Prevent Your CSS and JavaScript Files From Being Cached

Some websites use highly volatile, oft-changing CSS and JavaScript files. In the case of these files, it’s important that the developer prevent browsers from caching them. How do we do that? By using a phantom querystring, of course. We’ll use PHP to tack the current time onto the file reference.

The PHP

<link href="/stylesheet.css?<?php echo time(); ?>" rel="stylesheet" type="text/css" >
<-- RENDERS -->
<link href="/stylesheet.css?1234567890" rel="stylesheet" type="text/css">

<script type="text/javascript" src="/site-script.js?<?php echo time(); ?>"></script>
<-- RENDERS -->
<script type="text/javascript" src="/site-script.js?1234567890"></script>

It’s a very simple technique and doesn’t affect your CSS or JavaScript code in any way.

Resource :

http://davidwalsh.name/prevent-cache

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Android Detection with JavaScript or PHP

Hello Friends

You have a web application and you want to detect that if your Application is opened from android device than it will be redirect to any other URL that will be Android compatible.This is a good solution for you.

What’s obvious is that Android development is a hot topic that will only grow. Here are a few methods by which you can detect iOS‘ main competitor: Android.

The JavaScript

Searching the user agent string for “Android” is the quickest method:

var ua = navigator.userAgent.toLowerCase();
var isAndroid = ua.indexOf("android") > -1; //&& ua.indexOf("mobile");
if(isAndroid)
{
// Do something! // Redirect to Android-site? window.location = 'http://android.viralsolani.co';
}

The PHP

Again, we’ll use PHP’s strstr function to search for Android in the user agent:

$ua = strtolower($_SERVER['HTTP_USER_AGENT']);
if(stripos($ua,'android') !== false){// && stripos($ua,'mobile') !== false) {
header('Location: http://android.viralsolani.co');
exit();
}

Bonus! .htaccess Detection

We can even use .htaccess directives to detect and react to Android devices!

RewriteCond %{HTTP_USER_AGENT} ^.*Android.*$
 RewriteRule ^(.*)$ http://android.viralsolani.co [R=301]

And there you have it: three different Android device detection! Have fun with your mobile development!

Resource :

http://davidwalsh.name/detect-android

Thanks

 

How to install SSL Certificates with Apache 2 on Ubuntu 12.04

Please note that commercial SSL certificates require a unique IP address each for SSL-enabled site, although multiple non-SSL sites may also share that IP address.

Step – 1 Create a Certificate Signing Request

A CSR is an encrypted body of text. Your CSR will contain encoded information specific to your company and domain name; this information is known as a Distinguished Name or DN.
In the DN for most servers are the following fields: Country, State (or Province), Locality (or City), Organization, Organizational Unit, and Common Name. Please note:
1. The Country is a two-digit code — for the United States, it’s ‘US’. For countries outside of the United States,
2. State and Locality are full names, i.e. ‘California’, ‘Los Angeles’.
3. The Organization Name is your Full Legal Company or Personal Name, as legally registered in your locality.
4. The Organizational Unit is whichever branch of your company is ordering the certificate such as accounting, marketing, etc.
5. The Common Name is the Fully Qualified Domain Name (FQDN) for which you are requesting the ssl certificate.
If you are generating a CSR for a Wildcard Certificate your common name must start with *. (for example: *.digicert.com). The wildcard character (*) will be able to assume any name that does not have a “dot” character in it.
To remain secure, certificates must use keys which are at least 2048 bits in length. If your server platform can’t generate a CSR with a 2048-bit key

mkdir /etc/apache2/ssl
 cd /etc/apache2/ssl
 openssl req -new -newkey rsa:2048 -nodes -keyout yourdomain.key -out yourdomain.csr

Replace yourdomain with the domain name you’re securing. For example, if your domain name is viralsolani.co, you would type viralsolani.co.key and viralsolani.co.csr.

• This begins the process of generating two files: the Private-Key file for the decryption of your SSL Certificate, and a certificate signing request (CSR) file (used to apply for your SSL Certificate) with apache openssl.

• Open the CSR file with a text editor and copy and paste it (including the BEGIN and END tags) into the form from where you purchase your SSL certificate.

• Save (backup) the generated .key file as it will be required later for Certificate installation

Execute the following command to protect the key:
chmod 400 /etc/apache2/ssl/www.yourdomain.com.key

Execute the following command to protect the signed certificate:

chmod 400 /etc/apache2/ssl/www.mydomain.com.crt

Step – 2 Get the Certificate Authority Root Certificate
In My case it is Go Daddy. So you need to go from wherever you purchase your SSL certificate and you need to submit the below generated CSR. And you can then download the certificate.
You will get two files. I’ve upload that two files in same folder where I’ve put my CSR and Private key that i.e /etc/apache2/ssl/
Step – 3 Configure Apache to use the Signed SSL Certificate.

This configuration vary depend upon OS and version of that OS. So I’ve installed Ubuntu 12.04 and to configure the certificate you need to do below steps.
You need to configuration in Apache virtual hosting file.
So now you need to go: /etc/apache2/sites-available/default-ssl

<IfModule mod_ssl.c>
<VirtualHost _default_:443>
ServerAdmin viral.solani@gmail.com

DocumentRoot /var/www
<Directory />
Options FollowSymLinks
AllowOverride None
</Directory>
<Directory /var/www/>
Options Indexes FollowSymLinks MultiViews
AllowOverride None
Order allow,deny
allow from all
</Directory>

SSLCertificateFile    /etc/apache2/ssl/yourdomain.com.crt
SSLCertificateKeyFile /etc/apache2/ssl/yourdomain.com.key
SSLCertificateChainFile /etc/apache2/ssl/gd_bundle.crt

</VirtualHost>
</IfModule>

Basically you need to locate yourdomain.com.crt , yourdomain.com.key and gd_bundle.crt.
Now last thing you need to do is restart you apache with the following command

 /etc/init.d/apache2 restart

You should now be able to visit your site with SSL enabled. Congratulations, you’ve installed a commercial SSL certificate!

Understanding Abstract Classes in PHP

Abstract classes are an often misunderstood feature of PHP object-oriented programming (OOP) and the source of confusion when considered versus an Interface. The obvious reason for using an Interface is that a child class can implement multiple interfaces but extend only a single abstract class. However, if multiple inheritance is not required then people often go with abstract classes just because they provide the option of later adding base functionality within the abstract class. This is not entirely unreasonable but the reasons for creating abstract classes should be more than that.
Why Use Abstract Classes?

An Abstract class provides concrete base functions as well as abstract functions that must be implemented by concrete child classes—binding them into a contract so to speak, if they wish to make use of the base functionality.

This is a subtle but important point and this is where abstract classes really shine. They can call abstract functions from within base concrete functions. Jumping straight to an example is the clearest way to explain this.

abstract class Animal {
  function greeting() {
    $sound = $this->sound();      // exists in child class by contract
    return strtoupper($sound);
  }
  abstract function sound();      // this is the contract
}

class Dog extends Animal {
  function sound() {              // concrete implementation is mandatory
    return "Woof!";
  }
}

$dog = new Dog();
echo $dog->greeting();            // WOOF!

This opens up a whole lot of interesting possibilities. For example, you can write a drive() function that calls $this->start(); $this->accelerate(); in an abstract class. Then create a motorcycle class that defines its own start() and accelerate() functions that may be different from those in the car class. In turn, the motorcycle and car can both be driven by just calling drive() without having to implement it locally.
Characteristics of Abstract Classes

Make a note of these characteristics to lock down your understanding of abstract classes:

  • Single inheritance. Child classes can extend only one class at a time.
  • Abstract classes cannot be instantiated — no new Animal();
  • Abstract classes can define class variables of type const only.
  • Abstract class A can be extended by another abstract class B. Abstract class B can implement none or any of the abstract functions in A.
  • In the previous case, a child class C which extends abstract class B must implement all abstract functions in B as well as the abstract functions in A which have not already been implemented in B.
  • The signature of the concrete functions and abstract functions must be the same. However, if an abstract function is defined as abstract function speak($greeting); then it is okay to implement it as function speak($greeting, $shout = FALSE) but not function speak($greeting, $shout).
  • The visibility of functions in the child classes must be the same or less restrictive than the parent class. Thus, a protected abstract function can be implemented as either protected or public but not private.
  • Declaring functions as static abstract throws a strict warning in PHP 5.2 or earlier, however, as of PHP 5.3 this is allowed.

Superb way of adding PHP variables to Javascript/Jquery in Zend Framework

Rupesh Patel Web Developer

If you are using any MVC framework(these days I think most of us uses MVC) in php, then you might needed to assign variables from php to javascript, Some times you might have to add tens of parameters to javascript. And this thing leads to dirty code like below in any of your view files..

and the main problem with this solution is you have to do it explicitly for each of variables. And What if you want to add an array to javascript ?

I have done some thing interesting to cop this in Zend Framework , Similar can be done in any of MVC systems if views and control code is differentiated.

1) Create a view file at application/views/index/include_js_vars.phtml  and paste following code in this file.

2) now most probably you are including java scripts in your layout file application/layouts/scripts/layout.phtml
so render our include_js_vars view before [ echo…

View original post 124 more words

Nice Story……

2Motivate

There was a king who was a great admirer of art. He encouraged artists from all over his country and gave them valuable gifts.

One day an artist came and said to the king, “Oh King! Give me a blank wall in your palace and let me paint a picture on it. It will be more beautiful than anything you have ever seen before. I promise you shall not be disappointed.” Now, the king happened to be constructing a big hall at the rear end of the palace. So he said, “All right you may work on one of the walls in the new hall.”

So the artist was given the job and he was very pleased indeed. Just then, another young man said, “Oh King! Please allow me to work on the opposite wall. I too am an artist.”

The king said, “What would you like to make?”

The…

View original post 448 more words