Web Introduction and Architecture

Objectives

• Understand the World Wide Web (WWW) and its operation.
• Learn about the architecture and technologies that support the WWW.
• Familiarize with web applications and their development processes.

Evolution of the Web

• The first website was created at CERN, marking the birth of the web.
• The web has significantly evolved since its inception, with substantial developments over time.

World Wide Web (WWW)

• The WWW is a distributed, collaborative, hypermedia information system built on the Internet's infrastructure.
• Resources on the web are identified by Uniform Resource Identifiers (URIs).

Internet

• A network of networks governed by TCP/IP standards, enabling global communication and data interchange.
• Offers various resources, including web documents, email, and file sharing.

Tim Berners-Lee

• Inventor of the WWW, developed crucial technologies: HTTP, URL, and HTML.
• Established the World Wide Web Consortium (W3C) to guide web standards and protocols.

WWW Core Components

• Web Resources:
  • Web Pages: HTML documents featuring information and hyperlinks.
  • May include scripts, stylesheets, and multimedia; can be static or dynamic.
• Websites: Collections of web resources under a unified domain.
• Web Applications: Websites designed with application logic to perform specific tasks (e.g., online banking, media streaming).

Web Servers

• Host web resources and can operate multiple websites or applications.
• Examples include Apache's HTTP Server and Microsoft's IIS for web servers, while Oracle's WebLogic and IBM’s WebSphere serve as application servers.

Web Clients

• Software used to access web resources, primarily web browsers.
• Includes any end-user tools or applications using web protocols, e.g., mobile weather apps.

Uniform Resource Locator (URL)

• A unique reference identifier for web resources, crucial for navigation and access.

Hypertext Transfer Protocol (HTTP)

• Communication protocol facilitating interaction between clients and servers.
• Clients issue HTTP request messages, while servers respond with HTTP response messages.
• The payload includes resources sent by the server (e.g., HTML pages) and data sent by clients (e.g., uploads).

The WWW Now

• Modern web applications encompass a vast range of services, including:
  • Search engines
  • Banking and e-commerce platforms
  • E-governance solutions
  • Social networks
  • Entertainment and media streaming services
  • Learning management systems
  • Scientific research tools
  • Website builders