Ticket #1180: uuid.py

File uuid.py, 19.8 KB (added by digitalxero@…, 17 years ago)

the uuid file fall back for python 2.3 & 2.4. I put it in django/utils

Line 
1r"""UUID objects (universally unique identifiers) according to RFC 4122.
2
3This module provides immutable UUID objects (class UUID) and the functions
4uuid1(), uuid3(), uuid4(), uuid5() for generating version 1, 3, 4, and 5
5UUIDs as specified in RFC 4122.
6
7If all you want is a unique ID, you should probably call uuid1() or uuid4().
8Note that uuid1() may compromise privacy since it creates a UUID containing
9the computer's network address. uuid4() creates a random UUID.
10
11Typical usage:
12
13 >>> import uuid
14
15 # make a UUID based on the host ID and current time
16 >>> uuid.uuid1()
17 UUID('a8098c1a-f86e-11da-bd1a-00112444be1e')
18
19 # make a UUID using an MD5 hash of a namespace UUID and a name
20 >>> uuid.uuid3(uuid.NAMESPACE_DNS, 'python.org')
21 UUID('6fa459ea-ee8a-3ca4-894e-db77e160355e')
22
23 # make a random UUID
24 >>> uuid.uuid4()
25 UUID('16fd2706-8baf-433b-82eb-8c7fada847da')
26
27 # make a UUID using a SHA-1 hash of a namespace UUID and a name
28 >>> uuid.uuid5(uuid.NAMESPACE_DNS, 'python.org')
29 UUID('886313e1-3b8a-5372-9b90-0c9aee199e5d')
30
31 # make a UUID from a string of hex digits (braces and hyphens ignored)
32 >>> x = uuid.UUID('{00010203-0405-0607-0809-0a0b0c0d0e0f}')
33
34 # convert a UUID to a string of hex digits in standard form
35 >>> str(x)
36 '00010203-0405-0607-0809-0a0b0c0d0e0f'
37
38 # get the raw 16 bytes of the UUID
39 >>> x.bytes
40 '\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f'
41
42 # make a UUID from a 16-byte string
43 >>> uuid.UUID(bytes=x.bytes)
44 UUID('00010203-0405-0607-0809-0a0b0c0d0e0f')
45"""
46
47__author__ = 'Ka-Ping Yee <ping@zesty.ca>'
48
49RESERVED_NCS, RFC_4122, RESERVED_MICROSOFT, RESERVED_FUTURE = [
50 'reserved for NCS compatibility', 'specified in RFC 4122',
51 'reserved for Microsoft compatibility', 'reserved for future definition']
52
53class UUID(object):
54 """Instances of the UUID class represent UUIDs as specified in RFC 4122.
55 UUID objects are immutable, hashable, and usable as dictionary keys.
56 Converting a UUID to a string with str() yields something in the form
57 '12345678-1234-1234-1234-123456789abc'. The UUID constructor accepts
58 five possible forms: a similar string of hexadecimal digits, or a tuple
59 of six integer fields (with 32-bit, 16-bit, 16-bit, 8-bit, 8-bit, and
60 48-bit values respectively) as an argument named 'fields', or a string
61 of 16 bytes (with all the integer fields in big-endian order) as an
62 argument named 'bytes', or a string of 16 bytes (with the first three
63 fields in little-endian order) as an argument named 'bytes_le', or a
64 single 128-bit integer as an argument named 'int'.
65
66 UUIDs have these read-only attributes:
67
68 bytes the UUID as a 16-byte string (containing the six
69 integer fields in big-endian byte order)
70
71 bytes_le the UUID as a 16-byte string (with time_low, time_mid,
72 and time_hi_version in little-endian byte order)
73
74 fields a tuple of the six integer fields of the UUID,
75 which are also available as six individual attributes
76 and two derived attributes:
77
78 time_low the first 32 bits of the UUID
79 time_mid the next 16 bits of the UUID
80 time_hi_version the next 16 bits of the UUID
81 clock_seq_hi_variant the next 8 bits of the UUID
82 clock_seq_low the next 8 bits of the UUID
83 node the last 48 bits of the UUID
84
85 time the 60-bit timestamp
86 clock_seq the 14-bit sequence number
87
88 hex the UUID as a 32-character hexadecimal string
89
90 int the UUID as a 128-bit integer
91
92 urn the UUID as a URN as specified in RFC 4122
93
94 variant the UUID variant (one of the constants RESERVED_NCS,
95 RFC_4122, RESERVED_MICROSOFT, or RESERVED_FUTURE)
96
97 version the UUID version number (1 through 5, meaningful only
98 when the variant is RFC_4122)
99 """
100
101 def __init__(self, hex=None, bytes=None, bytes_le=None, fields=None,
102 int=None, version=None):
103 r"""Create a UUID from either a string of 32 hexadecimal digits,
104 a string of 16 bytes as the 'bytes' argument, a string of 16 bytes
105 in little-endian order as the 'bytes_le' argument, a tuple of six
106 integers (32-bit time_low, 16-bit time_mid, 16-bit time_hi_version,
107 8-bit clock_seq_hi_variant, 8-bit clock_seq_low, 48-bit node) as
108 the 'fields' argument, or a single 128-bit integer as the 'int'
109 argument. When a string of hex digits is given, curly braces,
110 hyphens, and a URN prefix are all optional. For example, these
111 expressions all yield the same UUID:
112
113 UUID('{12345678-1234-5678-1234-567812345678}')
114 UUID('12345678123456781234567812345678')
115 UUID('urn:uuid:12345678-1234-5678-1234-567812345678')
116 UUID(bytes='\x12\x34\x56\x78'*4)
117 UUID(bytes_le='\x78\x56\x34\x12\x34\x12\x78\x56' +
118 '\x12\x34\x56\x78\x12\x34\x56\x78')
119 UUID(fields=(0x12345678, 0x1234, 0x5678, 0x12, 0x34, 0x567812345678))
120 UUID(int=0x12345678123456781234567812345678)
121
122 Exactly one of 'hex', 'bytes', 'bytes_le', 'fields', or 'int' must
123 be given. The 'version' argument is optional; if given, the resulting
124 UUID will have its variant and version set according to RFC 4122,
125 overriding the given 'hex', 'bytes', 'bytes_le', 'fields', or 'int'.
126 """
127
128 if [hex, bytes, bytes_le, fields, int].count(None) != 4:
129 raise TypeError('need one of hex, bytes, bytes_le, fields, or int')
130 if hex is not None:
131 hex = hex.replace('urn:', '').replace('uuid:', '')
132 hex = hex.strip('{}').replace('-', '')
133 if len(hex) != 32:
134 raise ValueError('badly formed hexadecimal UUID string')
135 int = long(hex, 16)
136 if bytes_le is not None:
137 if len(bytes_le) != 16:
138 raise ValueError('bytes_le is not a 16-char string')
139 bytes = (bytes_le[3] + bytes_le[2] + bytes_le[1] + bytes_le[0] +
140 bytes_le[5] + bytes_le[4] + bytes_le[7] + bytes_le[6] +
141 bytes_le[8:])
142 if bytes is not None:
143 if len(bytes) != 16:
144 raise ValueError('bytes is not a 16-char string')
145 int = long(('%02x'*16) % tuple(map(ord, bytes)), 16)
146 if fields is not None:
147 if len(fields) != 6:
148 raise ValueError('fields is not a 6-tuple')
149 (time_low, time_mid, time_hi_version,
150 clock_seq_hi_variant, clock_seq_low, node) = fields
151 if not 0 <= time_low < 1<<32L:
152 raise ValueError('field 1 out of range (need a 32-bit value)')
153 if not 0 <= time_mid < 1<<16L:
154 raise ValueError('field 2 out of range (need a 16-bit value)')
155 if not 0 <= time_hi_version < 1<<16L:
156 raise ValueError('field 3 out of range (need a 16-bit value)')
157 if not 0 <= clock_seq_hi_variant < 1<<8L:
158 raise ValueError('field 4 out of range (need an 8-bit value)')
159 if not 0 <= clock_seq_low < 1<<8L:
160 raise ValueError('field 5 out of range (need an 8-bit value)')
161 if not 0 <= node < 1<<48L:
162 raise ValueError('field 6 out of range (need a 48-bit value)')
163 clock_seq = (clock_seq_hi_variant << 8L) | clock_seq_low
164 int = ((time_low << 96L) | (time_mid << 80L) |
165 (time_hi_version << 64L) | (clock_seq << 48L) | node)
166 if int is not None:
167 if not 0 <= int < 1<<128L:
168 raise ValueError('int is out of range (need a 128-bit value)')
169 if version is not None:
170 if not 1 <= version <= 5:
171 raise ValueError('illegal version number')
172 # Set the variant to RFC 4122.
173 int &= ~(0xc000 << 48L)
174 int |= 0x8000 << 48L
175 # Set the version number.
176 int &= ~(0xf000 << 64L)
177 int |= version << 76L
178 self.__dict__['int'] = int
179
180 def __cmp__(self, other):
181 if isinstance(other, UUID):
182 return cmp(self.int, other.int)
183 return NotImplemented
184
185 def __hash__(self):
186 return hash(self.int)
187
188 def __int__(self):
189 return self.int
190
191 def __repr__(self):
192 return 'UUID(%r)' % str(self)
193
194 def __setattr__(self, name, value):
195 raise TypeError('UUID objects are immutable')
196
197 def __str__(self):
198 hex = '%032x' % self.int
199 return '%s-%s-%s-%s-%s' % (
200 hex[:8], hex[8:12], hex[12:16], hex[16:20], hex[20:])
201
202 def get_bytes(self):
203 bytes = ''
204 for shift in range(0, 128, 8):
205 bytes = chr((self.int >> shift) & 0xff) + bytes
206 return bytes
207
208 bytes = property(get_bytes)
209
210 def get_bytes_le(self):
211 bytes = self.bytes
212 return (bytes[3] + bytes[2] + bytes[1] + bytes[0] +
213 bytes[5] + bytes[4] + bytes[7] + bytes[6] + bytes[8:])
214
215 bytes_le = property(get_bytes_le)
216
217 def get_fields(self):
218 return (self.time_low, self.time_mid, self.time_hi_version,
219 self.clock_seq_hi_variant, self.clock_seq_low, self.node)
220
221 fields = property(get_fields)
222
223 def get_time_low(self):
224 return self.int >> 96L
225
226 time_low = property(get_time_low)
227
228 def get_time_mid(self):
229 return (self.int >> 80L) & 0xffff
230
231 time_mid = property(get_time_mid)
232
233 def get_time_hi_version(self):
234 return (self.int >> 64L) & 0xffff
235
236 time_hi_version = property(get_time_hi_version)
237
238 def get_clock_seq_hi_variant(self):
239 return (self.int >> 56L) & 0xff
240
241 clock_seq_hi_variant = property(get_clock_seq_hi_variant)
242
243 def get_clock_seq_low(self):
244 return (self.int >> 48L) & 0xff
245
246 clock_seq_low = property(get_clock_seq_low)
247
248 def get_time(self):
249 return (((self.time_hi_version & 0x0fffL) << 48L) |
250 (self.time_mid << 32L) | self.time_low)
251
252 time = property(get_time)
253
254 def get_clock_seq(self):
255 return (((self.clock_seq_hi_variant & 0x3fL) << 8L) |
256 self.clock_seq_low)
257
258 clock_seq = property(get_clock_seq)
259
260 def get_node(self):
261 return self.int & 0xffffffffffff
262
263 node = property(get_node)
264
265 def get_hex(self):
266 return '%032x' % self.int
267
268 hex = property(get_hex)
269
270 def get_urn(self):
271 return 'urn:uuid:' + str(self)
272
273 urn = property(get_urn)
274
275 def get_variant(self):
276 if not self.int & (0x8000 << 48L):
277 return RESERVED_NCS
278 elif not self.int & (0x4000 << 48L):
279 return RFC_4122
280 elif not self.int & (0x2000 << 48L):
281 return RESERVED_MICROSOFT
282 else:
283 return RESERVED_FUTURE
284
285 variant = property(get_variant)
286
287 def get_version(self):
288 # The version bits are only meaningful for RFC 4122 UUIDs.
289 if self.variant == RFC_4122:
290 return int((self.int >> 76L) & 0xf)
291
292 version = property(get_version)
293
294def _find_mac(command, args, hw_identifiers, get_index):
295 import os
296 for dir in ['', '/sbin/', '/usr/sbin']:
297 executable = os.path.join(dir, command)
298 if not os.path.exists(executable):
299 continue
300
301 try:
302 # LC_ALL to get English output, 2>/dev/null to
303 # prevent output on stderr
304 cmd = 'LC_ALL=C %s %s 2>/dev/null' % (executable, args)
305 pipe = os.popen(cmd)
306 except IOError:
307 continue
308
309 for line in pipe:
310 words = line.lower().split()
311 for i in range(len(words)):
312 if words[i] in hw_identifiers:
313 return int(words[get_index(i)].replace(':', ''), 16)
314 return None
315
316def _ifconfig_getnode():
317 """Get the hardware address on Unix by running ifconfig."""
318
319 # This works on Linux ('' or '-a'), Tru64 ('-av'), but not all Unixes.
320 for args in ('', '-a', '-av'):
321 mac = _find_mac('ifconfig', args, ['hwaddr', 'ether'], lambda i: i+1)
322 if mac:
323 return mac
324
325 import socket
326 ip_addr = socket.gethostbyname(socket.gethostname())
327
328 # Try getting the MAC addr from arp based on our IP address (Solaris).
329 mac = _find_mac('arp', '-an', [ip_addr], lambda i: -1)
330 if mac:
331 return mac
332
333 # This might work on HP-UX.
334 mac = _find_mac('lanscan', '-ai', ['lan0'], lambda i: 0)
335 if mac:
336 return mac
337
338 return None
339
340def _ipconfig_getnode():
341 """Get the hardware address on Windows by running ipconfig.exe."""
342 import os, re
343 dirs = ['', r'c:\windows\system32', r'c:\winnt\system32']
344 try:
345 import ctypes
346 buffer = ctypes.create_string_buffer(300)
347 ctypes.windll.kernel32.GetSystemDirectoryA(buffer, 300)
348 dirs.insert(0, buffer.value.decode('mbcs'))
349 except:
350 pass
351 for dir in dirs:
352 try:
353 pipe = os.popen(os.path.join(dir, 'ipconfig') + ' /all')
354 except IOError:
355 continue
356 for line in pipe:
357 value = line.split(':')[-1].strip().lower()
358 if re.match('([0-9a-f][0-9a-f]-){5}[0-9a-f][0-9a-f]', value):
359 return int(value.replace('-', ''), 16)
360
361def _netbios_getnode():
362 """Get the hardware address on Windows using NetBIOS calls.
363 See http://support.microsoft.com/kb/118623 for details."""
364 import win32wnet, netbios
365 ncb = netbios.NCB()
366 ncb.Command = netbios.NCBENUM
367 ncb.Buffer = adapters = netbios.LANA_ENUM()
368 adapters._pack()
369 if win32wnet.Netbios(ncb) != 0:
370 return
371 adapters._unpack()
372 for i in range(adapters.length):
373 ncb.Reset()
374 ncb.Command = netbios.NCBRESET
375 ncb.Lana_num = ord(adapters.lana[i])
376 if win32wnet.Netbios(ncb) != 0:
377 continue
378 ncb.Reset()
379 ncb.Command = netbios.NCBASTAT
380 ncb.Lana_num = ord(adapters.lana[i])
381 ncb.Callname = '*'.ljust(16)
382 ncb.Buffer = status = netbios.ADAPTER_STATUS()
383 if win32wnet.Netbios(ncb) != 0:
384 continue
385 status._unpack()
386 bytes = map(ord, status.adapter_address)
387 return ((bytes[0]<<40L) + (bytes[1]<<32L) + (bytes[2]<<24L) +
388 (bytes[3]<<16L) + (bytes[4]<<8L) + bytes[5])
389
390# Thanks to Thomas Heller for ctypes and for his help with its use here.
391
392# If ctypes is available, use it to find system routines for UUID generation.
393_uuid_generate_random = _uuid_generate_time = _UuidCreate = None
394try:
395 import ctypes, ctypes.util
396
397 # The uuid_generate_* routines are provided by libuuid on at least
398 # Linux and FreeBSD, and provided by libc on Mac OS X.
399 for libname in ['uuid', 'c']:
400 try:
401 lib = ctypes.CDLL(ctypes.util.find_library(libname))
402 except:
403 continue
404 if hasattr(lib, 'uuid_generate_random'):
405 _uuid_generate_random = lib.uuid_generate_random
406 if hasattr(lib, 'uuid_generate_time'):
407 _uuid_generate_time = lib.uuid_generate_time
408
409 # On Windows prior to 2000, UuidCreate gives a UUID containing the
410 # hardware address. On Windows 2000 and later, UuidCreate makes a
411 # random UUID and UuidCreateSequential gives a UUID containing the
412 # hardware address. These routines are provided by the RPC runtime.
413 # NOTE: at least on Tim's WinXP Pro SP2 desktop box, while the last
414 # 6 bytes returned by UuidCreateSequential are fixed, they don't appear
415 # to bear any relationship to the MAC address of any network device
416 # on the box.
417 try:
418 lib = ctypes.windll.rpcrt4
419 except:
420 lib = None
421 _UuidCreate = getattr(lib, 'UuidCreateSequential',
422 getattr(lib, 'UuidCreate', None))
423except:
424 pass
425
426def _unixdll_getnode():
427 """Get the hardware address on Unix using ctypes."""
428 _buffer = ctypes.create_string_buffer(16)
429 _uuid_generate_time(_buffer)
430 return UUID(bytes=_buffer.raw).node
431
432def _windll_getnode():
433 """Get the hardware address on Windows using ctypes."""
434 _buffer = ctypes.create_string_buffer(16)
435 if _UuidCreate(_buffer) == 0:
436 return UUID(bytes=_buffer.raw).node
437
438def _random_getnode():
439 """Get a random node ID, with eighth bit set as suggested by RFC 4122."""
440 import random
441 return random.randrange(0, 1<<48L) | 0x010000000000L
442
443_node = None
444
445def getnode():
446 """Get the hardware address as a 48-bit positive integer.
447
448 The first time this runs, it may launch a separate program, which could
449 be quite slow. If all attempts to obtain the hardware address fail, we
450 choose a random 48-bit number with its eighth bit set to 1 as recommended
451 in RFC 4122.
452 """
453
454 global _node
455 if _node is not None:
456 return _node
457
458 import sys
459 if sys.platform == 'win32':
460 getters = [_windll_getnode, _netbios_getnode, _ipconfig_getnode]
461 else:
462 getters = [_unixdll_getnode, _ifconfig_getnode]
463
464 for getter in getters + [_random_getnode]:
465 try:
466 _node = getter()
467 except:
468 continue
469 if _node is not None:
470 return _node
471
472_last_timestamp = None
473
474def uuid1(node=None, clock_seq=None):
475 """Generate a UUID from a host ID, sequence number, and the current time.
476 If 'node' is not given, getnode() is used to obtain the hardware
477 address. If 'clock_seq' is given, it is used as the sequence number;
478 otherwise a random 14-bit sequence number is chosen."""
479
480 # When the system provides a version-1 UUID generator, use it (but don't
481 # use UuidCreate here because its UUIDs don't conform to RFC 4122).
482 _buffer = ctypes.create_string_buffer(16)
483 if _uuid_generate_time and node is clock_seq is None:
484 _uuid_generate_time(_buffer)
485 return UUID(bytes=_buffer.raw)
486
487 global _last_timestamp
488 import time
489 nanoseconds = int(time.time() * 1e9)
490 # 0x01b21dd213814000 is the number of 100-ns intervals between the
491 # UUID epoch 1582-10-15 00:00:00 and the Unix epoch 1970-01-01 00:00:00.
492 timestamp = int(nanoseconds/100) + 0x01b21dd213814000L
493 if timestamp <= _last_timestamp:
494 timestamp = _last_timestamp + 1
495 _last_timestamp = timestamp
496 if clock_seq is None:
497 import random
498 clock_seq = random.randrange(1<<14L) # instead of stable storage
499 time_low = timestamp & 0xffffffffL
500 time_mid = (timestamp >> 32L) & 0xffffL
501 time_hi_version = (timestamp >> 48L) & 0x0fffL
502 clock_seq_low = clock_seq & 0xffL
503 clock_seq_hi_variant = (clock_seq >> 8L) & 0x3fL
504 if node is None:
505 node = getnode()
506 return UUID(fields=(time_low, time_mid, time_hi_version,
507 clock_seq_hi_variant, clock_seq_low, node), version=1)
508
509def uuid3(namespace, name):
510 """Generate a UUID from the MD5 hash of a namespace UUID and a name."""
511 from hashlib import md5
512 hash = md5(namespace.bytes + name).digest()
513 return UUID(bytes=hash[:16], version=3)
514
515def uuid4():
516 """Generate a random UUID."""
517
518 # When the system provides a version-4 UUID generator, use it.
519 _buffer = ctypes.create_string_buffer(16)
520 if _uuid_generate_random:
521 _uuid_generate_random(_buffer)
522 return UUID(bytes=_buffer.raw)
523
524 # Otherwise, get randomness from urandom or the 'random' module.
525 try:
526 import os
527 return UUID(bytes=os.urandom(16), version=4)
528 except:
529 import random
530 bytes = [chr(random.randrange(256)) for i in range(16)]
531 return UUID(bytes=bytes, version=4)
532
533def uuid5(namespace, name):
534 """Generate a UUID from the SHA-1 hash of a namespace UUID and a name."""
535 from hashlib import sha1
536 hash = sha1(namespace.bytes + name).digest()
537 return UUID(bytes=hash[:16], version=5)
538
539# The following standard UUIDs are for use with uuid3() or uuid5().
540
541NAMESPACE_DNS = UUID('6ba7b810-9dad-11d1-80b4-00c04fd430c8')
542NAMESPACE_URL = UUID('6ba7b811-9dad-11d1-80b4-00c04fd430c8')
543NAMESPACE_OID = UUID('6ba7b812-9dad-11d1-80b4-00c04fd430c8')
544NAMESPACE_X500 = UUID('6ba7b814-9dad-11d1-80b4-00c04fd430c8')
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