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diff --git a/Doc/library/uuid.rst b/Doc/library/uuid.rst new file mode 100644 index 0000000..dd52638 --- /dev/null +++ b/Doc/library/uuid.rst @@ -0,0 +1,258 @@ + +:mod:`uuid` --- UUID objects according to RFC 4122 +================================================== + +.. module:: uuid + :synopsis: UUID objects (universally unique identifiers) according to RFC 4122 +.. moduleauthor:: Ka-Ping Yee <ping@zesty.ca> +.. sectionauthor:: George Yoshida <quiver@users.sourceforge.net> + + +.. versionadded:: 2.5 + +This module provides immutable :class:`UUID` objects (the :class:`UUID` class) +and the functions :func:`uuid1`, :func:`uuid3`, :func:`uuid4`, :func:`uuid5` for +generating version 1, 3, 4, and 5 UUIDs as specified in :rfc:`4122`. + +If all you want is a unique ID, you should probably call :func:`uuid1` or +:func:`uuid4`. Note that :func:`uuid1` may compromise privacy since it creates +a UUID containing the computer's network address. :func:`uuid4` creates a +random UUID. + + +.. class:: UUID([hex[, bytes[, bytes_le[, fields[, int[, version]]]]]]) + + Create a UUID from either a string of 32 hexadecimal digits, a string of 16 + bytes as the *bytes* argument, a string of 16 bytes in little-endian order as + the *bytes_le* argument, a tuple of six integers (32-bit *time_low*, 16-bit + *time_mid*, 16-bit *time_hi_version*, 8-bit *clock_seq_hi_variant*, 8-bit + *clock_seq_low*, 48-bit *node*) as the *fields* argument, or a single 128-bit + integer as the *int* argument. When a string of hex digits is given, curly + braces, hyphens, and a URN prefix are all optional. For example, these + expressions all yield the same UUID:: + + UUID('{12345678-1234-5678-1234-567812345678}') + UUID('12345678123456781234567812345678') + UUID('urn:uuid:12345678-1234-5678-1234-567812345678') + UUID(bytes='\x12\x34\x56\x78'*4) + UUID(bytes_le='\x78\x56\x34\x12\x34\x12\x78\x56' + + '\x12\x34\x56\x78\x12\x34\x56\x78') + UUID(fields=(0x12345678, 0x1234, 0x5678, 0x12, 0x34, 0x567812345678)) + UUID(int=0x12345678123456781234567812345678) + + Exactly one of *hex*, *bytes*, *bytes_le*, *fields*, or *int* must be given. + The *version* argument is optional; if given, the resulting UUID will have its + variant and version number set according to RFC 4122, overriding bits in the + given *hex*, *bytes*, *bytes_le*, *fields*, or *int*. + +:class:`UUID` instances have these read-only attributes: + + +.. attribute:: UUID.bytes + + The UUID as a 16-byte string (containing the six integer fields in big-endian + byte order). + + +.. attribute:: UUID.bytes_le + + The UUID as a 16-byte string (with *time_low*, *time_mid*, and *time_hi_version* + in little-endian byte order). + + +.. attribute:: UUID.fields + + A tuple of the six integer fields of the UUID, which are also available as six + individual attributes and two derived attributes: + + +------------------------------+-------------------------------+ + | Field | Meaning | + +==============================+===============================+ + | :attr:`time_low` | the first 32 bits of the UUID | + +------------------------------+-------------------------------+ + | :attr:`time_mid` | the next 16 bits of the UUID | + +------------------------------+-------------------------------+ + | :attr:`time_hi_version` | the next 16 bits of the UUID | + +------------------------------+-------------------------------+ + | :attr:`clock_seq_hi_variant` | the next 8 bits of the UUID | + +------------------------------+-------------------------------+ + | :attr:`clock_seq_low` | the next 8 bits of the UUID | + +------------------------------+-------------------------------+ + | :attr:`node` | the last 48 bits of the UUID | + +------------------------------+-------------------------------+ + | :attr:`time` | the 60-bit timestamp | + +------------------------------+-------------------------------+ + | :attr:`clock_seq` | the 14-bit sequence number | + +------------------------------+-------------------------------+ + + +.. attribute:: UUID.hex + + The UUID as a 32-character hexadecimal string. + + +.. attribute:: UUID.int + + The UUID as a 128-bit integer. + + +.. attribute:: UUID.urn + + The UUID as a URN as specified in RFC 4122. + + +.. attribute:: UUID.variant + + The UUID variant, which determines the internal layout of the UUID. This will be + one of the integer constants :const:`RESERVED_NCS`, :const:`RFC_4122`, + :const:`RESERVED_MICROSOFT`, or :const:`RESERVED_FUTURE`. + + +.. attribute:: UUID.version + + The UUID version number (1 through 5, meaningful only when the variant is + :const:`RFC_4122`). + +The :mod:`uuid` module defines the following functions: + + +.. function:: getnode() + + Get the hardware address as a 48-bit positive integer. The first time this + runs, it may launch a separate program, which could be quite slow. If all + attempts to obtain the hardware address fail, we choose a random 48-bit number + with its eighth bit set to 1 as recommended in RFC 4122. "Hardware address" + means the MAC address of a network interface, and on a machine with multiple + network interfaces the MAC address of any one of them may be returned. + +.. index:: single: getnode + + +.. function:: uuid1([node[, clock_seq]]) + + Generate a UUID from a host ID, sequence number, and the current time. If *node* + is not given, :func:`getnode` is used to obtain the hardware address. If + *clock_seq* is given, it is used as the sequence number; otherwise a random + 14-bit sequence number is chosen. + +.. index:: single: uuid1 + + +.. function:: uuid3(namespace, name) + + Generate a UUID based on the MD5 hash of a namespace identifier (which is a + UUID) and a name (which is a string). + +.. index:: single: uuid3 + + +.. function:: uuid4() + + Generate a random UUID. + +.. index:: single: uuid4 + + +.. function:: uuid5(namespace, name) + + Generate a UUID based on the SHA-1 hash of a namespace identifier (which is a + UUID) and a name (which is a string). + +.. index:: single: uuid5 + +The :mod:`uuid` module defines the following namespace identifiers for use with +:func:`uuid3` or :func:`uuid5`. + + +.. data:: NAMESPACE_DNS + + When this namespace is specified, the *name* string is a fully-qualified domain + name. + + +.. data:: NAMESPACE_URL + + When this namespace is specified, the *name* string is a URL. + + +.. data:: NAMESPACE_OID + + When this namespace is specified, the *name* string is an ISO OID. + + +.. data:: NAMESPACE_X500 + + When this namespace is specified, the *name* string is an X.500 DN in DER or a + text output format. + +The :mod:`uuid` module defines the following constants for the possible values +of the :attr:`variant` attribute: + + +.. data:: RESERVED_NCS + + Reserved for NCS compatibility. + + +.. data:: RFC_4122 + + Specifies the UUID layout given in :rfc:`4122`. + + +.. data:: RESERVED_MICROSOFT + + Reserved for Microsoft compatibility. + + +.. data:: RESERVED_FUTURE + + Reserved for future definition. + + +.. seealso:: + + :rfc:`4122` - A Universally Unique IDentifier (UUID) URN Namespace + This specification defines a Uniform Resource Name namespace for UUIDs, the + internal format of UUIDs, and methods of generating UUIDs. + + +.. _uuid-example: + +Example +------- + +Here are some examples of typical usage of the :mod:`uuid` module:: + + >>> import uuid + + # make a UUID based on the host ID and current time + >>> uuid.uuid1() + UUID('a8098c1a-f86e-11da-bd1a-00112444be1e') + + # make a UUID using an MD5 hash of a namespace UUID and a name + >>> uuid.uuid3(uuid.NAMESPACE_DNS, 'python.org') + UUID('6fa459ea-ee8a-3ca4-894e-db77e160355e') + + # make a random UUID + >>> uuid.uuid4() + UUID('16fd2706-8baf-433b-82eb-8c7fada847da') + + # make a UUID using a SHA-1 hash of a namespace UUID and a name + >>> uuid.uuid5(uuid.NAMESPACE_DNS, 'python.org') + UUID('886313e1-3b8a-5372-9b90-0c9aee199e5d') + + # make a UUID from a string of hex digits (braces and hyphens ignored) + >>> x = uuid.UUID('{00010203-0405-0607-0809-0a0b0c0d0e0f}') + + # convert a UUID to a string of hex digits in standard form + >>> str(x) + '00010203-0405-0607-0809-0a0b0c0d0e0f' + + # get the raw 16 bytes of the UUID + >>> x.bytes + '\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f' + + # make a UUID from a 16-byte string + >>> uuid.UUID(bytes=x.bytes) + UUID('00010203-0405-0607-0809-0a0b0c0d0e0f') + |