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r"""UUID objects (universally unique identifiers) according to RFC 4122. 

 

This module provides immutable UUID objects (class UUID) 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. 

 

Typical usage: 

 

>>> import uuid 

 

# make a UUID based on the host ID and current time 

>>> uuid.uuid1() # doctest: +SKIP 

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() # doctest: +SKIP 

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 

b'\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') 

""" 

 

import os 

 

__author__ = 'Ka-Ping Yee <ping@zesty.ca>' 

 

RESERVED_NCS, RFC_4122, RESERVED_MICROSOFT, RESERVED_FUTURE = [ 

'reserved for NCS compatibility', 'specified in RFC 4122', 

'reserved for Microsoft compatibility', 'reserved for future definition'] 

 

int_ = int # The built-in int type 

bytes_ = bytes # The built-in bytes type 

 

class UUID(object): 

"""Instances of the UUID class represent UUIDs as specified in RFC 4122. 

UUID objects are immutable, hashable, and usable as dictionary keys. 

Converting a UUID to a string with str() yields something in the form 

'12345678-1234-1234-1234-123456789abc'. The UUID constructor accepts 

five possible forms: a similar string of hexadecimal digits, or a tuple 

of six integer fields (with 32-bit, 16-bit, 16-bit, 8-bit, 8-bit, and 

48-bit values respectively) as an argument named 'fields', or a string 

of 16 bytes (with all the integer fields in big-endian order) as an 

argument named 'bytes', or a string of 16 bytes (with the first three 

fields in little-endian order) as an argument named 'bytes_le', or a 

single 128-bit integer as an argument named 'int'. 

 

UUIDs 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: 

 

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 (one of the 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) 

""" 

 

def __init__(self, hex=None, bytes=None, bytes_le=None, fields=None, 

int=None, version=None): 

r"""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 set according to RFC 4122, 

overriding the given 'hex', 'bytes', 'bytes_le', 'fields', or 'int'. 

""" 

 

if [hex, bytes, bytes_le, fields, int].count(None) != 4: 

raise TypeError('one of the hex, bytes, bytes_le, fields, ' 

'or int arguments must be given') 

if hex is not None: 

hex = hex.replace('urn:', '').replace('uuid:', '') 

hex = hex.strip('{}').replace('-', '') 

if len(hex) != 32: 

raise ValueError('badly formed hexadecimal UUID string') 

int = int_(hex, 16) 

if bytes_le is not None: 

if len(bytes_le) != 16: 

raise ValueError('bytes_le is not a 16-char string') 

bytes = (bytes_le[4-1::-1] + bytes_le[6-1:4-1:-1] + 

bytes_le[8-1:6-1:-1] + bytes_le[8:]) 

if bytes is not None: 

if len(bytes) != 16: 

raise ValueError('bytes is not a 16-char string') 

assert isinstance(bytes, bytes_), repr(bytes) 

int = int_.from_bytes(bytes, byteorder='big') 

if fields is not None: 

if len(fields) != 6: 

raise ValueError('fields is not a 6-tuple') 

(time_low, time_mid, time_hi_version, 

clock_seq_hi_variant, clock_seq_low, node) = fields 

if not 0 <= time_low < 1<<32: 

raise ValueError('field 1 out of range (need a 32-bit value)') 

if not 0 <= time_mid < 1<<16: 

raise ValueError('field 2 out of range (need a 16-bit value)') 

if not 0 <= time_hi_version < 1<<16: 

raise ValueError('field 3 out of range (need a 16-bit value)') 

if not 0 <= clock_seq_hi_variant < 1<<8: 

raise ValueError('field 4 out of range (need an 8-bit value)') 

if not 0 <= clock_seq_low < 1<<8: 

raise ValueError('field 5 out of range (need an 8-bit value)') 

if not 0 <= node < 1<<48: 

raise ValueError('field 6 out of range (need a 48-bit value)') 

clock_seq = (clock_seq_hi_variant << 8) | clock_seq_low 

int = ((time_low << 96) | (time_mid << 80) | 

(time_hi_version << 64) | (clock_seq << 48) | node) 

if int is not None: 

if not 0 <= int < 1<<128: 

raise ValueError('int is out of range (need a 128-bit value)') 

if version is not None: 

if not 1 <= version <= 5: 

raise ValueError('illegal version number') 

# Set the variant to RFC 4122. 

int &= ~(0xc000 << 48) 

int |= 0x8000 << 48 

# Set the version number. 

int &= ~(0xf000 << 64) 

int |= version << 76 

self.__dict__['int'] = int 

 

def __eq__(self, other): 

if isinstance(other, UUID): 

return self.int == other.int 

return NotImplemented 

 

# Q. What's the value of being able to sort UUIDs? 

# A. Use them as keys in a B-Tree or similar mapping. 

 

def __lt__(self, other): 

if isinstance(other, UUID): 

return self.int < other.int 

return NotImplemented 

 

def __gt__(self, other): 

if isinstance(other, UUID): 

return self.int > other.int 

return NotImplemented 

 

def __le__(self, other): 

if isinstance(other, UUID): 

return self.int <= other.int 

return NotImplemented 

 

def __ge__(self, other): 

if isinstance(other, UUID): 

return self.int >= other.int 

return NotImplemented 

 

def __hash__(self): 

return hash(self.int) 

 

def __int__(self): 

return self.int 

 

def __repr__(self): 

return '%s(%r)' % (self.__class__.__name__, str(self)) 

 

def __setattr__(self, name, value): 

raise TypeError('UUID objects are immutable') 

 

def __str__(self): 

hex = '%032x' % self.int 

return '%s-%s-%s-%s-%s' % ( 

hex[:8], hex[8:12], hex[12:16], hex[16:20], hex[20:]) 

 

@property 

def bytes(self): 

return self.int.to_bytes(16, 'big') 

 

@property 

def bytes_le(self): 

bytes = self.bytes 

return (bytes[4-1::-1] + bytes[6-1:4-1:-1] + bytes[8-1:6-1:-1] + 

bytes[8:]) 

 

@property 

def fields(self): 

return (self.time_low, self.time_mid, self.time_hi_version, 

self.clock_seq_hi_variant, self.clock_seq_low, self.node) 

 

@property 

def time_low(self): 

return self.int >> 96 

 

@property 

def time_mid(self): 

return (self.int >> 80) & 0xffff 

 

@property 

def time_hi_version(self): 

return (self.int >> 64) & 0xffff 

 

@property 

def clock_seq_hi_variant(self): 

return (self.int >> 56) & 0xff 

 

@property 

def clock_seq_low(self): 

return (self.int >> 48) & 0xff 

 

@property 

def time(self): 

return (((self.time_hi_version & 0x0fff) << 48) | 

(self.time_mid << 32) | self.time_low) 

 

@property 

def clock_seq(self): 

return (((self.clock_seq_hi_variant & 0x3f) << 8) | 

self.clock_seq_low) 

 

@property 

def node(self): 

return self.int & 0xffffffffffff 

 

@property 

def hex(self): 

return '%032x' % self.int 

 

@property 

def urn(self): 

return 'urn:uuid:' + str(self) 

 

@property 

def variant(self): 

if not self.int & (0x8000 << 48): 

return RESERVED_NCS 

elif not self.int & (0x4000 << 48): 

return RFC_4122 

elif not self.int & (0x2000 << 48): 

return RESERVED_MICROSOFT 

else: 

return RESERVED_FUTURE 

 

@property 

def version(self): 

# The version bits are only meaningful for RFC 4122 UUIDs. 

if self.variant == RFC_4122: 

return int((self.int >> 76) & 0xf) 

 

def _popen(command, *args): 

import os, shutil, subprocess 

executable = shutil.which(command) 

if executable is None: 

path = os.pathsep.join(('/sbin', '/usr/sbin')) 

executable = shutil.which(command, path=path) 

if executable is None: 

return None 

# LC_ALL=C to ensure English output, stderr=DEVNULL to prevent output 

# on stderr (Note: we don't have an example where the words we search 

# for are actually localized, but in theory some system could do so.) 

env = dict(os.environ) 

env['LC_ALL'] = 'C' 

proc = subprocess.Popen((executable,) + args, 

stdout=subprocess.PIPE, 

stderr=subprocess.DEVNULL, 

env=env) 

return proc 

 

def _find_mac(command, args, hw_identifiers, get_index): 

try: 

proc = _popen(command, *args.split()) 

if not proc: 

return 

with proc: 

for line in proc.stdout: 

words = line.lower().rstrip().split() 

for i in range(len(words)): 

if words[i] in hw_identifiers: 

try: 

word = words[get_index(i)] 

mac = int(word.replace(b':', b''), 16) 

if mac: 

return mac 

except (ValueError, IndexError): 

# Virtual interfaces, such as those provided by 

# VPNs, do not have a colon-delimited MAC address 

# as expected, but a 16-byte HWAddr separated by 

# dashes. These should be ignored in favor of a 

# real MAC address 

pass 

except OSError: 

pass 

 

def _ifconfig_getnode(): 

"""Get the hardware address on Unix by running ifconfig.""" 

# This works on Linux ('' or '-a'), Tru64 ('-av'), but not all Unixes. 

keywords = (b'hwaddr', b'ether', b'address:', b'lladdr') 

for args in ('', '-a', '-av'): 

mac = _find_mac('ifconfig', args, keywords, lambda i: i+1) 

if mac: 

return mac 

 

def _ip_getnode(): 

"""Get the hardware address on Unix by running ip.""" 

# This works on Linux with iproute2. 

mac = _find_mac('ip', 'link', [b'link/ether'], lambda i: i+1) 

if mac: 

return mac 

 

def _arp_getnode(): 

"""Get the hardware address on Unix by running arp.""" 

import os, socket 

try: 

ip_addr = socket.gethostbyname(socket.gethostname()) 

except OSError: 

return None 

 

# Try getting the MAC addr from arp based on our IP address (Solaris). 

mac = _find_mac('arp', '-an', [os.fsencode(ip_addr)], lambda i: -1) 

if mac: 

return mac 

 

# This works on OpenBSD 

mac = _find_mac('arp', '-an', [os.fsencode(ip_addr)], lambda i: i+1) 

if mac: 

return mac 

 

# This works on Linux, FreeBSD and NetBSD 

mac = _find_mac('arp', '-an', [os.fsencode('(%s)' % ip_addr)], 

lambda i: i+2) 

if mac: 

return mac 

 

def _lanscan_getnode(): 

"""Get the hardware address on Unix by running lanscan.""" 

# This might work on HP-UX. 

return _find_mac('lanscan', '-ai', [b'lan0'], lambda i: 0) 

 

def _netstat_getnode(): 

"""Get the hardware address on Unix by running netstat.""" 

# This might work on AIX, Tru64 UNIX and presumably on IRIX. 

try: 

proc = _popen('netstat', '-ia') 

if not proc: 

return 

with proc: 

words = proc.stdout.readline().rstrip().split() 

try: 

i = words.index(b'Address') 

except ValueError: 

return 

for line in proc.stdout: 

try: 

words = line.rstrip().split() 

word = words[i] 

if len(word) == 17 and word.count(b':') == 5: 

mac = int(word.replace(b':', b''), 16) 

if mac: 

return mac 

except (ValueError, IndexError): 

pass 

except OSError: 

pass 

 

def _ipconfig_getnode(): 

"""Get the hardware address on Windows by running ipconfig.exe.""" 

import os, re, subprocess 

dirs = ['', r'c:\windows\system32', r'c:\winnt\system32'] 

try: 

import ctypes 

buffer = ctypes.create_string_buffer(300) 

ctypes.windll.kernel32.GetSystemDirectoryA(buffer, 300) 

dirs.insert(0, buffer.value.decode('mbcs')) 

except: 

pass 

for dir in dirs: 

try: 

proc = subprocess.Popen([os.path.join(dir, 'ipconfig'), '/all'], 

stdout=subprocess.PIPE, 

encoding="oem") 

except OSError: 

continue 

with proc: 

for line in proc.stdout: 

value = line.split(':')[-1].strip().lower() 

if re.match('([0-9a-f][0-9a-f]-){5}[0-9a-f][0-9a-f]', value): 

return int(value.replace('-', ''), 16) 

 

def _netbios_getnode(): 

"""Get the hardware address on Windows using NetBIOS calls. 

See http://support.microsoft.com/kb/118623 for details.""" 

import win32wnet, netbios 

ncb = netbios.NCB() 

ncb.Command = netbios.NCBENUM 

ncb.Buffer = adapters = netbios.LANA_ENUM() 

adapters._pack() 

if win32wnet.Netbios(ncb) != 0: 

return 

adapters._unpack() 

for i in range(adapters.length): 

ncb.Reset() 

ncb.Command = netbios.NCBRESET 

ncb.Lana_num = ord(adapters.lana[i]) 

if win32wnet.Netbios(ncb) != 0: 

continue 

ncb.Reset() 

ncb.Command = netbios.NCBASTAT 

ncb.Lana_num = ord(adapters.lana[i]) 

ncb.Callname = '*'.ljust(16) 

ncb.Buffer = status = netbios.ADAPTER_STATUS() 

if win32wnet.Netbios(ncb) != 0: 

continue 

status._unpack() 

bytes = status.adapter_address[:6] 

if len(bytes) != 6: 

continue 

return int.from_bytes(bytes, 'big') 

 

# Thanks to Thomas Heller for ctypes and for his help with its use here. 

 

# If ctypes is available, use it to find system routines for UUID generation. 

# XXX This makes the module non-thread-safe! 

_uuid_generate_time = _UuidCreate = None 

try: 

import ctypes, ctypes.util 

import sys 

 

# The uuid_generate_* routines are provided by libuuid on at least 

# Linux and FreeBSD, and provided by libc on Mac OS X. 

_libnames = ['uuid'] 

if not sys.platform.startswith('win'): 

_libnames.append('c') 

for libname in _libnames: 

try: 

lib = ctypes.CDLL(ctypes.util.find_library(libname)) 

except Exception: 

continue 

if hasattr(lib, 'uuid_generate_time'): 

_uuid_generate_time = lib.uuid_generate_time 

break 

del _libnames 

 

# The uuid_generate_* functions are broken on MacOS X 10.5, as noted 

# in issue #8621 the function generates the same sequence of values 

# in the parent process and all children created using fork (unless 

# those children use exec as well). 

# 

# Assume that the uuid_generate functions are broken from 10.5 onward, 

# the test can be adjusted when a later version is fixed. 

if sys.platform == 'darwin': 

if int(os.uname().release.split('.')[0]) >= 9: 

_uuid_generate_time = None 

 

# On Windows prior to 2000, UuidCreate gives a UUID containing the 

# hardware address. On Windows 2000 and later, UuidCreate makes a 

# random UUID and UuidCreateSequential gives a UUID containing the 

# hardware address. These routines are provided by the RPC runtime. 

# NOTE: at least on Tim's WinXP Pro SP2 desktop box, while the last 

# 6 bytes returned by UuidCreateSequential are fixed, they don't appear 

# to bear any relationship to the MAC address of any network device 

# on the box. 

try: 

lib = ctypes.windll.rpcrt4 

except: 

lib = None 

_UuidCreate = getattr(lib, 'UuidCreateSequential', 

getattr(lib, 'UuidCreate', None)) 

except: 

pass 

 

def _unixdll_getnode(): 

"""Get the hardware address on Unix using ctypes.""" 

_buffer = ctypes.create_string_buffer(16) 

_uuid_generate_time(_buffer) 

return UUID(bytes=bytes_(_buffer.raw)).node 

 

def _windll_getnode(): 

"""Get the hardware address on Windows using ctypes.""" 

_buffer = ctypes.create_string_buffer(16) 

if _UuidCreate(_buffer) == 0: 

return UUID(bytes=bytes_(_buffer.raw)).node 

 

def _random_getnode(): 

"""Get a random node ID, with eighth bit set as suggested by RFC 4122.""" 

import random 

return random.getrandbits(48) | 0x010000000000 

 

_node = None 

 

_NODE_GETTERS_WIN32 = [_windll_getnode, _netbios_getnode, _ipconfig_getnode] 

 

_NODE_GETTERS_UNIX = [_unixdll_getnode, _ifconfig_getnode, _ip_getnode, 

_arp_getnode, _lanscan_getnode, _netstat_getnode] 

 

def 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. 

""" 

 

global _node 

if _node is not None: 

return _node 

 

import sys 

if sys.platform == 'win32': 

getters = _NODE_GETTERS_WIN32 

else: 

getters = _NODE_GETTERS_UNIX 

 

for getter in getters + [_random_getnode]: 

try: 

_node = getter() 

except: 

continue 

if (_node is not None) and (0 <= _node < (1 << 48)): 

return _node 

assert False, '_random_getnode() returned invalid value: {}'.format(_node) 

 

_last_timestamp = None 

 

def uuid1(node=None, clock_seq=None): 

"""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.""" 

 

# When the system provides a version-1 UUID generator, use it (but don't 

# use UuidCreate here because its UUIDs don't conform to RFC 4122). 

if _uuid_generate_time and node is clock_seq is None: 

_buffer = ctypes.create_string_buffer(16) 

_uuid_generate_time(_buffer) 

return UUID(bytes=bytes_(_buffer.raw)) 

 

global _last_timestamp 

import time 

nanoseconds = int(time.time() * 1e9) 

# 0x01b21dd213814000 is the number of 100-ns intervals between the 

# UUID epoch 1582-10-15 00:00:00 and the Unix epoch 1970-01-01 00:00:00. 

timestamp = int(nanoseconds/100) + 0x01b21dd213814000 

if _last_timestamp is not None and timestamp <= _last_timestamp: 

timestamp = _last_timestamp + 1 

_last_timestamp = timestamp 

if clock_seq is None: 

import random 

clock_seq = random.getrandbits(14) # instead of stable storage 

time_low = timestamp & 0xffffffff 

time_mid = (timestamp >> 32) & 0xffff 

time_hi_version = (timestamp >> 48) & 0x0fff 

clock_seq_low = clock_seq & 0xff 

clock_seq_hi_variant = (clock_seq >> 8) & 0x3f 

if node is None: 

node = getnode() 

return UUID(fields=(time_low, time_mid, time_hi_version, 

clock_seq_hi_variant, clock_seq_low, node), version=1) 

 

def uuid3(namespace, name): 

"""Generate a UUID from the MD5 hash of a namespace UUID and a name.""" 

from hashlib import md5 

hash = md5(namespace.bytes + bytes(name, "utf-8")).digest() 

return UUID(bytes=hash[:16], version=3) 

 

def uuid4(): 

"""Generate a random UUID.""" 

return UUID(bytes=os.urandom(16), version=4) 

 

def uuid5(namespace, name): 

"""Generate a UUID from the SHA-1 hash of a namespace UUID and a name.""" 

from hashlib import sha1 

hash = sha1(namespace.bytes + bytes(name, "utf-8")).digest() 

return UUID(bytes=hash[:16], version=5) 

 

# The following standard UUIDs are for use with uuid3() or uuid5(). 

 

NAMESPACE_DNS = UUID('6ba7b810-9dad-11d1-80b4-00c04fd430c8') 

NAMESPACE_URL = UUID('6ba7b811-9dad-11d1-80b4-00c04fd430c8') 

NAMESPACE_OID = UUID('6ba7b812-9dad-11d1-80b4-00c04fd430c8') 

NAMESPACE_X500 = UUID('6ba7b814-9dad-11d1-80b4-00c04fd430c8')