Uri

This repository contains the implementation of the URI.

Uniform Resource Identifier

A Uniform Resource Identifier (URI) is a compact sequence of characters that identifies an abstract or physical resource. URI specification is described in RFC 3986.

Syntax

RFC 3986 (Section 3)

URI = scheme ":" hier-part [ "?" query ] [ "#" fragment ]

hier-part = "//" authority path-abempty / path-absolute / path-rootless / path-empty

     foo://example.com:8042/over/there?name=ferret#nose
     \_/   \______________/\_________/ \_________/ \__/
      |           |            |            |        |
   scheme     authority       path        query   fragment
      |   _____________________|__
     / \ /                        \
     urn:example:animal:ferret:nose

The scheme and path components are required, though the path may be empty (no characters). When authority is present, the path must either be empty or begin with a slash ("/") character. When authority is not present, the path cannot begin with two slash characters ("//").

For more detailed information about URI components see:

• Scheme: RFC 3986 (Section 3.1)
• Authority: RFC 3986 (Section 3.2)
  • User Information: RFC 3986 (Section 3.2.1)
  • Host: RFC 3986 (Section 3.2.2)
  • Port: RFC 3986 (Section 3.2.3)
• Path: RFC 3986 (Section 3.3)
• Query: RFC 3986 (Section 3.4)
• Fragment: RFC 3986 (Section 3.5)

Percent-Encoding

RFC 3986 (Section 2.1)

A percent-encoding mechanism is used to represent a data octet in a component when that octet's corresponding character is outside the allowed set or is being used as a delimiter of, or within, the component. A percent-encoded octet is encoded as a character triplet, consisting of the percent character "%" followed by the two hexadecimal digits representing that octet's numeric value. For example, "%20" is the percent-encoding for the binary octet "00100000" (ABNF: %x20), which in US-ASCII corresponds to the space character (SP).

Reserved sets of characters

The following character must be percent-encoded if they are a part of data:

• ":", "/", "?", "#", "[", "]", "@"
• "!", "$", "&", "'", "(", ")", "*", "+", ",", ";", "="

Unreserved set of characters

The following characters do not need to be percent-encoded:

• ALPHA, DIGIT, "-", ".", "_", "~"

*Note: URIs that differ in the replacement of an unreserved character with its corresponding percent-encoded US-ASCII octet are equivalent. *

Examples of URIs

The following example of URIs illustrate several URI schemes and variations in their common syntax components:

• ftp://ftp.is.co.za/rfc/rfc1808.txt
• http://www.ietf.org/rfc/rfc2396.txt
• ldap://[2001:db8::7]/c=GB?objectClass?one
• mailto:[email protected]
• news:comp.infosystems.www.servers.unix
• tel:+1-816-555-1212
• telnet://192.0.2.16:80/
• urn:oasis:names:specification:docbook:dtd:xml:4.1.2

URI Reference

RFC 3986 (Section 4.1)

URI-reference = URI / relative-ref

A URI-reference is either a URI or a relative reference. If the URI-reference's prefix does not match the syntax of a scheme followed by its colon separator, then the URI-reference is a relative reference.

Relative Reference

RFC 3986 (Section 4.2)

relative-ref = relative-part [ "?" query ] [ "#" fragment ]

A relative reference that begins with two slash characters is termed a network-path reference; such references are rarely used. A relative reference that begins with a single slash character is termed an absolute-path reference. A relative reference that does not begin with a slash character is termed a relative-path reference.

Notes

• The scheme and path components are required, though the path may be empty (no characters).
• The syntax rule for host is ambiguous because it does not completely distinguish between an IPv4address and a reg-name. In order to disambiguate the syntax, we apply the "first-match-wins" algorithm: If host matches the rule for IPv4address, then it should be considered an IPv4 address literal and not a reg-name.

Known limitations

• Parsing of UTF-8 encoded Host component has not been yet implemented.
• Parsing of an IPv6 address in which two least significant peaces are represented as an IPv4 address has not been yet implemented.

License

This program is distributed under The MIT License. See LICENSE.txt file.