searching). This class also contains a static factory that allows arrays to be viewed as lists.

Today, I would like to show you how to use a method that implements Binary Search, but before we could check the official information about this method:

Binary Search method. Searches the specified array of ints for the specified value using the binary search algorithm. The array must be sorted (as by the sort(int[]) method) prior to making this call. If it is not sorted, the results are undefined. If the array contains multiple elements with the specified value, there is no guarantee which one will be found.

This method has a lot of overrides, for more information about them, please visit: http://docs.oracle.com/javase/6/docs/api/java/util/Arrays.html#binarySearch(java.lang.Object[], java.lang.Object)

Now, imagine that we have the next code:

import java.util.*;

public class ArraysTest{
	public static void main(String [] args) {
		String [] colors = {"blue", "red", "green", "yellow", "orange"};

		// It is necessary to have an ordered array
		Arrays.sort(colors);
		for(String color : colors)
			System.out.print(color + " ");

		int index1 = Arrays.binarySearch(colors, "orange");
		int index2 = Arrays.binarySearch(colors, "violet");
		System.out.println("\norange => " + index1);
		System.out.println("violet => " + index2);
	}
}

import java.util.*;

public class ArraysTest{

public static void main(String [] args) {

String [] colors = {"blue", "red", "green", "yellow", "orange"};

// It is necessary to have an ordered array

Arrays.sort(colors);

for(String color : colors)

System.out.print(color + " ");

int index1 = Arrays.binarySearch(colors, "orange");

int index2 = Arrays.binarySearch(colors, "violet");

System.out.println("\norange => " + index1);

System.out.println("violet => " + index2);

}

The output is something like this:

blue green orange red yellow
orange => 2
violet => -5

blue green orange red yellow

orange => 2

violet => -5

According to the API:

Parameters:
- a – the array to be searched
- key – the value to be searched for
Returns:
- index of the search key, if it is contained in the array; otherwise, (-(insertion point) – 1). The insertion point is defined as the point at which the key would be inserted into the array: the index of the first element greater than the key, or a.length if all elements in the array are less than the specified key. Note that this guarantees that the return value will be >= 0 if and only if the key is found.
Throws:
- ClassCastException – if the search key is not comparable to the elements of the array.

Explanation

The first result after searching for “orange” is clear because “orange” was found in the index: 2.

Second result is a little more complex. Let me ask you, was “violet” found in the array? what should the index where “violet” be inserted? Well, see next image to understand better:

As you can see index:4 is where “violet” should be inserted. For this reason binarySearch return -5 (see next operation for more details):

-(insertion point) - 1 = -(4) -1 = -5

1	-(insertion point) - 1 = -(4) -1 = -5

That’s it, at this moment.

Be happy with your code!

—

Alex Arriaga

alex-arriaga July 10, 2013

Saving a complex JSON object in a cookie by using jQuery (demo included in PHP)

jQuery, Web Development 8 Replies

Today, I spent almost three hours to test and implement a mechanism to save a complex JSON object and get it to render in a HTML output,, for this reason I would like to explain what was the ~~best~~ easiest way that I found for saving my object.

First, I would recommend you to be sure that your object is well-created, I mean, it is important that your JSON object is according to JavaScript Object Notation (you can visit this link to read more about: http://www.json.org/).

Second, I have used some compatible plugins with jQuery (I have tested this plugins using jQuery 1.8.2, this because in my project jQuery had already existed, also I have tested in jQuery 1.10.2), In a nutshell, we need the next JavaScript files:

Creating our complex JSON object

I have decided to use PHP to create our testing object (because most of developers have knowledge in this programming language).

// An array to simulate a complex JSON object
		$userSettings =  array(
			"personal_information" => array(
				"name" => "Alex",
				"last_name" => "Arriaga"
				),
			"extra_information" => array(
				"twitter" => "alex_arriaga_m",
				"facebook" => "alex.arriaga.m",
				"website" => "http://www.alex-arriaga.com/",
				"programming_languages" => array("HTML5", "CSS3", "JavaScript", "PHP", "Java", "C# .NET", "AWK", "LESS", "XML")
			)
		);

		// Creating the JSON object
		$jsonObject = json_encode($userSettings);

// An array to simulate a complex JSON object

$userSettings = array(

"personal_information" => array(

"name" => "Alex",

"last_name" => "Arriaga"

"extra_information" => array(

"twitter" => "alex_arriaga_m",

"facebook" => "alex.arriaga.m",

"website" => "http://www.alex-arriaga.com/",

"programming_languages" => array("HTML5", "CSS3", "JavaScript", "PHP", "Java", "C# .NET", "AWK", "LESS", "XML")

)

);

// Creating the JSON object

$jsonObject = json_encode($userSettings);

Saving and getting our complex JSON object

Now, we can create a simple JavaScript code to save our JSON object and get it later.

	(function($){
		$(document).on('ready', function(){
			//A cookie by the name 'userSettings' now exists with a serialized copy of $userSettings
			$.cookies.set( 'userSettings', <?php echo $jsonObject; ?> );

			//A variable named 'userSettings' now holds the unserialized object, it should be identical to the PHP variable 'userSettings'
			var userSettings = $.cookies.get( 'userSettings' );

			// Do something with the values read from cookie
			console.log(userSettings);
		});
	})(jQuery);

(function($){

$(document).on('ready', function(){

//A cookie by the name 'userSettings' now exists with a serialized copy of $userSettings

$.cookies.set( 'userSettings', <?php echo $jsonObject; ?> );

//A variable named 'userSettings' now holds the unserialized object, it should be identical to the PHP variable 'userSettings'

var userSettings = $.cookies.get( 'userSettings' );

// Do something with the values read from cookie

console.log(userSettings);

});

})(jQuery);

Verifying result

To see the saved object please use Firebug (in cookie tab). See next images like a demo of this.

Figure 1. Saving JSON object

Figure 2. Getting JSON object and verifying in Firebug console

It is possible to configure several parameters, but I think is better for you read them in the official github page of this plugin: https://code.google.com/p/cookies/

You can download this example code for testing more parameters or personalize according to your project. Download here.

That’s it. Be happy with your code!

—

Alex Arriaga

alex-arriaga June 28, 2013

The easiest way to check if an element exists with jQuery

jQuery, Web Development 1 Reply

When you need to know if an element exists in the DOM (Document Object Model), only uses this small code:

<script type="text/javascript">
(function($){
	$(document).on('ready', function(){
		if( $("element").length ){
			// Do something :)
		}
	});
})(jQuery);	
</script>

(function($){

$(document).on('ready', function(){

if( $("element").length ){

// Do something :)

}

});

})(jQuery);

</script>

The length property returns the number of elements that match with our selector. For example, imagine that you have the next HTML estructure:

<div class="parent">
	<ul>
		<li><a href="#">Some link</a></li>
	</ul>
	<div class="child"></div>
</div>

<ul>

</ul>

</div>

If you want to know if the element with class=”child” exists, just it is necessary to do:

<script type="text/javascript">
(function($){
	$(document).on('ready', function(){
		if( $(".child").length ){
			alert("Child exists");
		}
	});
})(jQuery);	
</script>

(function($){

$(document).on('ready', function(){

if( $(".child").length ){

alert("Child exists");

}

});

})(jQuery);

</script>

That’s all at this moment, be happy with your code!

—

Alex Arriaga

alex-arriaga June 18, 2013

Source code for creating an awesome presentation in LaTeX (beamer package)

Computer Sciences, LaTeX No Reply

Hi, my friends!

Once more, I would like to share with you a source code that could help you create a fancy presentation when you are preparing a speech. This file contains all the resources that I used to do my final thesis presentation in LaTeX two years ago (Artifice: virtual cities builder by using cellular automata).

This source code allows to generate a PDF presentation with transition effects, images and a really good design that it is superior at the traditional way to do presentations.

I have used a package called LaTeX Beamer, the source code was compiled by using Texlive (http://www.tug.org/texlive/) and it was edited in Winefish (http://winefish.berlios.de/) on Linux Mint distribution (http://www.linuxmint.com/).

So, be happy and start to create an awesome presentation! Download source code HERE.

Compiled presentation with a blue template (PDF)

Compiled presentation with a red template (PDF)

What would you like to know about?

Alex Arriaga

Tag Archives:
Source code

Reading an XML file by using Joomla 2.5 API – JFactory::getXML()

Validating if a jQuery plugin exists before running code that use it

How to set expiry date of a cookie (using jQuery Cookies plugin)

How to use and understand Binary Search on Java SE

Saving a complex JSON object in a cookie by using jQuery (demo included in PHP)

The easiest way to check if an element exists with jQuery

Source code for creating an awesome presentation in LaTeX (beamer package)

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