This module provides immutable UUID objects (the UUID class)
and the functions uuid1(), uuid3(),
uuid4(), 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
uuid1() or uuid4(). Note that uuid1()
may compromise privacy since it creates a UUID containing the computer's
network address. uuid4() creates a random UUID.
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:
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.
UUID instances have these read-only attributes:
bytes
The UUID as a 16-byte string (containing the six
integer fields in big-endian byte order).
bytes_le
The UUID as a 16-byte string (with time_low, time_mid,
and time_hi_version in little-endian byte order).
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
time_low
the first 32 bits of the UUID
time_mid
the next 16 bits of the UUID
time_hi_version
the next 16 bits of the UUID
clock_seq_hi_variant
the next 8 bits of the UUID
clock_seq_low
the next 8 bits of the UUID
node
the last 48 bits of the UUID
time
the 60-bit timestamp
clock_seq
the 14-bit sequence number
hex
The UUID as a 32-character hexadecimal string.
int
The UUID as a 128-bit integer.
urn
The UUID as a URN as specified in RFC 4122.
variant
The UUID variant, which determines the internal layout of the UUID.
This will be one of the integer constants
RESERVED_NCS,
RFC_4122, RESERVED_MICROSOFT, or
RESERVED_FUTURE.
version
The UUID version number (1 through 5, meaningful only
when the variant is RFC_4122).
The uuid module defines the following functions:
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.
uuid1(
[node[, clock_seq]])
Generate a UUID from a host ID, sequence number, and the current time.
If node is not given, 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.
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).
uuid4(
)
Generate a random UUID.
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).
The uuid module defines the following namespace identifiers
for use with uuid3() or uuid5().
NAMESPACE_DNS
When this namespace is specified,
the name string is a fully-qualified domain name.
NAMESPACE_URL
When this namespace is specified,
the name string is a URL.
NAMESPACE_OID
When this namespace is specified,
the name string is an ISO OID.
NAMESPACE_X500
When this namespace is specified,
the name string is an X.500 DN in DER or a text output format.
The uuid module defines the following constants
for the possible values of the variant attribute: