All posts by Pramod T P

Object Oriented Concepts

Class: This is a programmer-defined datatype, which includes local functions as well as local data. You can think of a class as a template for making many instances of the same kind (or class) of object.

Object: An individual instance of the data structure defined by a class. You define a class once and then make many objects that belong to it. Objects are also known as instance.

Member Variable: These are the variables defined inside a class. This data will be invisible to the outside of the class and can be accessed via member functions. These variables are called attribute of the object once an object is created.

Member function: These are the function defined inside a class and are used to access object data.

Inheritance: When a class is defined by inheriting existing function of a parent class then it is called inheritance. Here child class will inherit all or few member functions and variables of a parent class.

Parent class: A class that is inherited from by another class. This is also called a base class or super class.

Child Class: A class that inherits from another class. This is also called a subclass or derived class.

Polymorphism: This is an object oriented concept where same function can be used for different purposes. For example function name will remain same but it make take different number of arguments and can do different task.

Overloading: a type of polymorphism in which some or all of operators have different implementations depending on the types of their arguments. Similarly functions can also be overloaded with different implementation.

Data Abstraction: Any representation of data in which the implementation details are hidden (abstracted).

Encapsulation: refers to a concept where we encapsulate all the data and member functions together to form an object.

Constructor: refers to a special type of function which will be called automatically whenever there is an object formation from a class.

Destructors: refers to a special type of function which will be called automatically whenever an object is deleted or goes out of scope.



nginx [engine x] is an HTTP and reverse proxy server, a mail proxy server, and a generic TCP proxy server, originally written by Igor Sysoev. For a long time, it has been running on many heavily loaded Russian sites including Yandex, Mail.Ru, VK, and Rambler. According to Netcraft, nginx served or proxied 21.64% busiest sites in May 2015.

Nginx (pronounced engine-x) is a free, open-source, high-performance HTTP server and reverse proxy, as well as an IMAP/POP3 proxy server. Igor Sysoev started development of Nginx in 2002, with the first public release in 2004. Nginx now hosts nearly 12.18% (22.2M) of active sites across all domains. Nginx is known for its high performance, stability, rich feature set, simple configuration, and low resource consumption.

Nginx is one of a handful of servers written to address the C10K problem. Unlike traditional servers, Nginx doesn’t rely on threads to handle requests. Instead it uses a much more scalable event-driven (asynchronous) architecture. This architecture uses small, but more importantly, predictable amounts of memory under load.
Even if you don’t expect to handle thousands of simultaneous requests, you can still benefit from Nginx’s high-performance and small memory footprint. Nginx scales in all directions: from the smallest VPS all the way up to clusters of servers.



Encapsulation is the packing of data and functions into a single component. The features of encapsulation are supported using classes in most object-oriented programming languages, although other alternatives also exist.


Abstract Classes

PHP 5 introduces abstract classes and methods. Classes defined as abstract may not be instantiated, and any class that contains at least one abstract method must also be abstract. Methods defined as abstract simply declare the method’s signature – they cannot define the implementation.

When inheriting from an abstract class, all methods marked abstract in the parent’s class declaration must be defined by the child; additionally, these methods must be defined with the same (or a less restricted) visibility. For example, if the abstract method is defined as protected, the function implementation must be defined as either protected or public, but not private. Furthermore the signatures of the methods must match, i.e. the type hints and the number of required arguments must be the same. For example, if the child class defines an optional argument, where the abstract method’s signature does not, there is no conflict in the signature.



A is special method of the class that will be automatically invoked when an instance of the class is created is called as constructor.

Constructors are mainly used to initialize private fields of the class while creating an instance for the class.

When you are not creating a constructor in the class, then compiler will automatically create a default constructor in the class that initializes all numeric fields in the class to zero and all string and object fields to null.

Types of Constructors

  • Default Constructor
  • Parameterized Constructor
  • Copy Constructor
  • Static Constructor
  • Private Constructor


Magento is an e-commerce platform created on open source technology, which provides online merchants with an exceptional flexibility and control over the content, look and functionality of their e-commerce store.

Magento is an open-source content management system for e-commerce web sites. The software was originally developed by Varien Inc., a US private company headquartered in Culver City, California, with assistance from volunteers.

Varien published the first general-availability release of the software on March 31, 2008, under the name Bento. Roy Rubin, former CEO of Varien, later sold a substantial share of the company to eBay, which is now the sole owner.

According to research conducted by aheadWorks in October 2014, Magento’s market share among the 30 most popular e-commerce platforms is about 30%.

Magento employs the MySQL relational database management system, the PHP programming language, and elements of the Zend Framework. It applies the conventions of object-oriented programming and model-view-controller architecture. Magento also uses the entity–attribute–value model to store data.


Persistent Cookie

Also called a permanent cookie, or a stored cookie, a cookie that is stored on a user s hard drive until it expires (persistent cookies are set with expiration dates) or until the user deletes the cookie.

Persistent cookies help websites remember your information and settings when you visit them in the future. This result in faster and more convenient access since, for example, you don’t have to login again.

Besides authentication, other website features made possible by persistent cookies include: language selection, theme selection, menu preferences, internal site bookmarks or favorites, among many others. On your first visit, the website is presented in default mode. During your visit, you select your preferences and these preferences are remembered, through the use of the persistent cookie, the next time you visit the site.