Web Systems and Technologies

Web Systems and Technologies

• Web Systems and Technologies are the tools, frameworks, protocols, and methodologies used to create, deploy, and manage web-based applications and services.
• It encompasses aspects of web development, from front-end interfaces to back-end systems.

Front-End Development

• Front-End technologies include HTML, CSS, JavaScript, and frameworks like React, Angular, and Vue.js.
• Its purpose is to create the User Interface (UI) and ensure a good user experience (UX) by making web pages responsive, accessible, and interactive.

Back-End Development

• Back-End technologies include Server-side languages like Python (Django, Flask), PHP (Laravel), Ruby (Rails), Java (Spring), and Node.js (Express).
• The purpose of this is handling business logic, database interactions, and server-side operations, including APIs, authentication, and data processing.

Databases

• Database technologies include SQL databases like MySQL and PostgreSQL and NoSQL databases like MongoDB and Redis.
• The purpose of databases is storing and managing data for web applications.

Web Servers

• Web servers include Apache, Nginx, and IIS.
• The purpose of a web server is serving web pages to users by processing incoming requests and delivering content.

Web Protocols

• Web protocols include HTTP/HTTPS, FTP, REST, SOAP, and WebSockets.
• The purpose of web protocols is governing how data is transmitted over the web, enabling communication between clients (browsers) and servers.

Content Management Systems (CMS)

• CMS examples include WordPress, Joomla, and Drupal.
• CMS's purpose is allowing users to manage and publish digital content without needing technical knowledge.

Web Hosting and Cloud Services

• Web hosting providers include AWS, Google Cloud, and Microsoft Azure.
• These services host websites and web applications, often providing scalable resources to handle varying traffic loads.

Security

• Security technologies include SSL/TLS, OAuth, encryption algorithms, and firewalls.
• These technologies protect web applications from threats like hacking and data breaches, ensuring secure transactions.

DevOps and Continuous Integration/Continuous Deployment (CI/CD)

• DevOps tools include Jenkins, Docker, Kubernetes, and Git.
• This streamlines development, testing, and deployment processes to improve efficiency and reduce errors.

Web Analytics and SEO

• Web analytics tools include Google Analytics, SEMrush, and Moz.
• Its purpose is monitoring web traffic, user behavior, and optimizing content for search engines to improve visibility.

Web Applications

• A Web Application is a program that runs on a web server and is accessed through a web browser over the Internet.
• Web applications are hosted on remote servers and delivered to users through the web, unlike traditional desktop applications.
• Examples of web applications include E-Commerce Platforms, Social Media Platforms, Content Management Systems (CMS), and Web-Based Email Clients.
• Further examples include Streaming Services, Collaboration and Productivity Tools, Online Learning Platforms and Cloud Storage Services.
• Others include Financial and Banking Applications and Entertainment and Media Platforms.

Current Trends and Technologies in Web

• Progressive Web Apps (PWA) combine the best of web and mobile apps.
• Single Page Applications (SPA) provide a seamless user experience using frameworks like Angular and React.
• Serverless Architecture includes AWS Lambda and Azure Functions.
• WebAssembly (Wasm) enables high-performance applications on the web.
• AI and Machine Learning Integration enhances user experience and personalization.
• Voice Search Optimization adapts websites for voice-based queries.
• Cybersecurity Measures increase focus on protecting web applications from threats.

PHP Basics

• PHP (Hypertext Preprocessor) is a widely-used, open-source, server-side scripting language suited for web development.
• It was created by Rasmus Lerdorf in 1994 and has become popular for creating dynamic and interactive websites.
• Key features of PHP include server-side scripting, embedded in HTML, cross-platform compatibility, database integration, extensive library and framework support, and open source.

How PHP Works

• A user interacts with a web page and their browser sends a request to the web server to load the page.
• The request may be for a PHP file, which contains PHP code.
• The web server receives the request and identifies that it needs to process a PHP file.
• The server passes the PHP file to the PHP engine for executing the code within the file.
• The PHP engine processes the PHP code which may interact with a database like MySQL to retrieve or store information.
• After processing, the PHP code generates an HTML file as the output.
• The web server sends the generated HTML file back to the user's web browser as a response, and the browser displays the content of the HTML file as a fully rendered web page.

PHP Installations

• Installing PHP depends on the operating system and web server you plan to use.
• XAMPP is a popular package that includes PHP, Apache (a web server), and MySQL (a database).

PHP Syntax

• PHP syntax is the set of rules that define how PHP code is written and structured.
• A PHP script is executed on the server, and the plain HTML result is sent to the browser.
• PHP scripts can be placed anywhere in the document.
• The default file extension for PHP files is ".php".
• PHP code is embedded within HTML and enclosed within special PHP tags .
• Everything between these tags is treated as PHP code and executed by the server.
• Each PHP statement ends with a semicolon (;).
• PHP variables are case-sensitive ($name and $Name are different), but function names are not.

PHP Variable

• A PHP variable is a container used to store and manipulate data in a PHP script.
• Variables in PHP are dynamic and can hold strings, numbers, arrays, and more.
• A variable starts with the $ sign, followed by the name of the variable.
• Variable names must start with a letter or the underscore character
• It cannot start with a number
• It can only contain alpha-numeric characters and underscores (A-z, 0-9, and _).
• Variable names are case-sensitive ($age and $AGE are two different variables).
• Every variable in PHP begins with a $ symbol.
• PHP is a loosely typed language, eliminating the need to declare a variable's type.

PHP Echo

• The echo statement in PHP is used to output data to the screen within a web page.
• It the most common and simplest ways to display content such as text, variables, and HTML code.
• The echo statement can be used to display text or variables with or without parentheses.
• Strings can be directly outputted using echo.
• The echo statement can be used to display the value of a variable.
• Concatenation, done using the . operator, joins multiple strings and variables together.
• echo can output HTML code, which renders within the browser.
• echo can accept multiple parameters, separated by commas, although this is less commonly used.
• echo is faster than print because it doesn't return a value. While print always returns 1, echo simply outputs content and continues with the script.

PHP Data Types

• PHP data types refer to the kinds of values that variables can hold.
• PHP supports scalar, compound, and special types of data.
• Scalar data types are the simplest; they represent a single value.
• A string is a sequence of characters enclosed in single (') or double (") quotes.
• An integer is a non-decimal number, either positive or negative.
• A float is a number with a decimal point or exponential form.
• A boolean represents a value of either true or false.
• Compound data types can hold multiple values.
• An array is a collection of values; each can be of any data type and is accessed via an index or key.
• An object is an instance of a class, allowing complex data structures that model real-world entities.
• Special Data Types handle special cases.
• NULL represents a variable with no value and is the only possible value of this type.
• A resource is a special type that holds a reference to an external resource, such as a database connection or file handler.

PHP Superglobals

• PHP superglobals are built-in global arrays that are always accessible, regardless of scope.
• These variables are useful because they allow you to retrieve or pass data in your PHP applications.
• $_GET contains data sent to the script via URL parameters (query strings).
• $_POST contains data sent to the script via an HTML form using the POST method.
• $_REQUEST contains data sent to the script via $_GET, $_POST, and $_COOKIE.
• $_FILES contains information about files uploaded to the script via an HTML form using the POST method with enctype="multipart/form-data".
• $_COOKIE contains data sent to the script via HTTP cookies. Cookies are small pieces of data stored client-side and sent to the server with every request.
• $_SESSION contains data related to a user session. Sessions are used to store information across multiple pages/requests.
• $_SERVER contains information about the server environment and the client request, including data such as headers, paths, and script locations.
• $_ENV contains data related to the environment in which the script is running. Environment variables are often in the server configuration or OS.
• $_GLOBALS contains all global variables in the script and allows accessing them from any scope.