Understanding the Web Development

Developing for the web means developing with Hypertext Transfer Protocol (HTTP), so we will start by reviewing this important foundational technology.

Understanding Hypertext Transfer Protocol

To communicate with a web server, the client (also known as the user agent) makes calls over the network using HTTP. As such, HTTP is the technical underpinning of the web. So, when we talk about websites and web services, we mean that they use HTTP to communicate between a client (often a web browser) and a server.

A client makes an HTTP request for a resource, such as a page, uniquely identified by a Uniform Resource Locator (URL), and the server sends back an HTTP response, as shown in the figure:

We can use Google Chrome and other browsers to record requests and responses.

Understanding the components of a URL

A Uniform Resource Locator (URL) is made up of several components:

• Scheme: http (clear text) or https (encrypted).

• Domain: For a production website or service, the top-level domain (TLD) might be example.com. We might have subdomains such as www, jobs, or extranet. During development, we typically use localhost for all websites and services.

• Port number: For a production website or service, $80$ for http, ...