Tag Archives: Computing

Quick Look at JavaScript Objects

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JavaScript Objects

As you may know there are different notations of objects in JavaScript, and there are slight differences. However here I’m gonna achieve the same thing with different notations. The first one is the object notation in JavaScript known mostly from JSON. There you’ve to construct a key/value pairs, divided by a colon:

var class1 = {
    a : 0,
    func1 : function() {
        console.log(class1.a);
    },
    func2 : function(a) {
        this.a = a;
    }
}
class1.func2(3);

Here we have two functions – func1 and func2 and one member variable. Func2 is setting up the member variable, it’s something like a setter in some languages like Java and PHP, and the func1 is printing the value of that variable via console.log(). Note that in the body of func1() the variable “a” is accessed with the class name: class1.a. Here the notation can be changed to this.a, which will result in the same thing.

...
console.log(this.a);
...

Notation #2

While in the notation I’ve just used is not possible to have two different instances from the same class, in the next example this is possible. In JavaScript the objects are even the functions, and you can access the function’s private variables with the dot notation.

var class2 = function() {
    this.a = 0;
    this.func1 = function() {
        console.log(this.a);
    }
 
    this.func2 = function(a) {
        this.a = a;
    }
}

To use this object you’ve to use the “new” operator.

var c = new class2();
c.func2(4);

This helps you create more than one instance of the same class.

var c = new class2();
var d = new class2();
c.func2(3);
d.func2(4);

Models in Zend Framework – Initialize All Methods with init()

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In the Zend Framework’s documentation there are lots of examples how you can initialize all the actions in a given controller – by simply adding the init() public method in the controller’s code:

<?php
 
class IndexController extends Zend_Controller_Action
{
	public function init()
	{
		echo 'foo';	
	}	
 
	public function indexAction()
	{
		// first the 'foo' string will be printed
		echo 'bar';	
	}
}

But did you know that you can do the same thing with any model in ZF? However you can setup a cache for every method or something else, but definitely it will execute for every method:

<?php
 
class MyModel
{
	public function init()
	{
		// prepare the cache setup
	}	
 
	public function readAll()
	{
		// the cache is already setup
		$sql = '...';
		// ...
	}
}

Of course that means that directly calling the readAll() function the init() method is called also – automatically.

Conclusion

There are good and bad parts about this. You’ll have this code executed for every method and if you have twenty of them and the init() method is practically used for only a couple of the member functions – than this will be useless.

Setting Up Zend Framework with Modules

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Typical Zend App

Typically you’ve one module in your Zend App – the default one. In the basic installation of the framework, you put all the controllers, models and views directly in the application folder, as described below.

/application
	- /controllers
		- /IndexController.php
	- /models
		- /MyModel.php
	- /views
		- /scripts
			- /index/index.phtml
/library
	- /Zend
/public_html
	- /images
	- /scripts

Bigger Apps – More Code

When the application becomes bigger and bigger the controller, models and views/scripts directories contain more and more files. That’s a bit odd, because it becomes difficult to maintain, and than the modules come in hand.

Modules in a Zend App

When it comes to setting up modular Zend App there are tons of articles in the web, but let me show you a simple directory layout and … sample code that sets up the framework.

/application
	- /modules
		+ /admin
			- /controllers
				- /IndexController.php
			- /views
				- /scripts
					- /index/index.phtml
		+ /default
			- /controllers
				- /IndexController.php
			- /views
				- /scripts
					- /index/index.phtml
	- /models
/library
	- /Zend
/public_html
	- /images
	- /scripts

Source

Simply add this into the bootstrap:

$frontController->addModuleDirectory(APPLICATION_PATH . '/modules');

Fetching Rows With Zend_Db fetch()

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Fetching the Entire Row Set

Rows

What is really handy in Zend Framework is that you can fetch the entire row set with the fetchAll() method. It comes with some parameters that you can use for limiting the result or ordering, but in general you can use it without specifying parameters. Let say this is the model:

<?php
class User extends Zend_Db_Table
{
 
	public function listAll()
	{
		$query = "SELECT * FROM user";
 
		// exec query
		$rs = $this->getAdapter()->query($query);
 
		return $rs->fetchAll();
 
	}
 
}

You can simply return the row set with the fetchAll() method as described in the example, but what if you have to loop through the rows and to modify somehow the values?

Fetching a Row

By simply change the code like so:

class User extends Zend_Db_Table
{
 
	public function listAll()
	{
		$query = "SELECT * FROM user";
 
		// exec query
		$rs = $this->getAdapter()->query($query);
 
		// fetch
		$list = array();
		while ($row = $rs->fetch()) {
			// removing the password column value
			$row['password'] = '';
 
		    $list[] = $row;
		}
 
		return $list;
	}
}

you can modify the rows and you’ll have the same result.

HTML Tags: <base>

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Overview

base

Somehow the <base> tag remains unknown to most of the web developers, but that’s quite normal. However let see what it can do. By adding the <base> tag in the head of the page you tell every link into that page how to open and a default href value. Thus if you have:

<base href="http://www.stoimen.com/blog/">

every link without a href attribute will open this link. That’s really useful in some cases. However the most interesting part of the base tag is the target attribute.

target=”_blank”

Everybody knows what will result from this attribute attached to a anchor tag.

<a href="http://www.stoimen.com" target="_blank">Click Here</a>

But with only adding this base tag:

<base target="_blank">

into the head … all the links will open in a new tab/window, depending on the browser preferences.

Watch out!

If you add the line above somewhere into the <body> tag the browser, will put it into the <head> which will make it difficult to track. A good practice is to place it directly into the <head>!