The Anatomy of a URL

The anatomy of a URL

A URL, or Uniform Resource Locator, is used to locate files that exist on servers.

Think of URLs as instructions for a client, telling them exactly where to get a certain web page.

URLs consist of the following parts:

• The protocol in use
• The hostname of the server
• The location of the file
• The arguments to the file

Protocol

The protocol part of the URL tells the client what conventions to follow when exchanging messages with the server that has the website. In the case of the example above, the convention is HTTP.

Host name

The hostname is how the client knows which server to contact. In the case of the example above, the hostname is www.educative.io.

Hostnames are pseudonyms for the server, because their actual addresses are numerical and are called IP addresses. Clients get the hostname translated to an IP address first using the domain name system, or DNS. To learn more about DNS, consider taking our course, Grokking Computer Networking for Software Engineers.

Location

This is a simple path to the resource on the server. In the case of the example above, the requested resource is the file course.php in the allcourses directory under the root directory of the webserver. However, it can also be something like a web framework, such as Spring or Django, which will have a path like ‘/allcourses/teach’.

Arguments

These are arguments that can be given to a page which allows the page to render a specific version of the website. In the case above, the argument is some identification of the user.