Structure of the Internet: URIs
Resources such as documents, files and folders sitting on the internet need a method to identify them and access them. URIs provide a way to linking to these resources. There are two types of URI, but you only need to know URL for the exam:
- Uniform Resource Name (URN) - the name of a resource, but not its exact location.
- Uniform Resource Locator (URL) - the exact location of a resource.
The project gutenberg page for the R.U.R. book
Uniform Resource Locator (URL)
A URL is a URI that, "in addition to identifying a resource, provides a means of locating the resource by describing its primary access mechanism (e.g., its network location)". URLs allow us to specify the domain name and exact location of a resource on the internet. For example, the following links to a picture on wikicommons:
We can break this down into its constituent parts:
We can therefore summarise a URL as follows:
- Tim Berners-Lee, Roy T. Fielding, Larry Masinter. (January 2005). “Uniform Resource Identifier (URI): Generic Syntax”. Internet Society. RFC 3986; STD 66.