Crate fqdn

source ·
Expand description

A fully qualified domain name representation

Notice that a fully qualified domain name (FQDN) is case-insensitive. So the implementation of traits Hash, PartialEq, Eq, PartialOrd and Ord do the same.

§Crate features

These features control how the parsing of a string should be done. Violation of one of these activated limitations raises an error (see Error).

Some limitations are set by the Internet RFC but, by default, some of them are relaxed to fit with more applicative contexts. The following features are available in order to activate or not these limitations, depending on applicative purposes.

§domain-label-length-limited-to-63

The internet standards specifies that each label of a FQDN is limited to 63 characters. By default, this crate allows up to 256 characters but the 63 limitation could be set through the activation of this feature.

§domain-name-length-limited-to-255

The internet standards specifies that the total length of a FQDN is limited to 255 characters. By default, the only limit is the available memory but the 255 limitation could be set through the activation of this feature.

§domain-name-without-special-chars

The internet standards specifies that a FQDN should only contain digits, letters and hyphens (-). But, many network equipment accept also _ (underscore) without any problem. If this crate is used to design something like a firewall, it could be necessary to deal with this, so do this feature. At the contrary, the activation of this feature refuses these special characters.

§domain-label-should-start-with-letter

The internet standards specifies that FQDN should always start with a letter (nor a digit, nor a hyphen). By default, this crate accept any of these characters event at the first position. The activation of this feature forces the use of a letter at the beginning of FQDN.

§domain-label-should-have-trailing-dot

The internet standards specifies that the human-readable representation of FQDN should always end with a dot. If this feature is activated, then parsing or printing a FQDN strictly apply this rule. By default, the parsing behavior is more lenient (i.e. the trailing dot could miss).

The related RFC define some restrictions that are not activated by default. The feature strict-rfc activates all of them, which are:

  • domain-label-length-limited-to-63
  • domain-name-length-limited-to-255
  • domain-name-without-special-chars
  • domain-label-should-start-with-letter
  • domain-label-should-have-trailing-dot

See above for more details.

Macros§

  • fqdn
    Parses a list of strings and creates an new FQDN by concatenating them.

Structs§

  • FQDN
    A FQDN string.
  • Fqdn
    A borrowed FQDN (as a slice).

Enums§

  • Error
    Error when FQDN parsing goes wrong