Introduction to Web Technologies and Architecture

Web Fundamentals

  • Hypertext: Text containing links to other texts.
  • Hypermedia: Extension of hypertext including non-linear media like graphics, audio, and video.
  • Webpage: Single document with a unique URL viewed via a browser.
  • Website: Collection of related webpages under a single domain name.
  • Web Server: Hardware and software responding to client requests over the Web.

Protocols and Addressing

  • URL (Uniform Resource Locator): Human-readable address for a specific resource.
  • URI (Uniform Resource Identifier): Superset of URLs used to identify any resource (not exclusively on the internet).
  • IP Address: Numerical label assigned to devices (e.g., 192.0.2.1192.0.2.1 or 124.45.56.67124.45.56.67).
  • DNS (Domain Name System): Translates human-readable domain names into numerical IP addresses.
  • HTTP/HTTPS: HyperText Transfer Protocol (and its Secure version) for transmitting hypermedia documents like HTML.
  • TCP/IP: Governing protocol suite for Internet communication; HTTP typically uses Port 8080.

History of the Web

  • 1941: Jorge Luis Borges - "The Garden of Forking Paths".
  • 1945: Vannevar Bush - "As We May Think" (The Memex).
  • 1965: Ted Nelson - The Xanadu project.
  • 1968: Douglas Engelbart - NLS.
  • 1987: Apple - Hypercard.
  • 1990: Tim Berners-Lee @ CERN - World Wide Web.

Application Architecture and Standards

  • Frontend: Client-side interaction using HTML (Structure), CSS (Presentation), and JavaScript (Behavior).
  • Backend: Server-side logic including Web Servers, Application logic (PHP, Python, Java, etc.), and Databases (MySQL, MongoDB).
  • Full Stack: Management of all development phases: browser, server, and database.
  • HTML DOM: Document Object Model; a tree structure for representing and interacting with HTML objects.
  • Standards Bodies:     * W3C: International standards for WWW technologies.     * IETF: Develops Internet protocols (e.g., TCP/IP).     * Ecma: Standards for information systems (e.g., ECMAScript/JavaScript).

Mobile Web

  • Characteristics: Portable, personal, always connected, and sensor-rich (GPS, Accelerometer, etc.).
  • Native Applications: Platform-specific (iOS, Android); access full hardware but involve repetitive development cycles.
  • Web Applications: Delivered via browser; run on any device but have limited hardware access.
  • Hybrid Frameworks: Wrappers like PhoneGap / Cordova, Ionic, and React Native that provide native API access to web apps.

Web Security

  • Common Attacks:     * DoS/DDoS: Denial of service.     * XSS: Malicious script injection.     * SQL Injection: Database attacks via SQL code manipulation.     * Phishing: Masquerading as a trustworthy entity.
  • Key Concepts: Authentication (identity), Authorization (permissions), Confidentiality (secrecy), and Data Integrity (accuracy).

Data and Future Trends

  • IoT & WoT: Internet of Things connects physical items to the internet; Web of Things integrates them into the WWW via APIs.
  • Web of Data: Structuring data for machine readability (Semantic Web) using standards like RDF and OWL.
  • Web Evolution:     * Web 1.0: Catalogs, static HTML.     * Web 2.0: Social web, AJAX, user-generated content.     * Web 3.0: Artificial Intelligence, personalization, and the "Semantic Web".     * Web 4.0: The Web as a global database and ubiquitous operating system.