domain-name 0.1.2 · OCaml Package

type t

The type of a domain name, a sequence of labels separated by dots. Each label may contain any bytes. The length of each label may not exceed 63 charactes. The total length of a domain name is limited to 253 (byte representation is 255), but other protocols (such as SMTP) may apply even smaller limits. A domain name label is case preserving, comparison is done in a case insensitive manner. Every t is a fully qualified domain name, its last label is the root label.

The invariants on the length of domain names are preserved throughout the module - no t will exist which violates these.

The specification of domain names originates from RFC 1035.

Constructing a t (via of_string, of_string_exn, of_strings) does not require a trailing dot.

0.1.2 - homepage

Constructor

val root : t

root is the root domain ("."), the empty label.

String representation

val of_string : ?hostname:bool -> string -> (t, [> `Msg of string ]) result

of_string ~hostname name is either t, the domain name, or an error if the provided name is not a valid domain name. If hostname is provided and true (the default), the contents is additionally checked for being a valid hostname using is_hostname. A trailing dot is not requred.

val of_string_exn : ?hostname:bool -> string -> t

of_string_exn ~hostname name is t, the domain name. If hostname is provided and true (the default), the contents is additionally checked for being a valid hostname using is_hostname. A trailing dot is not required.

raises Invalid_argument
if name is not a valid domain name.

val to_string : ?trailing:bool -> t -> string

to_string ~trailing t is String.concat ~sep:"." (to_strings t), a human-readable representation of t. If trailing is provided and true (defaults to false), the resulting string will contain a trailing dot.

Predicates and basic operations

val canonical : t -> t

canonical t is t', the canonical domain name, as specified in RFC 4034 (and 2535): all characters are lowercase.

val is_hostname : t -> bool

is_hostname t is true if t is a hostname: the contents of the domain name is limited: each label may start with a digit or letter, followed by digits, letters, or hyphens.

val is_service : t -> bool

is_service t is true if t contains a service label - if: The first label is a service name (or port number); an underscore preceding 1-15 characters from the set - a-z A-Z 0-9. The service name may not contain a hyphen (-) following another hyphen; no hyphen at the beginning or end.

The second label is the protocol, one of _tcp, _udp, or _sctp. The remaining labels must form a valid hostname.

This function can be used to validate RR's of the types SRV (RFC 2782) and TLSA (RFC 7671).

val sub : subdomain:t -> domain:t -> bool

sub ~subdomain ~domain is true if subdomain contains any labels prepended to domain: foo.bar.com is a subdomain of bar.com and of com, sub ~subdomain:x ~domain:root is true for all x.

val prepend : ?hostname:bool -> t -> string -> (t, [> `Msg of string ]) result

Label addition and removal

prepend ~hostname name pre is either t, the new domain name, or an error. If hostname is provided and true (the default), the resulting domain name is checked for being a valid host name using is_hostname.

val prepend_exn : ?hostname:bool -> t -> string -> t

prepend_exn ~hostname name pre is t, the new domain name.

raises Invalid_argument
if pre is not a valid domain name. If hostname is provided and true (the default), the contents is additionally checked for being a valid host name using is_hostname.

val drop_labels : 
  ?back:bool ->
  ?amount:int ->
  t ->
  (t, [> `Msg of string ]) result

drop_labels ~back ~amount t is either t, a domain name with amount (defaults to 1) labels dropped from the beginning (unless back is provided and true, defaults to false). drop_labels applied to foo.com is com.

val drop_labels_exn : ?back:bool -> ?amount:int -> t -> t

drop_labels_exn ~back ~amount t is either t, a domain name with amount (defaults to 1) labels dropped from the beginning (unless back is provided and true, defaults to false). drop_labels applied to foo.com is com.

raises Invalid_argument
if there are not sufficient labels.

Comparison

val equal : ?case_sensitive:bool -> t -> t -> bool

equal ~case t t' is true if all labels of t and t' are equal. If case_sensitive is provided and true, the cases of the labels are respected (default: false).

val compare : t -> t -> int

compare t t' compares the domain names t and t' using a case insensitive string comparison.

val compare_sub : string -> string -> int

compare_sub t t' compares the labels t and t' using a case insensitive string comparison.

Collections

module Map : sig ... end

The module of a domain name map

module Set : Set.S with type elt = t

The module of a domain name set

String list representation

val of_strings : 
  ?hostname:bool ->
  string list ->
  (t, [> `Msg of string ]) result

of_strings ~hostname labels is either t, a domain name, or an error if the provided labels violate domain name constraints. If hostname is provided and true (the default), the labels are additionally checked for being a valid hostname using is_hostname. A trailing empty label is not required.

val of_strings_exn : ?hostname:bool -> string list -> t

of_strings_exn ~hostname labels is t, a domain name. A trailing empty label is not required.

raises Invalid_argument
if labels are not a valid domain name. If hostname is provided and true (the default), the labels are additionally checked for being a valid hostname using is_hostname.

val to_strings : ?trailing:bool -> t -> string list

to_strings ~trailing t is the list of labels of t. If trailing is provided and true (defaults to false), the resulting list will contain a trailing empty label.

Pretty printer

val pp : t Fmt.t

pp ppf t pretty prints the domain name t on ppf.

package domain-name