Uniform resource identifier (URI) and URL

From Computer Science Wiki


Web Science[1]

Students will be expected to not only define, but also discuss the characteristics of URL and URI. Students will also be expected to describe the purpose of a URL.

Characteristics of a URL[edit]

A Uniform Resource Locator (URL), is a reference to a web resource that specifies its location on a computer network and a mechanism for retrieving it. A URL is a specific type of Uniform Resource Identifier (URI).[2]

  • URL's have different parts. Every URL MUST have:
    • scheme and host
  • URL's have different parts. Every URL MIGHT have:
    • user information
    • port
    • query
    • fragment

Please click here for an example of these different parts. In your normal day-to-day use, you probably only use a scheme and a host.

Example of a URL[edit]

The following figure displays two example URIs and their component parts.

                    hierarchical part
        ┌───────────────────┴─────────────────────┐
                    authority               path
        ┌───────────────┴───────────────┐┌───┴────┐
  abc://username:password@example.com:123/path/data?key=value&key2=value2#fragid1
  └┬┘   └───────┬───────┘ └────┬────┘ └┬┘           └─────────┬─────────┘ └──┬──┘
scheme  user information     host     port                  query         fragment

  urn:example:mammal:monotreme:echidna
  └┬┘ └──────────────┬───────────────┘
scheme              path

Purpose of a URL[edit]

Do you understand this?[edit]

Standards[edit]

These standards are used from the IB Computer Science Subject Guide[3]

  • Identify the characteristics of a uniform resource identifier (URI) URL.
  • Describe the purpose of a URL.

References[edit]

  1. http://www.flaticon.com/
  2. https://en.wikipedia.org/wiki/URL
  3. IB Diploma Programme Computer science guide (first examinations 2014). Cardiff, Wales, United Kingdom: International Baccalaureate Organization. January 2012.