struct UUID

Overview

Represents a UUID (Universally Unique IDentifier).

NOTE To use UUID, you must explicitly import it with require "uuid"

Included Modules

Defined in:

uuid.cr
uuid/json.cr

Constructors

Class Method Summary

Instance Method Summary

Instance methods inherited from module Comparable(UUID)

<(other : T) : Bool <, <=(other : T) <=, <=>(other : T) <=>, ==(other : T) ==, >(other : T) : Bool >, >=(other : T) >=, clamp(min, max)
clamp(range : Range) clamp

Instance methods inherited from struct Struct

==(other) : Bool ==, hash(hasher) hash, inspect(io : IO) : Nil inspect, pretty_print(pp) : Nil pretty_print, to_s(io : IO) : Nil to_s

Instance methods inherited from struct Value

==(other : JSON::Any)
==(other : YAML::Any)
==(other) ==, dup dup

Instance methods inherited from class Object

! : Bool !, !=(other) !=, !~(other) !~, ==(other) ==, ===(other : JSON::Any)
===(other : YAML::Any)
===(other) ===, =~(other) =~, as(type : Class) as, as?(type : Class) as?, class class, dup dup, hash(hasher)
hash hash, in?(collection : Object) : Bool
in?(*values : Object) : Bool in?, inspect(io : IO) : Nil
inspect : String inspect, is_a?(type : Class) : Bool is_a?, itself itself, nil? : Bool nil?, not_nil!(message)
not_nil! not_nil!, pretty_inspect(width = 79, newline = "\n", indent = 0) : String pretty_inspect, pretty_print(pp : PrettyPrint) : Nil pretty_print, responds_to?(name : Symbol) : Bool responds_to?, tap(&) tap, to_json(io : IO) : Nil
to_json : String to_json, to_pretty_json(indent : String = " ") : String
to_pretty_json(io : IO, indent : String = " ") : Nil to_pretty_json, to_s(io : IO) : Nil
to_s : String to_s, to_yaml(io : IO) : Nil
to_yaml : String to_yaml, try(&) try, unsafe_as(type : T.class) forall T unsafe_as

Class methods inherited from class Object

from_json(string_or_io, root : String)
from_json(string_or_io) from_json, from_yaml(string_or_io : String | IO) from_yaml

Constructor Detail

def self.empty : self #

Generates an empty UUID.

UUID.empty # => UUID(00000000-0000-4000-0000-000000000000)

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def self.new(bytes : StaticArray(UInt8, 16), variant : UUID::Variant | Nil = nil, version : UUID::Version | Nil = nil) #

Generates UUID from bytes, applying version and variant to the UUID if present.


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def self.new(slice : Slice(UInt8), variant : Variant | Nil = nil, version : Version | Nil = nil) #

Creates UUID from 16-bytes slice. Raises if slice isn't 16 bytes long. See #initialize for variant and version.


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def self.new(uuid : UUID, variant : Variant | Nil = nil, version : Version | Nil = nil) #

Creates another UUID which is a copy of uuid, but allows overriding variant or version.


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def self.new(value : String, variant : Variant | Nil = nil, version : Version | Nil = nil) #

Creates new UUID by decoding value string from hyphenated (ie ba714f86-cac6-42c7-8956-bcf5105e1b81), hexstring (ie 89370a4ab66440c8add39e06f2bb6af6) or URN (ie urn:uuid:3f9eaf9e-cdb0-45cc-8ecb-0e5b2bfb0c20) format, raising an ArgumentError if the string does not match any of these formats.


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def self.new(pull : JSON::PullParser) #

Creates UUID from JSON using JSON::PullParser.

NOTE require "uuid/json" is required to opt-in to this feature.

require "json"
require "uuid"
require "uuid/json"

class Example
  include JSON::Serializable

  property id : UUID
end

example = Example.from_json(%({"id": "ba714f86-cac6-42c7-8956-bcf5105e1b81"}))
example.id # => UUID(ba714f86-cac6-42c7-8956-bcf5105e1b81)

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def self.random(random : Random = Random::Secure, variant : Variant = :rfc4122, version : Version = :v4) : self #

Generates RFC 4122 v4 UUID.

It is strongly recommended to use a cryptographically random source for random, such as Random::Secure.


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Class Method Detail

def self.from_json_object_key?(key : String) #

Deserializes the given JSON key into a UUID.

NOTE require "uuid/json" is required to opt-in to this feature.


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def self.parse?(value : String, variant : Variant | Nil = nil, version : Version | Nil = nil) : UUID | Nil #

Creates new UUID by decoding value string from hyphenated (ie ba714f86-cac6-42c7-8956-bcf5105e1b81), hexstring (ie 89370a4ab66440c8add39e06f2bb6af6) or URN (ie urn:uuid:3f9eaf9e-cdb0-45cc-8ecb-0e5b2bfb0c20) format, returning nil if the string does not match any of these formats.


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Instance Method Detail

def <=>(other : UUID) : Int32 #
Description copied from module Comparable(UUID)

The comparison operator. Returns 0 if the two objects are equal, a negative number if this object is considered less than other, a positive number if this object is considered greater than other, or nil if the two objects are not comparable.

Subclasses define this method to provide class-specific ordering.

The comparison operator is usually used to sort values:

# Sort in a descending way:
[3, 1, 2].sort { |x, y| y <=> x } # => [3, 2, 1]

# Sort in an ascending way:
[3, 1, 2].sort { |x, y| x <=> y } # => [1, 2, 3]

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def ==(other : self) #

def bytes : StaticArray(UInt8, 16) #

Returns the binary representation of the UUID.


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def hash(hasher) #
Description copied from struct Struct

See Object#hash(hasher)


def hexstring : String #

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def inspect(io : IO) : Nil #

Convert to String in literal format.


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def to_json(json : JSON::Builder) : Nil #

Returns UUID as JSON value.

NOTE require "uuid/json" is required to opt-in to this feature.

uuid = UUID.new("87b3042b-9b9a-41b7-8b15-a93d3f17025e")
uuid.to_json # => "\"87b3042b-9b9a-41b7-8b15-a93d3f17025e\""

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def to_s(io : IO) : Nil #
Description copied from struct Struct

Same as #inspect(io).


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def to_unsafe #

Returns unsafe pointer to 16-bytes.


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def urn : String #

Returns a String that is a valid urn of self

require "uuid"

uuid = UUID.empty
uuid.urn # => "urn:uuid:00000000-0000-4000-0000-000000000000"
uuid2 = UUID.new("c49fc136-9362-4414-81a5-9a7e0fcca0f1")
uuid2.urn # => "urn:uuid:c49fc136-9362-4414-81a5-9a7e0fcca0f1"

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def v1! #

Returns true if UUID is a V1, raises Error otherwise.


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def v1? #

Returns true if UUID is a V1, false otherwise.


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def v2! #

Returns true if UUID is a V2, raises Error otherwise.


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def v2? #

Returns true if UUID is a V2, false otherwise.


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def v3! #

Returns true if UUID is a V3, raises Error otherwise.


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def v3? #

Returns true if UUID is a V3, false otherwise.


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def v4! #

Returns true if UUID is a V4, raises Error otherwise.


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def v4? #

Returns true if UUID is a V4, false otherwise.


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def v5! #

Returns true if UUID is a V5, raises Error otherwise.


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def v5? #

Returns true if UUID is a V5, false otherwise.


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def variant : UUID::Variant #

Returns UUID variant based on the RFC4122 format. See also #version

require "uuid"

UUID.new(Slice.new(16, 0_u8), variant: UUID::Variant::NCS).variant       # => UUID::Variant::NCS
UUID.new(Slice.new(16, 0_u8), variant: UUID::Variant::RFC4122).variant   # => UUID::Variant::RFC4122
UUID.new(Slice.new(16, 0_u8), variant: UUID::Variant::Microsoft).variant # => UUID::Variant::Microsoft
UUID.new(Slice.new(16, 0_u8), variant: UUID::Variant::Future).variant    # => UUID::Variant::Future

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def version : UUID::Version #

Returns version based on RFC4122 format. See also #variant.

require "uuid"

UUID.new(Slice.new(16, 0_u8), version: UUID::Version::V1).version # => UUID::Version::V1
UUID.new(Slice.new(16, 0_u8), version: UUID::Version::V2).version # => UUID::Version::V2
UUID.new(Slice.new(16, 0_u8), version: UUID::Version::V3).version # => UUID::Version::V3
UUID.new(Slice.new(16, 0_u8), version: UUID::Version::V4).version # => UUID::Version::V4
UUID.new(Slice.new(16, 0_u8), version: UUID::Version::V5).version # => UUID::Version::V5

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