URI

External

• Uniform Resource Identifier (URI): Generic Syntax https://tools.ietf.org/html/rfc3986
• URI Template https://tools.ietf.org/html/rfc6570
• Format for Literal IPv6 Addresses in URLs http://www.ietf.org/rfc/rfc2732.txt
• https://danielmiessler.com/study/url-uri/

Internal

• REST and Hypermedia
• URL
• URN
• Best Practices for Naming REST API URIs

Overview

A Uniform Resource Identifier (URI) is a compact sequence of characters that identifies an abstract or physical resource. An URI can be a URL or an URN. Every URL is a URI, abstractly speaking, but not every URI is a URL.

REST APIs use URIs to address resources. Best Practices for Naming REST API URIs contains some rules to use when creating URIs for resources.

Tim Berners-Lee: "The only thing you can use an identifier for is to refer to an object. When you are not dereferencing, you should not look at the contents of the URI string to gain information". This seems to advocate for URI opacity. However, REST API designers should create URIs that convey a REST API's resource model to its clients.

Format

RFC 3986 defines the generic URI syntax:

scheme "://" authority "/" path [ "?" query ] [ "#" fragment ]

Authority

Also see:

REST API Authority Rules

Query

Also see:

REST API Query Rules

URI Template

https://datatracker.ietf.org/doc/html/draft-gregorio-uritemplate