BACK-END TECHNOLOGIES

Crafting beauty behind the scenes

Do you want a smart kid, who also wins all the beauty pageants? That’s the type of products we code at Codezilla.

Without an effective and efficient back-end web development, your customer can not have a good experience on your website or App.The utility and user experience of a website or App effect its popularity in the distant future. The back-end of your web or Mobile application is the thing that enables a front-end experience for your user. You can have a stunning webpage, but if the application doesn’t work, then the whole thing will end up being a failure.



Want a smoother, faster, classier backend, what would beat the absolute classiness of Node?


    Some benefits of using Node js :
  • Good for beginner developers, JavaScript is simple to learn, rich framework (Angular, Node, Backbone, Ember)
  • It is fast, due to Google innovative technologies and the event loop
  • Ability to keep data in native JSON (object notation) format in your database
  • Multiple modules (NPM, Grunt, etc.) and supportive community
  • Good to create real-time apps, such as chats and games
  • Single free codebase
  • Good for data streaming, thus for audio and video files, as example
  • Sponsored by Linux Foundation, as well as PayPal, Joylent, Microsoft, Walmart
  • Wide range of hosting options
  • JS is the longest running language, 99% of developers know some of it.


Node.js is server-side scripting based on Google’s V8 JavaScript engine. It is used to build scalable programs, especially web applications that are computationally simple but are frequently accessed. You can use Node.js in developing I/O intensive web applications like video streaming sites. You can also use it for developing: Real-time web applications, Network applications, General-purpose applications, and Distributed systems.

    Node.js makes building scalable network programs easy. Some of its advantages include:
  • It is generally fast
  • It almost never blocks
  • It offers a unified programming language and data type
  • Everything is asynchronous
  • It yields great concurrency

Node.js is a single-threaded but highly scalable system that utilizes JavaScript as its scripting language. It uses asynchronous, event-driven I/O instead of separate processes or threads. It can achieve high output via single-threaded event loop and non-blocking I/O.

Node.js is single-threaded for async processing. By doing async processing on a single-thread under typical web loads, more performance and scalability can be achieved as opposed to the typical thread-based implementation.

A callback function is called after a given task. It allows other code to be run in the meantime and prevents any blocking. Being an asynchronous platform, Node.js heavily relies on callback. All APIs of Node are written to support callbacks. Explain the role of REPL in Node.js. As the name suggests, REPL (Read Eval Print Loop) performs the tasks of – Read, Evaluate, Print and Loop. The REPL in Node.js is used to execute ad-hoc Javascript statements. The REPL shell allows entry to javascript directly into a shell prompt and evaluates the results. For the purpose of testing, debugging, or experimenting, REPL is very critical.

NPM (Node Package Manager) provides two functionalities: An online repository for Node.js packages. Command-line utility for installing packages, version management and dependency management of Node.js packages.

Node.js and Ajax (Asynchronous JavaScript and XML) are the advanced implementations of JavaScript. They all serve entirely different purposes.
Ajax is primarily designed for dynamically updating a particular section of a page’s content, without having to update the entire page.
Node.js is used for developing client-server applications.

Explain chaining in Node.js.Chaining is a mechanism whereby the output of one stream is connected to another stream creating a chain of multiple stream operations.


Startup friendly, flexible, well-supported


Utilizing the best technologies for the website development helps the developers to make remarkable changes in a small business venture. Ruby on rails development is one of the best examples of adding value and productive standards to web development. The recent popularity of Ruby on Rails (ROR) technology is a response to the endless advantages to the customers for the finished products. The developers can enjoy effortless developing process by using ROR development services.



Ruby is a programming language, and Ruby lon Rails is its web application development framework. A web framework’s job is to support web app development and establish a standard way of building web projects. Rails provides components like an ORM (Object Relational Mapping) system for business data and logic, routing, and application management out of the box.

To understand the answer, let’s first establish that a backend usually has three parts: a server, an application, and a database. These are all the elements users don’t see or interact with directly. Ruby and Rails are mainly backend technologies, used to create and fine-tune the inner workings of an app, its data storage, and architecture. In web development, the popular frontend language is JavaScript. But Ruby on Rails is a complete web development framework. It includes frontend code and HTML views, so it’s possible to create all necessary frontend assets with it. RoR is an all-in-one web solution.

Ruby is often listed as the language that allows for the fastest development. This speed can be achieved thanks to gems – libraries built to deliver specific functionalities, such as authentication and authorisation, testing, or payment processing. As these are solutions that have already been written, Rails developers can often use them wholesale for their apps, focusing on adjusting the app’s architecture and making sure everything works well together, but avoiding writing solutions that have already been written a thousand times. Unless your app’s log-in functionality is somehow unique, there’s no reason to write it from scratch. A good RoR developer knows this, and picks the right gem to avoid reinventing the wheel. Working with a bigger, experienced RoR team is also a good idea – they usually have established practices and recommended gems, which can significantly speed up their work.

As already mentioned, one of Rails’ main advantages is its development speed. That’s why the framework can be a perfect fit for many startups, growing companies and entrepreneurial projects within larger businesses. Almost any web project can benefit from Ruby’s speed of development, high industry standards, and a robust community, which provides fantastic pre-built solutions. RoR works well for SaaS projects thanks to the framework’s good performance, security, flexibility, and scalability. It’s a popular choice for ecommerce platforms for the same reasons and the additional benefits of good payment integrations and ease of deployment. It might actually be easier to define projects that would be better served by other languages and frameworks. These include: apps built to support heavy calculations; high-performance, near-real time services; most Machine Learning apps.

The most important advantages of building apps with Ruby on Rails include speed of development, a robust community, and top industry standards introduced by the framework.
As already mentioned, Rails comes with a number of gems, and allows for a modular approach to development. Your team can focus on creating the most efficient architecture for your app, without wasting time on writing code that’s already been written many, many times.
RoR was created with the high velocity of prototyping and application development in mind. Its well-developed system of modules, generator scripts, and an efficient package management system allow scaffolding a complex application in just a few commands.
Ruby is also an expressive, concise language that allows developers to achieve more in fewer lines of code.
RoR’s second big advantage is its flourishing, mature community, providing solutions, resources, and advice. These proactive developers are the ones responsible for the creation of many Ruby gems. They also make sure that Rails is regularly updated, secure and up-to-date with industry standards.
Ruby on Rails is an opinionated framework – using it comes with a bit of guidance, leading developers to doing things the Rails way: using best standards and practices of web development.

Now for some disadvantages :
  • If your main focus for the project is its runtime speed, Node.js or Django might serve you better.
  • Additionally, RoR comes with some hard dependencies and modules out of the box. These might be unnecessary if your app is particularly unique (e.g. if you need custom routing or database migrations), and your developers might have a difficult time shaping RoR to the project’s needs.
  • Finally, because prototyping with Rails is so incredibly fast, bad architectural choices early on in the development might be pretty costly, affecting your app’s performance and even requiring a full refactoring of your code.
  • Always make sure to work with a team of experienced Ruby on Rails development company to avoid this.

Short answer: yes. Long answer: Ruby on Rails presents many advantages to startups. One of them is Rails’ large and vibrant developer community, which produces useful resources and is always ready to help your team out when they get stuck. RoR is a complete framework, used by many companies for commercial projects, and it’s constantly being improved. It’s easy to build a product with Rails, using the community resources and support. Development is also extremely fast, which is perfect for fast delivery or building an MVP and validating product goals. Clear-cut best practices make it faster and easier to write and debug code. All of these are great reasons to use RoR for a startup project.

Ruby on Rails can be a great tool for building an ecommerce project. In fact, it has often been technology of choice. With its ecommerce framework, Spree, Rails offers all the necessary functionalities, along with a mature codebase, ready-to-use feature packages, easy payment integrations, a well-documented admin dashboard, and easy deployment.

Machine Learning allows computers to learn through interacting with data.

It’s useful for solutions such as recommendations based on user interests and past behaviours, and has become important for services like Netflix, Amazon or Facebook. Ruby, while it’s an elegant and mature programming language, doesn’t really compete in the speed of complex calculations category.
If you're looking for the right technology for an ML project, consider using a microservice written in a different language, e.g. Python, and connecting it to your Rail web app.

Listing all of them would take a ridiculously long time, so let’s focus on some of the biggest players. Airbnb, the popular travel lodging listing platform, users RoR. So does CrunchBase, the “Wikipedia of startups”, using RoR for its backend.
Other examples include GitHub (web hosting for software projects), Soundcloud (music platform), Zendesk (customer relations management service), Kickstarter (the most popular crowdfunding platform), Shopify (one of the biggest ecommerce platforms) and Twitch (popular online video broadcasting service).

It’s not difficult, but there are a few important things you will need to pay attention to. Choosing the right Ruby on Rails development team matters, because using RoR to its full advantage requires a lot of experience.
Because the framework comes with so many games and solutions, and because of its opinionated nature, it isn't always easy to make the right decisions for a given project.
First of all, choose a team of developers rather than a single freelancer: they’ll have much more know-how and will be able to solve each other’s problems.

    Pay attention to their development process:
  • Do they use Agile practices and provide effective channels of communication?
  • Do they offer testing and QA?
Next, ask them about their tools. GitHub and CircleCI are some of the best options out there for code repository and continuous integration, respectively.


For Best Business Growth And Exceptional User Experience


PHP programming language is one of the best choices for small as well as big software organizations for rapid prototyping and development of both static and dynamic websites. As per recent research right now 82 % of the websites on the internet are powered by PHP language. You may also know that the popular social platforms like Facebook, Tumblr, Wikipedia, and Flickr are also powered by PHP language. Yahoo search engine is also based on PHP. Also popular opensource content management system (CMS) like WordPress, Joomla and Drupal are also based on PHP language. WordPress holds more than 25% of all the websites in CMS market and is powered by PHP. It speaks about PHP success itself. PHP's superb compatibility with other technologies, open-source, dynamic and interactive nature, universal browser support and database integration are some of the features that make it the most preferred programming language. It allows the developers to create engaging web applications with the least investment of resources and time.



PHP is a server-side scripting language which is used to create dynamic web pages.

Rasmus Lerdorf
The language is used to Implementation is C/C++

PHP Version: 7.0.6 Dated April 29, 2016.
Official Website: http://php.net/

.php, .phtml, .php4, .php3, .php5, .phps

works in following flow
  1. Open website: http://www.web-technology-experts-notes.in/
  2. Request send on server of: http://www.web-technology-experts-notes.in/
  3. Call PHP Files.
  4. PHP Scripts are loaded into memory and compiled into Zend opcode.
  5. These opcodes are executed and the HTML generated.
  6. Same HTML is send back to Browser.

PHP function start with "function function-name()". PHP Function name must be start with character and it accept alphanumeric and _.
In build functions are case in-sensitive.
User build functions are case sensitive.
We can pass upto 64 parameter as argument.
Anonymous function are user defined function which have "no-name" and also called closures.
PHP support variable functions. Means when you can call a function using variable.
In same file OR under same class, same function name can't be created.

htmlentities is used to convert all applicable characters to HTML entities.
It is used to stop the user from running malicious code in HTML.
With use of htmlentities, user can't run the html tags like h2, p, script etc. It helps to prevent you from XSS attack.
echo htmlentities($userData);

  • Email functionality is inbuilt with PHP.
  • PHP provide mail() with use of this, we can sen an email to user or subscriber.
  • We can send html/text email.
  • We can send attachment with email.
  • We can also use option like cc, bc and bcc.
  • We can also set the values in header.
  • We can also use third party API like (gmail, yahoo etc) to send email.
  • Create an session in PHP.
  • Session data is stored in Server.
  • Session data have unique name.
  • Session unique key with domain name is stored in browser cookie.
  • Now, Browser keep the login with use of unique key(in cookie) and session data (stored in server side).
  • What is the difference between the functions unlink and unset?
  • Unlink: delete the files from Server.
  • unset: delete the variable name and data from memory.

With use virtual host and htaccess, you can create sub domain.

  • $_COOKIE – Stored information in Cookie.
  • $_GET – Send data in URL as paramter.
  • $_POST – Send data to server OR Page as POST Method.
  • $_REQUEST – Its combined array containing values from the $_GET, $_POST and $_COOKIES.
  • $_ENV – Get/Set varaible in environment.
  • $_FILES – Used to upload the file, image and videos etc.
  • $_SERVER – It have all server information.
  • $GLOBALS – Contains all the global variables associated with the current script.

echo $_SESSION['REMOTE_ADDR'];

Single inheritance.
Multiple Level inheritance.

CMS means Content Management System. It is web software who provide the website full fledged content management where owner can add/update/delete the html/files/images/videos etc. Today's CMS do much more as compare to its name.
For example. Joomla/Wordpress is CMS but you can create E-commererce website and can accpet all types of payment.
In Today's CMS, you can create many different types of website like Ecommerce website, Personal blogging and Forum etc.

echo md5(uniqid(rand(), true));

echo constructor which is used to display the value in browser.
print is function which is used to display and return the value.


A powerful, flexible, & dynamic scripting programming language.


When you sit down to pick the right programming language for your business, you may be overwhelmed as it is quite a task. There are certain things that have to be taken into consideration like the cost, application security, user-friendliness, etc.before choosing the correct program. One of the most commonly used platforms is Python, which is an established one sure to bring lots of benefits for your business. Another perk of using Python is that it allows you for future upgrades and can also easily interact with other programming languages. Many websites use Python currently making it one of the most used programming languages in the world today.



# Criteria Java Python
1 Ease to use : Good Very Good
2 Speed of coding : Android 7.0 – 7.1.2 Nougat
3 Data Type : Static typed Dynamically typed
4 Data Science & machine learning applications : Average Very Good

Python is a high-level, interpreted, interactive, and object-oriented scripting language. Python is designed to be highly readable. It uses English keywords frequently, whereas other languages use punctuation, and it has fewer syntactical constructions than other languages.

  • Python is an interpreted language, so it doesn’t need to be compiled before execution unlike languages like C.
  • Python is dynamically typed, so there is no need to declare a variable with the data type. Python Interpreter will identify the data type on the basis of the value of the variable.
  • Python follows object-oriented programming paradigm with the exception of having access specifiers. Other than access specifiers (public and private keywords), Python has classes, inheritance, and all other usual OOPs concepts.
  • Python is a cross-platform language which means that a Python program written on a Windows system will also run on a Linux system with little or no modifications at all.
  • Python is literally a general-purpose language which means that Python finds its way in various domains such as Web Application Development, Automation, Data Science, Machine Learning, and more.

PYTHONPATH has a role similar to PATH. This variable tells Python Interpreter where to locate the module files imported into a program. It should include Python source library directory and the directories containing Python source code. PYTHONPATH is sometimes preset by Python Installer.

  • PYTHONSTARTUP: It contains the path of an initialization file containing Python source code. It is executed every time you start the interpreter. It is named as .pythonrc.py in Unix, and it contains commands that load utilities or modify PYTHONPATH.
  • PYTHONSTARTUP: It is used in Windows to instruct Python to find the first case-insensitive match in an import statement. Set this variable with any value to activate it.
  • PYTHONSTARTUP: It is an alternative module search path. It is usually embedded in PYTHONSTARTUP or PYTHONPATH directories to make switching of module libraries easy.
    Python has five standard data types:
  • Numbers
  • Strings
  • Lists
  • Tuples
  • Dictionaries

To access an element from ordered sequences, we simply use the index of the element, which is the number of the position of that element. The index usually starts from 0, meaning that the first element has the index 0 and the second has 1, and so on.
When we use the index to access elements from the end of a list, it’s called reverse indexing. In reverse indexing, the indexing of elements starts from the last element with the index number being ‘−1’. The second last element has the index ‘−2’, and so on. These indexes used in reverse indexing are called negative indexes.

Pickling is the process of converting Python objects such as lists, dicts, etc. into a character stream. This is done using a module named pickle, hence the name pickling.
The process of retrieving the original Python object from the stored string representation, which is the reverse of the pickling process, is called unpickling.

The map() function in Python has two parameters, function and iterable. The map() function takes a function as an argument and then applies that function to all the elements of an iterable, passed to it as another argument. It returns an object list of results.

Tkinter is an inbuilt Python module that is used to create GUI applications. It’s Python’s standard toolkit for GUI development. Tkinter comes with Python, so there is no installation needed. We can start using it by importing it in our script.

Python does follow an object-oriented programming paradigm and has all the basic OOPs concepts such as inheritance, polymorphism, and more, with the exception of access specifiers. Python doesn’t support strong encapsulation (adding private keyword before data members) although it does have a convention that can be used for data hiding, i.e., prefixing data member with two underscores.

Lambda function is an anonymous function (functions that don’t have names) in Python. To define anonymous functions, we use the lambda keyword instead of the def keyword, hence the name ‘lambda function’. Lambda functions can have any number of arguments but can have only one statement.

Self-keyword is used as the first parameter of a function inside a class that represents the instance of the class. The object or the instance of the class is automatically passed to the method that it belongs to and is received in the ‘self-keyword’. Users can use another name for the first parameter of the function that catches the object of the class, but it is recommended to use the self-keyword only as it is more of a Python convention.

Control flow statements are used to manipulate or change the execution flow of a program. Generally, the flow of execution of a program runs from top to bottom, but certain statements in Python can break this top to bottom order of execution. Control flow statements include decision-making, looping, and more.