/Lib/uuid.py
Python | 544 lines | 544 code | 0 blank | 0 comment | 0 complexity | 41b61a8c58710c5448e5197a8257a56f MD5 | raw file
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 if _uuid_generate_time and node is clock_seq is None: 483 _buffer = ctypes.create_string_buffer(16) 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 if _uuid_generate_random: 520 _buffer = ctypes.create_string_buffer(16) 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')