HTTP, Servers, and Clients

Introduction

The Internet was created and used initially by researchers, and was generally inaccessible to the public. However, that changed when the World Wide Web caught the public’s eye, and brought the Internet to the mainstream. HTTP or HyperText Transfer Protocol, is at the core of the web. HTTP is a protocol that allows us to access web pages.

Web pages

Before we can understand how HTTP works, we need to understand that the World Wide Web is a web of documents known as web pages. Each web page consists of objects, which could be text, graphics, links to other web pages, or scripts. Each object has a ‘URL,’ or Uniform Resource Locator, which we will talk more about in the next lesson. The base object of a web page is often an HTML file that has references to other objects.

📝 HTML, or HyperText Markup Language, is the standard markup language to build webpages.

Servers and clients

Servers and clients are processesprocesses on devices that communicate with each other through messages. These messages are based on the rules defined by HTTP, which we will explain in an upcoming lesson.

Servers

The server controls access to a centralized resource or service, such as a website. In other words, a server has a website, and it can show that website to other processes, called clients, when asked.

People try to keep servers online at all times, although 100% availability is impossible to achieve. Clients must generally be able to find servers online when needed; otherwise, websites won’t work. So, all possible measures are taken to keep servers online. If we fail to do so, the clients won’t be able to access web resources.

Clients

Client processes use the Internet to consume content and use services. Client processes almost always initiate connections to servers, while server processes wait for requests from clients. So, if you go to google.com, your browser is the client.