backends/bitcoind/blockchain_processor.py

   1 import ast
   2 import hashlib
   3 from json import dumps, loads
   4 import leveldb
   5 import os
   6 from Queue import Queue
   7 import random
   8 import sys
   9 import time
  10 import threading
  11 import traceback
  12 import urllib
  13
  14 from backends.bitcoind import deserialize
  15 from processor import Processor, print_log
  16 from utils import *
  17
  18
  19 class BlockchainProcessor(Processor):
  20
  21     def __init__(self, config, shared):
  22         Processor.__init__(self)
  23
  24         self.shared = shared
  25         self.config = config
  26         self.up_to_date = False
  27         self.watched_addresses = []
  28         self.history_cache = {}
  29         self.chunk_cache = {}
  30         self.cache_lock = threading.Lock()
  31         self.headers_data = ''
  32
  33         self.mempool_addresses = {}
  34         self.mempool_hist = {}
  35         self.mempool_hashes = []
  36         self.mempool_lock = threading.Lock()
  37
  38         self.address_queue = Queue()
  39         self.dbpath = config.get('leveldb', 'path')
  40         self.pruning_limit = config.getint('leveldb', 'pruning_limit')
  41         self.db_version = 1 # increase this when database needs to be updated
  42
  43         self.dblock = threading.Lock()
  44         try:
  45             self.db = leveldb.LevelDB(self.dbpath, paranoid_checks=True)
  46         except:
  47             traceback.print_exc(file=sys.stdout)
  48             self.shared.stop()
  49
  50         self.bitcoind_url = 'http://%s:%s@%s:%s/' % (
  51             config.get('bitcoind', 'user'),
  52             config.get('bitcoind', 'password'),
  53             config.get('bitcoind', 'host'),
  54             config.get('bitcoind', 'port'))
  55
  56         while True:
  57             try:
  58                 self.bitcoind('getinfo')
  59                 break
  60             except:
  61                 print_log('cannot contact bitcoind...')
  62                 time.sleep(5)
  63                 continue
  64
  65         self.height = 0
  66         self.is_test = False
  67         self.sent_height = 0
  68         self.sent_header = None
  69
  70         try:
  71             hist = self.deserialize(self.db.Get('height'))
  72             self.last_hash, self.height, db_version = hist[0]
  73             print_log("Database version", self.db_version)
  74             print_log("Blockchain height", self.height)
  75         except:
  76             traceback.print_exc(file=sys.stdout)
  77             print_log('initializing database')
  78             self.height = 0
  79             self.last_hash = '000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f'
  80             db_version = self.db_version
  81
  82         # check version
  83         if self.db_version != db_version:
  84             print_log("Your database '%s' is deprecated. Please create a new database"%self.dbpath)
  85             self.shared.stop()
  86             return
  87
  88         # catch_up headers
  89         self.init_headers(self.height)
  90
  91         threading.Timer(0, lambda: self.catch_up(sync=False)).start()
  92         while not shared.stopped() and not self.up_to_date:
  93             try:
  94                 time.sleep(1)
  95             except:
  96                 print "keyboard interrupt: stopping threads"
  97                 shared.stop()
  98                 sys.exit(0)
  99
 100         print_log("Blockchain is up to date.")
 101         self.memorypool_update()
 102         print_log("Memory pool initialized.")
 103
 104         threading.Timer(10, self.main_iteration).start()
 105
 106     def bitcoind(self, method, params=[]):
 107         postdata = dumps({"method": method, 'params': params, 'id': 'jsonrpc'})
 108         try:
 109             respdata = urllib.urlopen(self.bitcoind_url, postdata).read()
 110         except:
 111             traceback.print_exc(file=sys.stdout)
 112             self.shared.stop()
 113
 114         r = loads(respdata)
 115         if r['error'] is not None:
 116             raise BaseException(r['error'])
 117         return r.get('result')
 118
 119     def serialize(self, h):
 120         s = ''
 121         for txid, txpos, height in h:
 122             s += self.serialize_item(txid, txpos, height)
 123         return s
 124
 125     def serialize_item(self, txid, txpos, height, spent=chr(0)):
 126         s = (txid + int_to_hex(txpos, 4) + int_to_hex(height, 3)).decode('hex') + spent
 127         return s
 128
 129     def deserialize_item(self,s):
 130         txid = s[0:32].encode('hex')
 131         txpos = int(rev_hex(s[32:36].encode('hex')), 16)
 132         height = int(rev_hex(s[36:39].encode('hex')), 16)
 133         spent = s[39:40]
 134         return (txid, txpos, height, spent)
 135
 136     def deserialize(self, s):
 137         h = []
 138         while s:
 139             txid, txpos, height, spent = self.deserialize_item(s[0:40])
 140             h.append((txid, txpos, height))
 141             if spent == chr(1):
 142                 txid, txpos, height, spent = self.deserialize_item(s[40:80])
 143                 h.append((txid, txpos, height))
 144             s = s[80:]
 145         return h
 146
 147     def block2header(self, b):
 148         return {
 149             "block_height": b.get('height'),
 150             "version": b.get('version'),
 151             "prev_block_hash": b.get('previousblockhash'),
 152             "merkle_root": b.get('merkleroot'),
 153             "timestamp": b.get('time'),
 154             "bits": int(b.get('bits'), 16),
 155             "nonce": b.get('nonce'),
 156         }
 157
 158     def get_header(self, height):
 159         block_hash = self.bitcoind('getblockhash', [height])
 160         b = self.bitcoind('getblock', [block_hash])
 161         return self.block2header(b)
 162
 163     def init_headers(self, db_height):
 164         self.chunk_cache = {}
 165         self.headers_filename = os.path.join(self.dbpath, 'blockchain_headers')
 166
 167         if os.path.exists(self.headers_filename):
 168             height = os.path.getsize(self.headers_filename)/80 - 1   # the current height
 169             if height > 0:
 170                 prev_hash = self.hash_header(self.read_header(height))
 171             else:
 172                 prev_hash = None
 173         else:
 174             open(self.headers_filename, 'wb').close()
 175             prev_hash = None
 176             height = -1
 177
 178         if height < db_height:
 179             print_log("catching up missing headers:", height, db_height)
 180
 181         try:
 182             while height < db_height:
 183                 height = height + 1
 184                 header = self.get_header(height)
 185                 if height > 1:
 186                     assert prev_hash == header.get('prev_block_hash')
 187                 self.write_header(header, sync=False)
 188                 prev_hash = self.hash_header(header)
 189                 if (height % 1000) == 0:
 190                     print_log("headers file:", height)
 191         except KeyboardInterrupt:
 192             self.flush_headers()
 193             sys.exit()
 194
 195         self.flush_headers()
 196
 197     def hash_header(self, header):
 198         return rev_hex(Hash(header_to_string(header).decode('hex')).encode('hex'))
 199
 200     def read_header(self, block_height):
 201         if os.path.exists(self.headers_filename):
 202             with open(self.headers_filename, 'rb') as f:
 203                 f.seek(block_height * 80)
 204                 h = f.read(80)
 205             if len(h) == 80:
 206                 h = header_from_string(h)
 207                 return h
 208
 209     def read_chunk(self, index):
 210         with open(self.headers_filename, 'rb') as f:
 211             f.seek(index*2016*80)
 212             chunk = f.read(2016*80)
 213         return chunk.encode('hex')
 214
 215     def write_header(self, header, sync=True):
 216         if not self.headers_data:
 217             self.headers_offset = header.get('block_height')
 218
 219         self.headers_data += header_to_string(header).decode('hex')
 220         if sync or len(self.headers_data) > 40*100:
 221             self.flush_headers()
 222
 223         with self.cache_lock:
 224             chunk_index = header.get('block_height')/2016
 225             if self.chunk_cache.get(chunk_index):
 226                 self.chunk_cache.pop(chunk_index)
 227
 228     def pop_header(self):
 229         # we need to do this only if we have not flushed
 230         if self.headers_data:
 231             self.headers_data = self.headers_data[:-40]
 232
 233     def flush_headers(self):
 234         if not self.headers_data:
 235             return
 236         with open(self.headers_filename, 'rb+') as f:
 237             f.seek(self.headers_offset*80)
 238             f.write(self.headers_data)
 239         self.headers_data = ''
 240
 241     def get_chunk(self, i):
 242         # store them on disk; store the current chunk in memory
 243         with self.cache_lock:
 244             chunk = self.chunk_cache.get(i)
 245             if not chunk:
 246                 chunk = self.read_chunk(i)
 247                 self.chunk_cache[i] = chunk
 248
 249         return chunk
 250
 251     def get_mempool_transaction(self, txid):
 252         try:
 253             raw_tx = self.bitcoind('getrawtransaction', [txid, 0])
 254         except:
 255             return None
 256
 257         vds = deserialize.BCDataStream()
 258         vds.write(raw_tx.decode('hex'))
 259         try:
 260             return deserialize.parse_Transaction(vds, is_coinbase=False)
 261         except:
 262             print_log("ERROR: cannot parse", txid)
 263             return None
 264
 265     def get_history(self, addr, cache_only=False):
 266         with self.cache_lock:
 267             hist = self.history_cache.get(addr)
 268         if hist is not None:
 269             return hist
 270         if cache_only:
 271             return -1
 272
 273         with self.dblock:
 274             try:
 275                 hist = self.deserialize(self.db.Get(addr))
 276                 is_known = True
 277             except:
 278                 hist = []
 279                 is_known = False
 280
 281         # sort history, because redeeming transactions are next to the corresponding txout
 282         hist.sort(key=lambda tup: tup[2])
 283
 284         # add memory pool
 285         with self.mempool_lock:
 286             for txid in self.mempool_hist.get(addr, []):
 287                 hist.append((txid, 0, 0))
 288
 289         # uniqueness
 290         hist = set(map(lambda x: (x[0], x[2]), hist))
 291
 292         # convert to dict
 293         hist = map(lambda x: {'tx_hash': x[0], 'height': x[1]}, hist)
 294
 295         # add something to distinguish between unused and empty addresses
 296         if hist == [] and is_known:
 297             hist = ['*']
 298
 299         with self.cache_lock:
 300             self.history_cache[addr] = hist
 301         return hist
 302
 303     def get_status(self, addr, cache_only=False):
 304         tx_points = self.get_history(addr, cache_only)
 305         if cache_only and tx_points == -1:
 306             return -1
 307
 308         if not tx_points:
 309             return None
 310         if tx_points == ['*']:
 311             return '*'
 312         status = ''
 313         for tx in tx_points:
 314             status += tx.get('tx_hash') + ':%d:' % tx.get('height')
 315         return hashlib.sha256(status).digest().encode('hex')
 316
 317     def get_merkle(self, tx_hash, height):
 318
 319         block_hash = self.bitcoind('getblockhash', [height])
 320         b = self.bitcoind('getblock', [block_hash])
 321         tx_list = b.get('tx')
 322         tx_pos = tx_list.index(tx_hash)
 323
 324         merkle = map(hash_decode, tx_list)
 325         target_hash = hash_decode(tx_hash)
 326         s = []
 327         while len(merkle) != 1:
 328             if len(merkle) % 2:
 329                 merkle.append(merkle[-1])
 330             n = []
 331             while merkle:
 332                 new_hash = Hash(merkle[0] + merkle[1])
 333                 if merkle[0] == target_hash:
 334                     s.append(hash_encode(merkle[1]))
 335                     target_hash = new_hash
 336                 elif merkle[1] == target_hash:
 337                     s.append(hash_encode(merkle[0]))
 338                     target_hash = new_hash
 339                 n.append(new_hash)
 340                 merkle = merkle[2:]
 341             merkle = n
 342
 343         return {"block_height": height, "merkle": s, "pos": tx_pos}
 344
 345
 346     def add_to_history(self, addr, tx_hash, tx_pos, tx_height):
 347         # keep it sorted
 348         s = self.serialize_item(tx_hash, tx_pos, tx_height) + 40*chr(0)
 349         assert len(s) == 80
 350
 351         serialized_hist = self.batch_list[addr]
 352
 353         l = len(serialized_hist)/80
 354         for i in range(l-1, -1, -1):
 355             item = serialized_hist[80*i:80*(i+1)]
 356             item_height = int(rev_hex(item[36:39].encode('hex')), 16)
 357             if item_height <= tx_height:
 358                 serialized_hist = serialized_hist[0:80*(i+1)] + s + serialized_hist[80*(i+1):]
 359                 break
 360         else:
 361             serialized_hist = s + serialized_hist
 362
 363         self.batch_list[addr] = serialized_hist
 364
 365         # backlink
 366         txo = (tx_hash + int_to_hex(tx_pos, 4)).decode('hex')
 367         self.batch_txio[txo] = addr
 368
 369
 370
 371     def revert_add_to_history(self, addr, tx_hash, tx_pos, tx_height):
 372
 373         serialized_hist = self.batch_list[addr]
 374         s = self.serialize_item(tx_hash, tx_pos, tx_height) + 40*chr(0)
 375         if serialized_hist.find(s) == -1: raise
 376         serialized_hist = serialized_hist.replace(s, '')
 377         self.batch_list[addr] = serialized_hist
 378
 379
 380
 381     def prune_history(self, addr, undo):
 382         # remove items that have bit set to one
 383         if undo.get(addr) is None: undo[addr] = []
 384
 385         serialized_hist = self.batch_list[addr]
 386         l = len(serialized_hist)/80
 387         for i in range(l):
 388             if len(serialized_hist)/80 < self.pruning_limit: break
 389             item = serialized_hist[80*i:80*(i+1)]
 390             if item[39:40] == chr(1):
 391                 assert item[79:80] == chr(2)
 392                 serialized_hist = serialized_hist[0:80*i] + serialized_hist[80*(i+1):]
 393                 undo[addr].append(item)  # items are ordered
 394         self.batch_list[addr] = serialized_hist
 395
 396
 397     def revert_prune_history(self, addr, undo):
 398         # restore removed items
 399         serialized_hist = self.batch_list[addr]
 400
 401         if undo.get(addr) is not None:
 402             itemlist = undo.pop(addr)
 403         else:
 404             return
 405
 406         if not itemlist: return
 407
 408         l = len(serialized_hist)/80
 409         tx_item = ''
 410         for i in range(l-1, -1, -1):
 411             if tx_item == '':
 412                 if not itemlist:
 413                     break
 414                 else:
 415                     tx_item = itemlist.pop(-1) # get the last element
 416                     tx_height = int(rev_hex(tx_item[36:39].encode('hex')), 16)
 417
 418             item = serialized_hist[80*i:80*(i+1)]
 419             item_height = int(rev_hex(item[36:39].encode('hex')), 16)
 420
 421             if item_height < tx_height:
 422                 serialized_hist = serialized_hist[0:80*(i+1)] + tx_item + serialized_hist[80*(i+1):]
 423                 tx_item = ''
 424
 425         else:
 426             serialized_hist = ''.join(itemlist) + tx_item + serialized_hist
 427
 428         self.batch_list[addr] = serialized_hist
 429
 430
 431     def set_spent_bit(self, addr, txi, is_spent, txid=None, index=None, height=None):
 432         serialized_hist = self.batch_list[addr]
 433         l = len(serialized_hist)/80
 434         for i in range(l):
 435             item = serialized_hist[80*i:80*(i+1)]
 436             if item[0:36] == txi:
 437                 if is_spent:
 438                     new_item = item[0:39] + chr(1) + self.serialize_item(txid, index, height, chr(2))
 439                 else:
 440                     new_item = item[0:39] + chr(0) + chr(0)*40
 441                 serialized_hist = serialized_hist[0:80*i] + new_item + serialized_hist[80*(i+1):]
 442                 break
 443         else:
 444             self.shared.stop()
 445             hist = self.deserialize(serialized_hist)
 446             raise BaseException("prevout not found", addr, hist, txi.encode('hex'))
 447
 448         self.batch_list[addr] = serialized_hist
 449
 450
 451     def unset_spent_bit(self, addr, txi):
 452         self.set_spent_bit(addr, txi, False)
 453         self.batch_txio[txi] = addr
 454
 455
 456     def deserialize_block(self, block):
 457         txlist = block.get('tx')
 458         tx_hashes = []  # ordered txids
 459         txdict = {}     # deserialized tx
 460         is_coinbase = True
 461         for raw_tx in txlist:
 462             tx_hash = hash_encode(Hash(raw_tx.decode('hex')))
 463             vds = deserialize.BCDataStream()
 464             vds.write(raw_tx.decode('hex'))
 465             try:
 466                 tx = deserialize.parse_Transaction(vds, is_coinbase)
 467             except:
 468                 print_log("ERROR: cannot parse", tx_hash)
 469                 continue
 470             tx_hashes.append(tx_hash)
 471             txdict[tx_hash] = tx
 472             is_coinbase = False
 473         return tx_hashes, txdict
 474
 475     def get_undo_info(self, height):
 476         s = self.db.Get("undo%d" % (height % 100))
 477         return eval(s)
 478
 479     def write_undo_info(self, batch, height, undo_info):
 480         if self.is_test or height > self.bitcoind_height - 100:
 481             batch.Put("undo%d" % (height % 100), repr(undo_info))
 482
 483     def import_block(self, block, block_hash, block_height, sync, revert=False):
 484
 485         self.batch_list = {}  # address -> history
 486         self.batch_txio = {}  # transaction i/o -> address
 487
 488         block_inputs = []
 489         block_outputs = []
 490         addr_to_read = []
 491
 492         # deserialize transactions
 493         t0 = time.time()
 494         tx_hashes, txdict = self.deserialize_block(block)
 495
 496         t00 = time.time()
 497
 498         # undo info
 499         if revert:
 500             undo_info = self.get_undo_info(block_height)
 501         else:
 502             undo_info = {}
 503
 504
 505         if not revert:
 506             # read addresses of tx inputs
 507             for tx in txdict.values():
 508                 for x in tx.get('inputs'):
 509                     txi = (x.get('prevout_hash') + int_to_hex(x.get('prevout_n'), 4)).decode('hex')
 510                     block_inputs.append(txi)
 511
 512             block_inputs.sort()
 513             for txi in block_inputs:
 514                 try:
 515                     addr = self.db.Get(txi)
 516                 except KeyError:
 517                     # the input could come from the same block
 518                     continue
 519                 except:
 520                     traceback.print_exc(file=sys.stdout)
 521                     self.shared.stop()
 522                     raise
 523
 524                 self.batch_txio[txi] = addr
 525                 addr_to_read.append(addr)
 526
 527         else:
 528             for txid, tx in txdict.items():
 529                 for x in tx.get('outputs'):
 530                     txo = (txid + int_to_hex(x.get('index'), 4)).decode('hex')
 531                     block_outputs.append(txo)
 532                     addr_to_read.append( x.get('address') )
 533
 534                 undo = undo_info.get(txid)
 535                 for i, x in enumerate(tx.get('inputs')):
 536                     addr = undo['prev_addr'][i]
 537                     addr_to_read.append(addr)
 538
 539
 540
 541
 542
 543         # read histories of addresses
 544         for txid, tx in txdict.items():
 545             for x in tx.get('outputs'):
 546                 addr_to_read.append(x.get('address'))
 547
 548         addr_to_read.sort()
 549         for addr in addr_to_read:
 550             try:
 551                 self.batch_list[addr] = self.db.Get(addr)
 552             except KeyError:
 553                 self.batch_list[addr] = ''
 554             except:
 555                 traceback.print_exc(file=sys.stdout)
 556                 self.shared.stop()
 557                 raise
 558
 559
 560         # process
 561         t1 = time.time()
 562
 563         if revert:
 564             tx_hashes = tx_hashes[::-1]
 565
 566
 567         for txid in tx_hashes:  # must be ordered
 568             tx = txdict[txid]
 569             if not revert:
 570
 571                 undo = { 'prev_addr':[] } # contains the list of pruned items for each address in the tx; also, 'prev_addr' is a list of prev addresses
 572
 573                 prev_addr = []
 574                 for i, x in enumerate(tx.get('inputs')):
 575                     txi = (x.get('prevout_hash') + int_to_hex(x.get('prevout_n'), 4)).decode('hex')
 576                     addr = self.batch_txio[txi]
 577
 578                     # add redeem item to the history.
 579                     # add it right next to the input txi? this will break history sorting, but it's ok if I neglect tx inputs during search
 580                     self.set_spent_bit(addr, txi, True, txid, i, block_height)
 581
 582                     # when I prune, prune a pair
 583                     self.prune_history(addr, undo)
 584                     prev_addr.append(addr)
 585
 586                 undo['prev_addr'] = prev_addr
 587
 588                 # here I add only the outputs to history; maybe I want to add inputs too (that's in the other loop)
 589                 for x in tx.get('outputs'):
 590                     addr = x.get('address')
 591                     self.add_to_history(addr, txid, x.get('index'), block_height)
 592                     self.prune_history(addr, undo)  # prune here because we increased the length of the history
 593
 594                 undo_info[txid] = undo
 595
 596             else:
 597
 598                 undo = undo_info.pop(txid)
 599
 600                 for x in tx.get('outputs'):
 601                     addr = x.get('address')
 602                     self.revert_prune_history(addr, undo)
 603                     self.revert_add_to_history(addr, txid, x.get('index'), block_height)
 604
 605                 prev_addr = undo.pop('prev_addr')
 606                 for i, x in enumerate(tx.get('inputs')):
 607                     addr = prev_addr[i]
 608                     self.revert_prune_history(addr, undo)
 609                     txi = (x.get('prevout_hash') + int_to_hex(x.get('prevout_n'), 4)).decode('hex')
 610                     self.unset_spent_bit(addr, txi)
 611
 612                 assert undo == {}
 613
 614         if revert:
 615             assert undo_info == {}
 616
 617
 618         # write
 619         max_len = 0
 620         max_addr = ''
 621         t2 = time.time()
 622
 623         batch = leveldb.WriteBatch()
 624         for addr, serialized_hist in self.batch_list.items():
 625             batch.Put(addr, serialized_hist)
 626             l = len(serialized_hist)/80
 627             if l > max_len:
 628                 max_len = l
 629                 max_addr = addr
 630
 631         if not revert:
 632             # add new created outputs
 633             for txio, addr in self.batch_txio.items():
 634                 batch.Put(txio, addr)
 635             # delete spent inputs
 636             for txi in block_inputs:
 637                 batch.Delete(txi)
 638             # add undo info
 639             self.write_undo_info(batch, block_height, undo_info)
 640         else:
 641             # restore spent inputs
 642             for txio, addr in self.batch_txio.items():
 643                 # print "restoring spent input", repr(txio)
 644                 batch.Put(txio, addr)
 645             # delete spent outputs
 646             for txo in block_outputs:
 647                 batch.Delete(txo)
 648
 649         # add the max
 650         batch.Put('height', self.serialize([(block_hash, block_height, self.db_version)]))
 651
 652         # actual write
 653         self.db.Write(batch, sync=sync)
 654
 655         t3 = time.time()
 656         if t3 - t0 > 10 and not sync:
 657             print_log("block", block_height,
 658                       "parse:%0.2f " % (t00 - t0),
 659                       "read:%0.2f " % (t1 - t00),
 660                       "proc:%.2f " % (t2-t1),
 661                       "write:%.2f " % (t3-t2),
 662                       "max:", max_len, max_addr)
 663
 664         for addr in self.batch_list.keys():
 665             self.invalidate_cache(addr)
 666
 667     def add_request(self, request):
 668         # see if we can get if from cache. if not, add to queue
 669         if self.process(request, cache_only=True) == -1:
 670             self.queue.put(request)
 671
 672     def process(self, request, cache_only=False):
 673         #print "abe process", request
 674
 675         message_id = request['id']
 676         method = request['method']
 677         params = request.get('params', [])
 678         result = None
 679         error = None
 680
 681         if method == 'blockchain.numblocks.subscribe':
 682             result = self.height
 683
 684         elif method == 'blockchain.headers.subscribe':
 685             result = self.header
 686
 687         elif method == 'blockchain.address.subscribe':
 688             try:
 689                 address = params[0]
 690                 result = self.get_status(address, cache_only)
 691                 self.watch_address(address)
 692             except BaseException, e:
 693                 error = str(e) + ': ' + address
 694                 print_log("error:", error)
 695
 696         elif method == 'blockchain.address.unsubscribe':
 697             try:
 698                 password = params[0]
 699                 address = params[1]
 700                 if password == self.config.get('server', 'password'):
 701                     self.watched_addresses.remove(address)
 702                     # print_log('unsubscribed', address)
 703                     result = "ok"
 704                 else:
 705                     print_log('incorrect password')
 706                     result = "authentication error"
 707             except BaseException, e:
 708                 error = str(e) + ': ' + address
 709                 print_log("error:", error)
 710
 711         elif method == 'blockchain.address.get_history':
 712             try:
 713                 address = params[0]
 714                 result = self.get_history(address, cache_only)
 715             except BaseException, e:
 716                 error = str(e) + ': ' + address
 717                 print_log("error:", error)
 718
 719         elif method == 'blockchain.block.get_header':
 720             if cache_only:
 721                 result = -1
 722             else:
 723                 try:
 724                     height = params[0]
 725                     result = self.get_header(height)
 726                 except BaseException, e:
 727                     error = str(e) + ': %d' % height
 728                     print_log("error:", error)
 729
 730         elif method == 'blockchain.block.get_chunk':
 731             if cache_only:
 732                 result = -1
 733             else:
 734                 try:
 735                     index = params[0]
 736                     result = self.get_chunk(index)
 737                 except BaseException, e:
 738                     error = str(e) + ': %d' % index
 739                     print_log("error:", error)
 740
 741         elif method == 'blockchain.transaction.broadcast':
 742             try:
 743                 txo = self.bitcoind('sendrawtransaction', params)
 744                 print_log("sent tx:", txo)
 745                 result = txo
 746             except BaseException, e:
 747                 result = str(e)  # do not send an error
 748                 print_log("error:", result, params)
 749
 750         elif method == 'blockchain.transaction.get_merkle':
 751             if cache_only:
 752                 result = -1
 753             else:
 754                 try:
 755                     tx_hash = params[0]
 756                     tx_height = params[1]
 757                     result = self.get_merkle(tx_hash, tx_height)
 758                 except BaseException, e:
 759                     error = str(e) + ': ' + repr(params)
 760                     print_log("get_merkle error:", error)
 761
 762         elif method == 'blockchain.transaction.get':
 763             try:
 764                 tx_hash = params[0]
 765                 result = self.bitcoind('getrawtransaction', [tx_hash, 0])
 766             except BaseException, e:
 767                 error = str(e) + ': ' + repr(params)
 768                 print_log("tx get error:", error)
 769
 770         else:
 771             error = "unknown method:%s" % method
 772
 773         if cache_only and result == -1:
 774             return -1
 775
 776         if error:
 777             self.push_response({'id': message_id, 'error': error})
 778         elif result != '':
 779             self.push_response({'id': message_id, 'result': result})
 780
 781     def watch_address(self, addr):
 782         if addr not in self.watched_addresses:
 783             self.watched_addresses.append(addr)
 784
 785     def getfullblock(self, block_hash):
 786         block = self.bitcoind('getblock', [block_hash])
 787
 788         rawtxreq = []
 789         i = 0
 790         for txid in block['tx']:
 791             rawtxreq.append({
 792                 "method": "getrawtransaction",
 793                 "params": [txid],
 794                 "id": i,
 795             })
 796             i += 1
 797
 798         postdata = dumps(rawtxreq)
 799         try:
 800             respdata = urllib.urlopen(self.bitcoind_url, postdata).read()
 801         except:
 802             traceback.print_exc(file=sys.stdout)
 803             self.shared.stop()
 804
 805         r = loads(respdata)
 806         rawtxdata = []
 807         for ir in r:
 808             if ir['error'] is not None:
 809                 raise BaseException(ir['error'])
 810             rawtxdata.append(ir['result'])
 811         block['tx'] = rawtxdata
 812         return block
 813
 814     def catch_up(self, sync=True):
 815         t1 = time.time()
 816
 817         while not self.shared.stopped():
 818             # are we done yet?
 819             info = self.bitcoind('getinfo')
 820             self.bitcoind_height = info.get('blocks')
 821             bitcoind_block_hash = self.bitcoind('getblockhash', [self.bitcoind_height])
 822             if self.last_hash == bitcoind_block_hash:
 823                 self.up_to_date = True
 824                 break
 825
 826             # not done..
 827             self.up_to_date = False
 828             next_block_hash = self.bitcoind('getblockhash', [self.height + 1])
 829             next_block = self.getfullblock(next_block_hash)
 830
 831             # fixme: this is unsafe, if we revert when the undo info is not yet written
 832             revert = (random.randint(1, 100) == 1) if self.is_test else False
 833
 834             if (next_block.get('previousblockhash') == self.last_hash) and not revert:
 835
 836                 self.import_block(next_block, next_block_hash, self.height+1, sync)
 837                 self.height = self.height + 1
 838                 self.write_header(self.block2header(next_block), sync)
 839                 self.last_hash = next_block_hash
 840
 841                 if self.height % 100 == 0 and not sync:
 842                     t2 = time.time()
 843                     print_log("catch_up: block %d (%.3fs)" % (self.height, t2 - t1))
 844                     t1 = t2
 845
 846             else:
 847                 # revert current block
 848                 block = self.getfullblock(self.last_hash)
 849                 print_log("blockchain reorg", self.height, block.get('previousblockhash'), self.last_hash)
 850                 self.import_block(block, self.last_hash, self.height, sync, revert=True)
 851                 self.pop_header()
 852                 self.flush_headers()
 853
 854                 self.height -= 1
 855
 856                 # read previous header from disk
 857                 self.header = self.read_header(self.height)
 858                 self.last_hash = self.hash_header(self.header)
 859
 860         self.header = self.block2header(self.bitcoind('getblock', [self.last_hash]))
 861
 862     def memorypool_update(self):
 863         mempool_hashes = self.bitcoind('getrawmempool')
 864
 865         touched_addresses = []
 866         for tx_hash in mempool_hashes:
 867             if tx_hash in self.mempool_hashes:
 868                 continue
 869
 870             tx = self.get_mempool_transaction(tx_hash)
 871             if not tx:
 872                 continue
 873
 874             mpa = self.mempool_addresses.get(tx_hash, [])
 875             for x in tx.get('inputs'):
 876                 # we assume that the input address can be parsed by deserialize(); this is true for Electrum transactions
 877                 addr = x.get('address')
 878                 if addr and addr not in mpa:
 879                     mpa.append(addr)
 880                     touched_addresses.append(addr)
 881
 882             for x in tx.get('outputs'):
 883                 addr = x.get('address')
 884                 if addr and addr not in mpa:
 885                     mpa.append(addr)
 886                     touched_addresses.append(addr)
 887
 888             self.mempool_addresses[tx_hash] = mpa
 889             self.mempool_hashes.append(tx_hash)
 890
 891         # remove older entries from mempool_hashes
 892         self.mempool_hashes = mempool_hashes
 893
 894         # remove deprecated entries from mempool_addresses
 895         for tx_hash, addresses in self.mempool_addresses.items():
 896             if tx_hash not in self.mempool_hashes:
 897                 self.mempool_addresses.pop(tx_hash)
 898                 for addr in addresses:
 899                     touched_addresses.append(addr)
 900
 901         # rebuild mempool histories
 902         new_mempool_hist = {}
 903         for tx_hash, addresses in self.mempool_addresses.items():
 904             for addr in addresses:
 905                 h = new_mempool_hist.get(addr, [])
 906                 if tx_hash not in h:
 907                     h.append(tx_hash)
 908                 new_mempool_hist[addr] = h
 909
 910         with self.mempool_lock:
 911             self.mempool_hist = new_mempool_hist
 912
 913         # invalidate cache for touched addresses
 914         for addr in touched_addresses:
 915             self.invalidate_cache(addr)
 916
 917
 918     def invalidate_cache(self, address):
 919         with self.cache_lock:
 920             if address in self.history_cache:
 921                 print_log("cache: invalidating", address)
 922                 self.history_cache.pop(address)
 923
 924         if address in self.watched_addresses:
 925             # TODO: update cache here. if new value equals cached value, do not send notification
 926             self.address_queue.put(address)
 927
 928     def main_iteration(self):
 929         if self.shared.stopped():
 930             print_log("blockchain processor terminating")
 931             return
 932
 933         with self.dblock:
 934             t1 = time.time()
 935             self.catch_up()
 936             t2 = time.time()
 937
 938         self.memorypool_update()
 939
 940         if self.sent_height != self.height:
 941             self.sent_height = self.height
 942             self.push_response({
 943                 'id': None,
 944                 'method': 'blockchain.numblocks.subscribe',
 945                 'params': [self.height],
 946             })
 947
 948         if self.sent_header != self.header:
 949             print_log("blockchain: %d (%.3fs)" % (self.height, t2 - t1))
 950             self.sent_header = self.header
 951             self.push_response({
 952                 'id': None,
 953                 'method': 'blockchain.headers.subscribe',
 954                 'params': [self.header],
 955             })
 956
 957         while True:
 958             try:
 959                 addr = self.address_queue.get(False)
 960             except:
 961                 break
 962             if addr in self.watched_addresses:
 963                 status = self.get_status(addr)
 964                 self.push_response({
 965                     'id': None,
 966                     'method': 'blockchain.address.subscribe',
 967                     'params': [addr, status],
 968                 })
 969
 970         if not self.shared.stopped():
 971             threading.Timer(10, self.main_iteration).start()
 972         else:
 973             print_log("blockchain processor terminating")