URL

History - Uniform Resource Locators (URLs) were defined in RFC1738 in 1994 by Tim Berners-Lee and the URI working group of the Internet Engineering Task Force (IETF). - Early collaborators proposed the use of Universal Document Identifiers (UDIs) before settling on URLs. - The term 'universal' was originally preferred over 'uniform' in the expansion of URL, but it was later changed. - Berners-Lee expressed regret at using dots to separate parts of the domain name within URIs and wished he had used slashes throughout. Syntax - Every HTTP URL conforms to the syntax of a generic URI. - The URI generic syntax consists of five components: scheme, authority, path, query, and fragment. - URI schemes should be registered with the Internet Assigned Numbers Authority (IANA). - The authority component can include userinfo, host, and port subcomponents. - The path component consists of path segments separated by a slash and can resemble a file system path. Usage - URLs are commonly used to reference web pages (HTTP/HTTPS). - URLs are also used for file transfer (FTP), email (mailto), database access (JDBC), and other applications. - Most web browsers display the URL of a web page in an address bar. - A typical URL includes a protocol, hostname, and file name. - In http and https URIs, the last part of the path is often named pathinfo and is used to select dynamic content. Internationalized URL - An Internationalized Resource Identifier (IRI) is a form of URL that includes Unicode characters. - The domain name in an IRI is known as an Internationalized Domain Name (IDN). - Web and Internet software automatically convert IDNs into punycode usable by the Domain Name System. - The URL path name can be specified in the user's local writing system and is converted to UTF-8. - Characters not part of the basic URL character set are escaped using percent-encoding. Related Standards - URL is a specific type of Uniform Resource Identifier (URI). - Other related standards include URI and URN. - The World Wide Web relies on the use of URLs to locate resources. - The URL specification is licensed under CC BY 4.0. - Organizations such as whatwg.org are involved in maintaining and developing URL standards.