client-libraries/python/redis.py

   1 #!/usr/bin/python
   2
   3 """ redis.py - A client for the Redis daemon.
   4
   5 """
   6
   7 __author__ = "Ludovico Magnocavallo <ludo\x40qix\x2eit>"
   8 __copyright__ = "Copyright 2009, Ludovico Magnocavallo"
   9 __license__ = "MIT"
  10 __version__ = "0.5"
  11 __revision__ = "$LastChangedRevision: 175 $"[22:-2]
  12 __date__ = "$LastChangedDate: 2009-03-17 16:15:55 +0100 (Mar, 17 Mar 2009) $"[18:-2]
  13
  14
  15 # TODO: Redis._get_multi_response
  16
  17
  18 import socket
  19
  20
  21 BUFSIZE = 4096
  22
  23
  24 class RedisError(Exception): pass
  25 class ConnectionError(RedisError): pass
  26 class ResponseError(RedisError): pass
  27 class InvalidResponse(RedisError): pass
  28 class InvalidData(RedisError): pass
  29
  30
  31 class Redis(object):
  32     """The main Redis client.
  33     """
  34
  35     def __init__(self, host=None, port=None, timeout=None, db=None):
  36         self.host = host or 'localhost'
  37         self.port = port or 6379
  38         if timeout:
  39             socket.setdefaulttimeout(timeout)
  40         self._sock = None
  41         self._fp = None
  42         self.db = db
  43
  44     def _write(self, s):
  45         """
  46         >>> r = Redis(db=9)
  47         >>> r.connect()
  48         >>> r._sock.close()
  49         >>> try:
  50         ...     r._write('pippo')
  51         ... except ConnectionError, e:
  52         ...     print e
  53         Error 9 while writing to socket. Bad file descriptor.
  54         >>>
  55         >>>
  56         """
  57         try:
  58             self._sock.sendall(s)
  59         except socket.error, e:
  60             if e.args[0] == 32:
  61                 # broken pipe
  62                 self.disconnect()
  63             raise ConnectionError("Error %s while writing to socket. %s." % tuple(e.args))
  64
  65     def _read(self):
  66         try:
  67             return self._fp.readline()
  68         except socket.error, e:
  69             if e.args and e.args[0] == errno.EAGAIN:
  70                 return
  71             self.disconnect()
  72             raise ConnectionError("Error %s while reading from socket. %s." % tuple(e.args))
  73         if not data:
  74             self.disconnect()
  75             raise ConnectionError("Socket connection closed when reading.")
  76         return data
  77
  78     def ping(self):
  79         """
  80         >>> r = Redis(db=9)
  81         >>> r.ping()
  82         'PONG'
  83         >>>
  84         """
  85         self.connect()
  86         self._write('PING\r\n')
  87         return self.get_response()
  88
  89     def set(self, name, value, preserve=False):
  90         """
  91         >>> r = Redis(db=9)
  92         >>> r.set('a', 'pippo')
  93         'OK'
  94         >>> try:
  95         ...     r.set('a', u'pippo \u3235')
  96         ... except InvalidData, e:
  97         ...     print e
  98         Error encoding unicode value for key 'a': 'ascii' codec can't encode character u'\u3235' in position 15: ordinal not in range(128).
  99         >>> r.set('b', 105.2)
 100         'OK'
 101         >>> r.set('b', 'xxx', preserve=True)
 102         0
 103         >>> r.get('b')
 104         '105.2'
 105         >>>
 106         """
 107         self.connect()
 108         # the following will raise an error for unicode values that can't be encoded to ascii
 109         # we could probably add an 'encoding' arg to init, but then what do we do with get()?
 110         # convert back to unicode? and what about ints, or pickled values?
 111         try:
 112             value = value if isinstance(value, basestring) else str(value)
 113             self._write('%s %s %s\r\n%s\r\n' % (
 114                 'SETNX' if preserve else 'SET', name, len(value), value
 115             ))
 116         except UnicodeEncodeError, e:
 117             raise InvalidData("Error encoding unicode value for key '%s': %s." % (name, e))
 118         return self.get_response()
 119
 120     def get(self, name):
 121         """
 122         >>> r = Redis(db=9)
 123         >>> r.set('a', 'pippo'), r.set('b', 15), r.set('c', ' \\r\\naaa\\nbbb\\r\\ncccc\\nddd\\r\\n '), r.set('d', '\\r\\n')
 124         ('OK', 'OK', 'OK', 'OK')
 125         >>> r.get('a')
 126         'pippo'
 127         >>> r.get('b')
 128         '15'
 129         >>> r.get('d')
 130         '\\r\\n'
 131         >>> r.get('b')
 132         '15'
 133         >>> r.get('c')
 134         ' \\r\\naaa\\nbbb\\r\\ncccc\\nddd\\r\\n '
 135         >>> r.get('c')
 136         ' \\r\\naaa\\nbbb\\r\\ncccc\\nddd\\r\\n '
 137         >>> r.get('ajhsd')
 138         >>>
 139         """
 140         self.connect()
 141         self._write('GET %s\r\n' % name)
 142         return self.get_response()
 143
 144     def mget(self, *args):
 145         """
 146         >>> r = Redis(db=9)
 147         >>> r.set('a', 'pippo'), r.set('b', 15), r.set('c', '\\r\\naaa\\nbbb\\r\\ncccc\\nddd\\r\\n'), r.set('d', '\\r\\n')
 148         ('OK', 'OK', 'OK', 'OK')
 149         >>> r.mget('a', 'b', 'c', 'd')
 150         ['pippo', '15', '\\r\\naaa\\nbbb\\r\\ncccc\\nddd\\r\\n', '\\r\\n']
 151         >>>
 152         """
 153         self.connect()
 154         self._write('MGET %s\r\n' % ' '.join(args))
 155         return self.get_response()
 156
 157     def incr(self, name, amount=1):
 158         """
 159         >>> r = Redis(db=9)
 160         >>> r.delete('a')
 161         1
 162         >>> r.incr('a')
 163         1
 164         >>> r.incr('a')
 165         2
 166         >>> r.incr('a', 2)
 167         4
 168         >>>
 169         """
 170         self.connect()
 171         if amount == 1:
 172             self._write('INCR %s\r\n' % name)
 173         else:
 174             self._write('INCRBY %s %s\r\n' % (name, amount))
 175         return self.get_response()
 176
 177     def decr(self, name, amount=1):
 178         """
 179         >>> r = Redis(db=9)
 180         >>> if r.get('a'):
 181         ...     r.delete('a')
 182         ... else:
 183         ...     print 1
 184         1
 185         >>> r.decr('a')
 186         -1
 187         >>> r.decr('a')
 188         -2
 189         >>> r.decr('a', 5)
 190         -7
 191         >>>
 192         """
 193         self.connect()
 194         if amount == 1:
 195             self._write('DECR %s\r\n' % name)
 196         else:
 197             self._write('DECRBY %s %s\r\n' % (name, amount))
 198         return self.get_response()
 199
 200     def exists(self, name):
 201         """
 202         >>> r = Redis(db=9)
 203         >>> r.exists('dsjhfksjdhfkdsjfh')
 204         0
 205         >>> r.set('a', 'a')
 206         'OK'
 207         >>> r.exists('a')
 208         1
 209         >>>
 210         """
 211         self.connect()
 212         self._write('EXISTS %s\r\n' % name)
 213         return self.get_response()
 214
 215     def delete(self, name):
 216         """
 217         >>> r = Redis(db=9)
 218         >>> r.delete('dsjhfksjdhfkdsjfh')
 219         0
 220         >>> r.set('a', 'a')
 221         'OK'
 222         >>> r.delete('a')
 223         1
 224         >>> r.exists('a')
 225         0
 226         >>> r.delete('a')
 227         0
 228         >>>
 229         """
 230         self.connect()
 231         self._write('DEL %s\r\n' % name)
 232         return self.get_response()
 233
 234     def key_type(self, name):
 235         """
 236         Not yet implemented.
 237         """
 238         self.connect()
 239         self._write('TYPE %s\r\n' % name)
 240         return self.get_response()
 241
 242     def keys(self, pattern):
 243         """
 244         >>> r = Redis(db=9)
 245         >>> r.flush()
 246         'OK'
 247         >>> r.set('a', 'a')
 248         'OK'
 249         >>> r.keys('a*')
 250         ['a']
 251         >>> r.set('a2', 'a')
 252         'OK'
 253         >>> r.keys('a*')
 254         ['a', 'a2']
 255         >>> r.delete('a2')
 256         1
 257         >>> r.keys('sjdfhskjh*')
 258         []
 259         >>>
 260         """
 261         self.connect()
 262         self._write('KEYS %s\r\n' % pattern)
 263         return self.get_response().split()
 264
 265     def randomkey(self):
 266         """
 267         >>> r = Redis(db=9)
 268         >>> r.set('a', 'a')
 269         'OK'
 270         >>> isinstance(r.randomkey(), str)
 271         True
 272         >>>
 273         """
 274         #raise NotImplementedError("Implemented but buggy, do not use.")
 275         self.connect()
 276         self._write('RANDOMKEY\r\n')
 277         return self.get_response()
 278
 279     def rename(self, src, dst, preserve=False):
 280         """
 281         >>> r = Redis(db=9)
 282         >>> try:
 283         ...     r.rename('a', 'a')
 284         ... except ResponseError, e:
 285         ...     print e
 286         source and destination objects are the same
 287         >>> r.rename('a', 'b')
 288         'OK'
 289         >>> try:
 290         ...     r.rename('a', 'b')
 291         ... except ResponseError, e:
 292         ...     print e
 293         no such key
 294         >>> r.set('a', 1)
 295         'OK'
 296         >>> r.rename('b', 'a', preserve=True)
 297         0
 298         >>>
 299         """
 300         self.connect()
 301         if preserve:
 302             self._write('RENAMENX %s %s\r\n' % (src, dst))
 303             return self.get_response()
 304         else:
 305             self._write('RENAME %s %s\r\n' % (src, dst))
 306             return self.get_response() #.strip()
 307
 308     def push(self, name, value, tail=False):
 309         """
 310         >>> r = Redis(db=9)
 311         >>> r.delete('l')
 312         1
 313         >>> r.push('l', 'a')
 314         'OK'
 315         >>> r.set('a', 'a')
 316         'OK'
 317         >>> try:
 318         ...     r.push('a', 'a')
 319         ... except ResponseError, e:
 320         ...     print e
 321         Operation against a key holding the wrong kind of value
 322         >>>
 323         """
 324         self.connect()
 325         # same considerations on unicode as in set() apply here
 326         try:
 327             value = value if isinstance(value, basestring) else str(value)
 328             self._write('%s %s %s\r\n%s\r\n' % (
 329                 'LPUSH' if tail else 'RPUSH', name, len(value), value
 330             ))
 331         except UnicodeEncodeError, e:
 332             raise InvalidData("Error encoding unicode value for element in list '%s': %s." % (name, e))
 333         return self.get_response()
 334
 335     def llen(self, name):
 336         """
 337         >>> r = Redis(db=9)
 338         >>> r.delete('l')
 339         1
 340         >>> r.push('l', 'a')
 341         'OK'
 342         >>> r.llen('l')
 343         1
 344         >>> r.push('l', 'a')
 345         'OK'
 346         >>> r.llen('l')
 347         2
 348         >>>
 349         """
 350         self.connect()
 351         self._write('LLEN %s\r\n' % name)
 352         return self.get_response()
 353
 354     def lrange(self, name, start, end):
 355         """
 356         >>> r = Redis(db=9)
 357         >>> r.delete('l')
 358         1
 359         >>> r.lrange('l', 0, 1)
 360         []
 361         >>> r.push('l', 'aaa')
 362         'OK'
 363         >>> r.lrange('l', 0, 1)
 364         ['aaa']
 365         >>> r.push('l', 'bbb')
 366         'OK'
 367         >>> r.lrange('l', 0, 0)
 368         ['aaa']
 369         >>> r.lrange('l', 0, 1)
 370         ['aaa', 'bbb']
 371         >>> r.lrange('l', -1, 0)
 372         []
 373         >>> r.lrange('l', -1, -1)
 374         ['bbb']
 375         >>>
 376         """
 377         self.connect()
 378         self._write('LRANGE %s %s %s\r\n' % (name, start, end))
 379         return self.get_response()
 380
 381     def ltrim(self, name, start, end):
 382         """
 383         >>> r = Redis(db=9)
 384         >>> r.delete('l')
 385         1
 386         >>> try:
 387         ...     r.ltrim('l', 0, 1)
 388         ... except ResponseError, e:
 389         ...     print e
 390         no such key
 391         >>> r.push('l', 'aaa')
 392         'OK'
 393         >>> r.push('l', 'bbb')
 394         'OK'
 395         >>> r.push('l', 'ccc')
 396         'OK'
 397         >>> r.ltrim('l', 0, 1)
 398         'OK'
 399         >>> r.llen('l')
 400         2
 401         >>> r.ltrim('l', 99, 95)
 402         'OK'
 403         >>> r.llen('l')
 404         0
 405         >>>
 406         """
 407         self.connect()
 408         self._write('LTRIM %s %s %s\r\n' % (name, start, end))
 409         return self.get_response()
 410
 411     def lindex(self, name, index):
 412         """
 413         >>> r = Redis(db=9)
 414         >>> res = r.delete('l')
 415         >>> r.lindex('l', 0)
 416         >>> r.push('l', 'aaa')
 417         'OK'
 418         >>> r.lindex('l', 0)
 419         'aaa'
 420         >>> r.lindex('l', 2)
 421         >>> r.push('l', 'ccc')
 422         'OK'
 423         >>> r.lindex('l', 1)
 424         'ccc'
 425         >>> r.lindex('l', -1)
 426         'ccc'
 427         >>>
 428         """
 429         self.connect()
 430         self._write('LINDEX %s %s\r\n' % (name, index))
 431         return self.get_response()
 432
 433     def pop(self, name, tail=False):
 434         """
 435         >>> r = Redis(db=9)
 436         >>> r.delete('l')
 437         1
 438         >>> r.pop('l')
 439         >>> r.push('l', 'aaa')
 440         'OK'
 441         >>> r.push('l', 'bbb')
 442         'OK'
 443         >>> r.pop('l')
 444         'aaa'
 445         >>> r.pop('l')
 446         'bbb'
 447         >>> r.pop('l')
 448         >>> r.push('l', 'aaa')
 449         'OK'
 450         >>> r.push('l', 'bbb')
 451         'OK'
 452         >>> r.pop('l', tail=True)
 453         'bbb'
 454         >>> r.pop('l')
 455         'aaa'
 456         >>> r.pop('l')
 457         >>>
 458         """
 459         self.connect()
 460         self._write('%s %s\r\n' % ('RPOP' if tail else 'LPOP', name))
 461         return self.get_response()
 462
 463     def lset(self, name, index, value):
 464         """
 465         >>> r = Redis(db=9)
 466         >>> r.delete('l')
 467         1
 468         >>> try:
 469         ...     r.lset('l', 0, 'a')
 470         ... except ResponseError, e:
 471         ...     print e
 472         no such key
 473         >>> r.push('l', 'aaa')
 474         'OK'
 475         >>> try:
 476         ...     r.lset('l', 1, 'a')
 477         ... except ResponseError, e:
 478         ...     print e
 479         index out of range
 480         >>> r.lset('l', 0, 'bbb')
 481         'OK'
 482         >>> r.lrange('l', 0, 1)
 483         ['bbb']
 484         >>>
 485         """
 486         self.connect()
 487         try:
 488             value = value if isinstance(value, basestring) else str(value)
 489             self._write('LSET %s %s %s\r\n%s\r\n' % (
 490                 name, index, len(value), value
 491             ))
 492         except UnicodeEncodeError, e:
 493             raise InvalidData("Error encoding unicode value for element %s in list '%s': %s." % (index, name, e))
 494         return self.get_response()
 495
 496     def lrem(self, name, value, num=0):
 497         """
 498         >>> r = Redis(db=9)
 499         >>> r.delete('l')
 500         1
 501         >>> r.push('l', 'aaa')
 502         'OK'
 503         >>> r.push('l', 'bbb')
 504         'OK'
 505         >>> r.push('l', 'aaa')
 506         'OK'
 507         >>> r.lrem('l', 'aaa')
 508         2
 509         >>> r.lrange('l', 0, 10)
 510         ['bbb']
 511         >>> r.push('l', 'aaa')
 512         'OK'
 513         >>> r.push('l', 'aaa')
 514         'OK'
 515         >>> r.lrem('l', 'aaa', 1)
 516         1
 517         >>> r.lrem('l', 'aaa', 1)
 518         1
 519         >>> r.lrem('l', 'aaa', 1)
 520         0
 521         >>>
 522         """
 523         self.connect()
 524         try:
 525             value = value if isinstance(value, basestring) else str(value)
 526             self._write('LREM %s %s %s\r\n%s\r\n' % (
 527                 name, num, len(value), value
 528             ))
 529         except UnicodeEncodeError, e:
 530             raise InvalidData("Error encoding unicode value for element %s in list '%s': %s." % (index, name, e))
 531         return self.get_response()
 532
 533     def sort(self, name, by=None, get=None, start=None, num=None, desc=False, alpha=False):
 534         """
 535         >>> r = Redis(db=9)
 536         >>> r.delete('l')
 537         1
 538         >>> r.push('l', 'ccc')
 539         'OK'
 540         >>> r.push('l', 'aaa')
 541         'OK'
 542         >>> r.push('l', 'ddd')
 543         'OK'
 544         >>> r.push('l', 'bbb')
 545         'OK'
 546         >>> r.sort('l', alpha=True)
 547         ['aaa', 'bbb', 'ccc', 'ddd']
 548         >>> r.delete('l')
 549         1
 550         >>> for i in range(1, 5):
 551         ...     res = r.push('l', 1.0 / i)
 552         >>> r.sort('l')
 553         ['0.25', '0.333333333333', '0.5', '1.0']
 554         >>> r.sort('l', desc=True)
 555         ['1.0', '0.5', '0.333333333333', '0.25']
 556         >>> r.sort('l', desc=True, start=2, num=1)
 557         ['0.333333333333']
 558         >>> r.set('weight_0.5', 10)
 559         'OK'
 560         >>> r.sort('l', desc=True, by='weight_*')
 561         ['0.5', '1.0', '0.333333333333', '0.25']
 562         >>> for i in r.sort('l', desc=True):
 563         ...     res = r.set('test_%s' % i, 100 - float(i))
 564         >>> r.sort('l', desc=True, get='test_*')
 565         ['99.0', '99.5', '99.6666666667', '99.75']
 566         >>> r.sort('l', desc=True, by='weight_*', get='test_*')
 567         ['99.5', '99.0', '99.6666666667', '99.75']
 568         >>> r.sort('l', desc=True, by='weight_*', get='missing_*')
 569         [None, None, None, None]
 570         >>>
 571         """
 572         stmt = ['SORT', name]
 573         if by:
 574             stmt.append("BY %s" % by)
 575         if start and num:
 576             stmt.append("LIMIT %s %s" % (start, num))
 577         if get is None:
 578             pass
 579         elif isinstance(get, basestring):
 580             stmt.append("GET %s" % get)
 581         elif isinstance(get, list) or isinstance(get, tuple):
 582             for g in get:
 583                 stmt.append("GET %s" % g)
 584         else:
 585             raise RedisError("Invalid parameter 'get' for Redis sort")
 586         if desc:
 587             stmt.append("DESC")
 588         if alpha:
 589             stmt.append("ALPHA")
 590         self.connect()
 591         self._write(' '.join(stmt + ["\r\n"]))
 592         return self.get_response()
 593
 594     def sadd(self, name, value):
 595         """
 596         >>> r = Redis(db=9)
 597         >>> res = r.delete('s')
 598         >>> r.sadd('s', 'a')
 599         1
 600         >>> r.sadd('s', 'b')
 601         1
 602         >>>
 603         """
 604         self.connect()
 605         # same considerations on unicode as in set() apply here
 606         try:
 607             value = value if isinstance(value, basestring) else str(value)
 608             self._write('SADD %s %s\r\n%s\r\n' % (
 609                 name, len(value), value
 610             ))
 611         except UnicodeEncodeError, e:
 612             raise InvalidData("Error encoding unicode value for element in set '%s': %s." % (name, e))
 613         return self.get_response()
 614
 615     def srem(self, name, value):
 616         """
 617         >>> r = Redis(db=9)
 618         >>> r.delete('s')
 619         1
 620         >>> r.srem('s', 'aaa')
 621         0
 622         >>> r.sadd('s', 'b')
 623         1
 624         >>> r.srem('s', 'b')
 625         1
 626         >>> r.sismember('s', 'b')
 627         0
 628         >>>
 629         """
 630         self.connect()
 631         # same considerations on unicode as in set() apply here
 632         try:
 633             value = value if isinstance(value, basestring) else str(value)
 634             self._write('SREM %s %s\r\n%s\r\n' % (
 635                 name, len(value), value
 636             ))
 637         except UnicodeEncodeError, e:
 638             raise InvalidData("Error encoding unicode value for element in set '%s': %s." % (name, e))
 639         return self.get_response()
 640
 641     def sismember(self, name, value):
 642         """
 643         >>> r = Redis(db=9)
 644         >>> r.delete('s')
 645         1
 646         >>> r.sismember('s', 'b')
 647         0
 648         >>> r.sadd('s', 'a')
 649         1
 650         >>> r.sismember('s', 'b')
 651         0
 652         >>> r.sismember('s', 'a')
 653         1
 654         >>>
 655         """
 656         self.connect()
 657         # same considerations on unicode as in set() apply here
 658         try:
 659             value = value if isinstance(value, basestring) else str(value)
 660             self._write('SISMEMBER %s %s\r\n%s\r\n' % (
 661                 name, len(value), value
 662             ))
 663         except UnicodeEncodeError, e:
 664             raise InvalidData("Error encoding unicode value for element in set '%s': %s." % (name, e))
 665         return self.get_response()
 666
 667     def sinter(self, *args):
 668         """
 669         >>> r = Redis(db=9)
 670         >>> res = r.delete('s1')
 671         >>> res = r.delete('s2')
 672         >>> res = r.delete('s3')
 673         >>> r.sadd('s1', 'a')
 674         1
 675         >>> r.sadd('s2', 'a')
 676         1
 677         >>> r.sadd('s3', 'b')
 678         1
 679         >>> try:
 680         ...     r.sinter()
 681         ... except ResponseError, e:
 682         ...     print e
 683         wrong number of arguments
 684         >>> try:
 685         ...     r.sinter('l')
 686         ... except ResponseError, e:
 687         ...     print e
 688         Operation against a key holding the wrong kind of value
 689         >>> r.sinter('s1', 's2', 's3')
 690         set([])
 691         >>> r.sinter('s1', 's2')
 692         set(['a'])
 693         >>>
 694         """
 695         self.connect()
 696         self._write('SINTER %s\r\n' % ' '.join(args))
 697         return set(self.get_response())
 698
 699     def sinterstore(self, dest, *args):
 700         """
 701         >>> r = Redis(db=9)
 702         >>> res = r.delete('s1')
 703         >>> res = r.delete('s2')
 704         >>> res = r.delete('s3')
 705         >>> r.sadd('s1', 'a')
 706         1
 707         >>> r.sadd('s2', 'a')
 708         1
 709         >>> r.sadd('s3', 'b')
 710         1
 711         >>> r.sinterstore('s_s', 's1', 's2', 's3')
 712         'OK'
 713         >>> r.sinterstore('s_s', 's1', 's2')
 714         'OK'
 715         >>> r.smembers('s_s')
 716         set(['a'])
 717         >>>
 718         """
 719         self.connect()
 720         self._write('SINTERSTORE %s %s\r\n' % (dest, ' '.join(args)))
 721         return self.get_response()
 722
 723     def smembers(self, name):
 724         """
 725         >>> r = Redis(db=9)
 726         >>> r.delete('s')
 727         1
 728         >>> r.sadd('s', 'a')
 729         1
 730         >>> r.sadd('s', 'b')
 731         1
 732         >>> try:
 733         ...     r.smembers('l')
 734         ... except ResponseError, e:
 735         ...     print e
 736         Operation against a key holding the wrong kind of value
 737         >>> r.smembers('s')
 738         set(['a', 'b'])
 739         >>>
 740         """
 741         self.connect()
 742         self._write('SMEMBERS %s\r\n' % name)
 743         return set(self.get_response())
 744
 745     def select(self, db):
 746         """
 747         >>> r = Redis(db=9)
 748         >>> r.delete('a')
 749         1
 750         >>> r.select(1)
 751         'OK'
 752         >>> r.set('a', 1)
 753         'OK'
 754         >>> r.select(0)
 755         'OK'
 756         >>> r.get('a')
 757         >>>
 758         """
 759         self.connect()
 760         self._write('SELECT %s\r\n' % db)
 761         return self.get_response()
 762
 763     def move(self, name, db):
 764         """
 765         >>> r = Redis(db=9)
 766         >>> r.set('a', 'a')
 767         'OK'
 768         >>> r.select(10)
 769         'OK'
 770         >>> if r.get('a'):
 771         ...     r.delete('a')
 772         ... else:
 773         ...     print 1
 774         1
 775         >>> r.select(9)
 776         'OK'
 777         >>> r.move('a', 10)
 778         1
 779         >>> r.get('a')
 780         >>> r.select(10)
 781         'OK'
 782         >>> r.get('a')
 783         'a'
 784         >>> r.select(9)
 785         'OK'
 786         >>>
 787         """
 788         self.connect()
 789         self._write('MOVE %s %s\r\n' % (name, db))
 790         return self.get_response()
 791
 792     def save(self, background=False):
 793         """
 794         >>> r = Redis(db=9)
 795         >>> r.save()
 796         'OK'
 797         >>> try:
 798         ...     resp = r.save(background=True)
 799         ... except ResponseError, e:
 800         ...     assert str(e) == 'background save already in progress', str(e)
 801         ... else:
 802         ...     assert resp == 'OK'
 803         >>>
 804         """
 805         self.connect()
 806         if background:
 807             self._write('BGSAVE\r\n')
 808         else:
 809             self._write('SAVE\r\n')
 810         return self.get_response()
 811
 812     def lastsave(self):
 813         """
 814         >>> import time
 815         >>> r = Redis(db=9)
 816         >>> t = int(time.time())
 817         >>> r.save()
 818         'OK'
 819         >>> r.lastsave() >= t
 820         True
 821         >>>
 822         """
 823         self.connect()
 824         self._write('LASTSAVE\r\n')
 825         return self.get_response()
 826
 827     def flush(self, all_dbs=False):
 828         """
 829         >>> r = Redis(db=9)
 830         >>> r.flush()
 831         'OK'
 832         >>> # r.flush(all_dbs=True)
 833         >>>
 834         """
 835         self.connect()
 836         self._write('%s\r\n' % ('FLUSHALL' if all_dbs else 'FLUSHDB'))
 837         return self.get_response()
 838
 839     def info(self):
 840         """
 841         >>> r = Redis(db=9)
 842         >>> info = r.info()
 843         >>> info and isinstance(info, dict)
 844         True
 845         >>> isinstance(info.get('connected_clients'), int)
 846         True
 847         >>>
 848         """
 849         self.connect()
 850         self._write('INFO\r\n')
 851         info = dict()
 852         for l in self.get_response().split('\r\n'):
 853             if not l:
 854                 continue
 855             k, v = l.split(':', 1)
 856             info[k] = int(v) if v.isdigit() else v
 857         return info
 858
 859     def get_response(self):
 860         data = self._read().strip()
 861         c = data[0]
 862         if c == '-':
 863             raise ResponseError(data[5:] if data[:5] == '-ERR ' else data[1:])
 864         if c == '+':
 865             return data[1:]
 866         if c == '*':
 867             try:
 868                 num = int(data[1:])
 869             except (TypeError, ValueError):
 870                 raise InvalidResponse("Cannot convert multi-response header '%s' to integer" % data)
 871             result = list()
 872             for i in range(num):
 873                 result.append(self._get_value())
 874             return result
 875         return self._get_value(data)
 876
 877     def _get_value(self, data=None):
 878         data = data or self._read().strip()
 879         if data == '$-1':
 880             return None
 881         try:
 882             c, i = data[0], (int(data[1:]) if data.find('.') == -1 else float(data[1:]))
 883         except ValueError:
 884             raise InvalidResponse("Cannot convert data '%s' to integer" % data)
 885         if c == ':':
 886             return i
 887         if c != '$':
 888             raise InvalidResponse("Unkown response prefix for '%s'" % data)
 889         buf = []
 890         while True:
 891             data = self._read()
 892             i -= len(data)
 893             buf.append(data)
 894             if i < 0:
 895                 break
 896         return ''.join(buf)[:-2]
 897
 898     def disconnect(self):
 899         if isinstance(self._sock, socket.socket):
 900             try:
 901                 self._sock.close()
 902             except socket.error:
 903                 pass
 904         self._sock = None
 905         self._fp = None
 906
 907     def connect(self):
 908         """
 909         >>> r = Redis(db=9)
 910         >>> r.connect()
 911         >>> isinstance(r._sock, socket.socket)
 912         True
 913         >>> r.disconnect()
 914         >>>
 915         """
 916         if isinstance(self._sock, socket.socket):
 917             return
 918         try:
 919             sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
 920             sock.connect((self.host, self.port))
 921         except socket.error, e:
 922             raise ConnectionError("Error %s connecting to %s:%s. %s." % (e.args[0], self.host, self.port, e.args[1]))
 923         else:
 924             self._sock = sock
 925             self._fp = self._sock.makefile('r')
 926             if self.db:
 927                 self.select(self.db)
 928
 929
 930 if __name__ == '__main__':
 931     import doctest
 932     doctest.testmod()
 933