links_domainmap

Module domain

Source
Expand description

Types for domain names, either as a reference identifier or a presented identifier, with support for internationalized domain names

Rules for domain names as implemented here (based on a mix of RFC 952, RFC 1034, RFC 1123, RFC 2181, the WHATWG URL specification, browser implementations, and browser bugs) are:

  • A domain name has a maximum total length (including ’.’s) of 253 characters/octets/bytes (RFC 1034 section 3.1, Unicode TR46 section 4)
  • Domain name labels (the things seperated by ‘.’) have a maximum length of 63 characters/octets/bytes each, not including the separators (RFC 1034 section 3.5, RFC 1123 section 2.1, RFC 2181 section 11)
  • A domain name label must consist of only ASCII letters ('a'..='z' | 'A'..='Z'), digits ('0'..='9'), and hyphens ('-'). A label can not start or end with a hyphen. (RFC 952 section B, RFC 1034 section 3.5, RFC 1123 section 2.1)
  • Additionally, a label can also contain underscores ('_') in the same places as letters for compatibility reasons. (Additional discussion around underscores in a Firefox bug, implementations in Chromium and Firefox)
  • A wildcard ("*") can only comprise the entire left-most label of a domain name and matches exactly one label. ([RFC 2818] section 3.1, RFC 6125 section 6.4.3; i.e. "*.example.com" is valid and matches "foo.example.com" and "bar.example.com" but does not match "foo.bar.example.com" or "example.com", and all of the following are invalid: "*.*.example.com", "foo.*.example.com", "fo*.example.com", "*oo.example.com", "f*o.example.com")
  • No special treatment is given to wildcards on top-level domains (e.g. "*.com"), or on other public suffixes (e.g. “*.co.uk” or "*.pvt.k12.ma.us"), which allows some potentially invalid wildcard domains; full wildcard domains ("*") are not allowed
  • Percent-encoded domain names (e.g. "e%78ample.com") are not supported, and '%' is treated as an invalid character

Structs§

Domain
A domain name split into individual labels (not including the root label).
Label
A domain name label, stored in lowercase in its ASCII-encoded form

Enums§

ParseError
An error encountered while parsing a domain name