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)
  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, -1])
 254         except:
 255             return None
 256
 257         vds = deserialize.BCDataStream()
 258         vds.write(raw_tx.decode('hex'))
 259
 260         return deserialize.parse_Transaction(vds, is_coinbase=False)
 261
 262     def get_history(self, addr, cache_only=False):
 263         with self.cache_lock:
 264             hist = self.history_cache.get(addr)
 265         if hist is not None:
 266             return hist
 267         if cache_only:
 268             return -1
 269
 270         with self.dblock:
 271             try:
 272                 hist = self.deserialize(self.db.Get(addr))
 273                 is_known = True
 274             except:
 275                 hist = []
 276                 is_known = False
 277
 278         # sort history, because redeeming transactions are next to the corresponding txout
 279         hist.sort(key=lambda tup: tup[2])
 280
 281         # add memory pool
 282         with self.mempool_lock:
 283             for txid in self.mempool_hist.get(addr, []):
 284                 hist.append((txid, 0, 0))
 285
 286         # uniqueness
 287         hist = set(map(lambda x: (x[0], x[2]), hist))
 288
 289         # convert to dict
 290         hist = map(lambda x: {'tx_hash': x[0], 'height': x[1]}, hist)
 291
 292         # add something to distinguish between unused and empty addresses
 293         if hist == [] and is_known:
 294             hist = ['*']
 295
 296         with self.cache_lock:
 297             self.history_cache[addr] = hist
 298         return hist
 299
 300     def get_status(self, addr, cache_only=False):
 301         tx_points = self.get_history(addr, cache_only)
 302         if cache_only and tx_points == -1:
 303             return -1
 304
 305         if not tx_points:
 306             return None
 307         if tx_points == ['*']:
 308             return '*'
 309         status = ''
 310         for tx in tx_points:
 311             status += tx.get('tx_hash') + ':%d:' % tx.get('height')
 312         return hashlib.sha256(status).digest().encode('hex')
 313
 314     def get_merkle(self, tx_hash, height):
 315
 316         block_hash = self.bitcoind('getblockhash', [height])
 317         b = self.bitcoind('getblock', [block_hash])
 318         tx_list = b.get('tx')
 319         tx_pos = tx_list.index(tx_hash)
 320
 321         merkle = map(hash_decode, tx_list)
 322         target_hash = hash_decode(tx_hash)
 323         s = []
 324         while len(merkle) != 1:
 325             if len(merkle) % 2:
 326                 merkle.append(merkle[-1])
 327             n = []
 328             while merkle:
 329                 new_hash = Hash(merkle[0] + merkle[1])
 330                 if merkle[0] == target_hash:
 331                     s.append(hash_encode(merkle[1]))
 332                     target_hash = new_hash
 333                 elif merkle[1] == target_hash:
 334                     s.append(hash_encode(merkle[0]))
 335                     target_hash = new_hash
 336                 n.append(new_hash)
 337                 merkle = merkle[2:]
 338             merkle = n
 339
 340         return {"block_height": height, "merkle": s, "pos": tx_pos}
 341
 342
 343     def add_to_history(self, addr, tx_hash, tx_pos, tx_height):
 344         # keep it sorted
 345         s = self.serialize_item(tx_hash, tx_pos, tx_height) + 40*chr(0)
 346         assert len(s) == 80
 347
 348         serialized_hist = self.batch_list[addr]
 349
 350         l = len(serialized_hist)/80
 351         for i in range(l-1, -1, -1):
 352             item = serialized_hist[80*i:80*(i+1)]
 353             item_height = int(rev_hex(item[36:39].encode('hex')), 16)
 354             if item_height <= tx_height:
 355                 serialized_hist = serialized_hist[0:80*(i+1)] + s + serialized_hist[80*(i+1):]
 356                 break
 357         else:
 358             serialized_hist = s + serialized_hist
 359
 360         self.batch_list[addr] = serialized_hist
 361
 362         # backlink
 363         txo = (tx_hash + int_to_hex(tx_pos, 4)).decode('hex')
 364         self.batch_txio[txo] = addr
 365
 366
 367
 368     def revert_add_to_history(self, addr, tx_hash, tx_pos, tx_height):
 369
 370         serialized_hist = self.batch_list[addr]
 371         s = self.serialize_item(tx_hash, tx_pos, tx_height) + 40*chr(0)
 372         if serialized_hist.find(s) == -1: raise
 373         serialized_hist = serialized_hist.replace(s, '')
 374         self.batch_list[addr] = serialized_hist
 375
 376
 377
 378     def prune_history(self, addr, undo):
 379         # remove items that have bit set to one
 380         if undo.get(addr) is None: undo[addr] = []
 381
 382         serialized_hist = self.batch_list[addr]
 383         l = len(serialized_hist)/80
 384         for i in range(l):
 385             if len(serialized_hist)/80 < self.pruning_limit: break
 386             item = serialized_hist[80*i:80*(i+1)]
 387             if item[39:40] == chr(1):
 388                 assert item[79:80] == chr(2)
 389                 serialized_hist = serialized_hist[0:80*i] + serialized_hist[80*(i+1):]
 390                 undo[addr].append(item)  # items are ordered
 391         self.batch_list[addr] = serialized_hist
 392
 393
 394     def revert_prune_history(self, addr, undo):
 395         # restore removed items
 396         serialized_hist = self.batch_list[addr]
 397
 398         if undo.get(addr) is not None:
 399             itemlist = undo.pop(addr)
 400         else:
 401             return
 402
 403         if not itemlist: return
 404
 405         l = len(serialized_hist)/80
 406         tx_item = ''
 407         for i in range(l-1, -1, -1):
 408             if tx_item == '':
 409                 if not itemlist:
 410                     break
 411                 else:
 412                     tx_item = itemlist.pop(-1) # get the last element
 413                     tx_height = int(rev_hex(tx_item[36:39].encode('hex')), 16)
 414
 415             item = serialized_hist[80*i:80*(i+1)]
 416             item_height = int(rev_hex(item[36:39].encode('hex')), 16)
 417
 418             if item_height < tx_height:
 419                 serialized_hist = serialized_hist[0:80*(i+1)] + tx_item + serialized_hist[80*(i+1):]
 420                 tx_item = ''
 421
 422         else:
 423             serialized_hist = ''.join(itemlist) + tx_item + serialized_hist
 424
 425         self.batch_list[addr] = serialized_hist
 426
 427
 428     def set_spent_bit(self, addr, txi, is_spent, txid=None, index=None, height=None):
 429         serialized_hist = self.batch_list[addr]
 430         l = len(serialized_hist)/80
 431         for i in range(l):
 432             item = serialized_hist[80*i:80*(i+1)]
 433             if item[0:36] == txi:
 434                 if is_spent:
 435                     new_item = item[0:39] + chr(1) + self.serialize_item(txid, index, height, chr(2))
 436                 else:
 437                     new_item = item[0:39] + chr(0) + chr(0)*40
 438                 serialized_hist = serialized_hist[0:80*i] + new_item + serialized_hist[80*(i+1):]
 439                 break
 440         else:
 441             self.shared.stop()
 442             hist = self.deserialize(serialized_hist)
 443             raise BaseException("prevout not found", addr, hist, txi.encode('hex'))
 444
 445         self.batch_list[addr] = serialized_hist
 446
 447
 448     def unset_spent_bit(self, addr, txi):
 449         self.set_spent_bit(addr, txi, False)
 450         self.batch_txio[txi] = addr
 451
 452
 453     def deserialize_block(self, block):
 454         txlist = block.get('tx')
 455         tx_hashes = []  # ordered txids
 456         txdict = {}     # deserialized tx
 457         is_coinbase = True
 458         for raw_tx in txlist:
 459             tx_hash = hash_encode(Hash(raw_tx.decode('hex')))
 460             tx_hashes.append(tx_hash)
 461             vds = deserialize.BCDataStream()
 462             vds.write(raw_tx.decode('hex'))
 463             tx = deserialize.parse_Transaction(vds, is_coinbase)
 464             txdict[tx_hash] = tx
 465             is_coinbase = False
 466         return tx_hashes, txdict
 467
 468     def get_undo_info(self, height):
 469         s = self.db.Get("undo%d" % (height % 100))
 470         return eval(s)
 471
 472     def write_undo_info(self, batch, height, undo_info):
 473         if self.is_test or height > self.bitcoind_height - 100:
 474             batch.Put("undo%d" % (height % 100), repr(undo_info))
 475
 476     def import_block(self, block, block_hash, block_height, sync, revert=False):
 477
 478         self.batch_list = {}  # address -> history
 479         self.batch_txio = {}  # transaction i/o -> address
 480
 481         block_inputs = []
 482         block_outputs = []
 483         addr_to_read = []
 484
 485         # deserialize transactions
 486         t0 = time.time()
 487         tx_hashes, txdict = self.deserialize_block(block)
 488
 489         t00 = time.time()
 490
 491         # undo info
 492         if revert:
 493             undo_info = self.get_undo_info(block_height)
 494         else:
 495             undo_info = {}
 496
 497
 498         if not revert:
 499             # read addresses of tx inputs
 500             for tx in txdict.values():
 501                 for x in tx.get('inputs'):
 502                     txi = (x.get('prevout_hash') + int_to_hex(x.get('prevout_n'), 4)).decode('hex')
 503                     block_inputs.append(txi)
 504
 505             block_inputs.sort()
 506             for txi in block_inputs:
 507                 try:
 508                     addr = self.db.Get(txi)
 509                 except KeyError:
 510                     # the input could come from the same block
 511                     continue
 512                 except:
 513                     traceback.print_exc(file=sys.stdout)
 514                     self.shared.stop()
 515                     raise
 516
 517                 self.batch_txio[txi] = addr
 518                 addr_to_read.append(addr)
 519
 520         else:
 521             for txid, tx in txdict.items():
 522                 for x in tx.get('outputs'):
 523                     txo = (txid + int_to_hex(x.get('index'), 4)).decode('hex')
 524                     block_outputs.append(txo)
 525                     addr_to_read.append( x.get('address') )
 526
 527                 undo = undo_info.get(txid)
 528                 for i, x in enumerate(tx.get('inputs')):
 529                     addr = undo['prev_addr'][i]
 530                     addr_to_read.append(addr)
 531
 532
 533
 534
 535
 536         # read histories of addresses
 537         for txid, tx in txdict.items():
 538             for x in tx.get('outputs'):
 539                 addr_to_read.append(x.get('address'))
 540
 541         addr_to_read.sort()
 542         for addr in addr_to_read:
 543             try:
 544                 self.batch_list[addr] = self.db.Get(addr)
 545             except KeyError:
 546                 self.batch_list[addr] = ''
 547             except:
 548                 traceback.print_exc(file=sys.stdout)
 549                 self.shared.stop()
 550                 raise
 551
 552
 553         # process
 554         t1 = time.time()
 555
 556         if revert:
 557             tx_hashes = tx_hashes[::-1]
 558
 559
 560         for txid in tx_hashes:  # must be ordered
 561             tx = txdict[txid]
 562             if not revert:
 563
 564                 undo = { 'prev_addr':[] } # contains the list of pruned items for each address in the tx; also, 'prev_addr' is a list of prev addresses
 565
 566                 prev_addr = []
 567                 for i, x in enumerate(tx.get('inputs')):
 568                     txi = (x.get('prevout_hash') + int_to_hex(x.get('prevout_n'), 4)).decode('hex')
 569                     addr = self.batch_txio[txi]
 570
 571                     # add redeem item to the history.
 572                     # add it right next to the input txi? this will break history sorting, but it's ok if I neglect tx inputs during search
 573                     self.set_spent_bit(addr, txi, True, txid, i, block_height)
 574
 575                     # when I prune, prune a pair
 576                     self.prune_history(addr, undo)
 577                     prev_addr.append(addr)
 578
 579                 undo['prev_addr'] = prev_addr
 580
 581                 # here I add only the outputs to history; maybe I want to add inputs too (that's in the other loop)
 582                 for x in tx.get('outputs'):
 583                     addr = x.get('address')
 584                     self.add_to_history(addr, txid, x.get('index'), block_height)
 585                     self.prune_history(addr, undo)  # prune here because we increased the length of the history
 586
 587                 undo_info[txid] = undo
 588
 589             else:
 590
 591                 undo = undo_info.pop(txid)
 592
 593                 for x in tx.get('outputs'):
 594                     addr = x.get('address')
 595                     self.revert_prune_history(addr, undo)
 596                     self.revert_add_to_history(addr, txid, x.get('index'), block_height)
 597
 598                 prev_addr = undo.pop('prev_addr')
 599                 for i, x in enumerate(tx.get('inputs')):
 600                     addr = prev_addr[i]
 601                     self.revert_prune_history(addr, undo)
 602                     txi = (x.get('prevout_hash') + int_to_hex(x.get('prevout_n'), 4)).decode('hex')
 603                     self.unset_spent_bit(addr, txi)
 604
 605                 assert undo == {}
 606
 607         if revert:
 608             assert undo_info == {}
 609
 610
 611         # write
 612         max_len = 0
 613         max_addr = ''
 614         t2 = time.time()
 615
 616         batch = leveldb.WriteBatch()
 617         for addr, serialized_hist in self.batch_list.items():
 618             batch.Put(addr, serialized_hist)
 619             l = len(serialized_hist)/80
 620             if l > max_len:
 621                 max_len = l
 622                 max_addr = addr
 623
 624         if not revert:
 625             # add new created outputs
 626             for txio, addr in self.batch_txio.items():
 627                 batch.Put(txio, addr)
 628             # delete spent inputs
 629             for txi in block_inputs:
 630                 batch.Delete(txi)
 631             # add undo info
 632             self.write_undo_info(batch, block_height, undo_info)
 633         else:
 634             # restore spent inputs
 635             for txio, addr in self.batch_txio.items():
 636                 # print "restoring spent input", repr(txio)
 637                 batch.Put(txio, addr)
 638             # delete spent outputs
 639             for txo in block_outputs:
 640                 batch.Delete(txo)
 641
 642         # add the max
 643         batch.Put('height', self.serialize([(block_hash, block_height, self.db_version)]))
 644
 645         # actual write
 646         self.db.Write(batch, sync=sync)
 647
 648         t3 = time.time()
 649         if t3 - t0 > 10 and not sync:
 650             print_log("block", block_height,
 651                       "parse:%0.2f " % (t00 - t0),
 652                       "read:%0.2f " % (t1 - t00),
 653                       "proc:%.2f " % (t2-t1),
 654                       "write:%.2f " % (t3-t2),
 655                       "max:", max_len, max_addr)
 656
 657         for addr in self.batch_list.keys():
 658             self.invalidate_cache(addr)
 659
 660     def add_request(self, request):
 661         # see if we can get if from cache. if not, add to queue
 662         if self.process(request, cache_only=True) == -1:
 663             self.queue.put(request)
 664
 665     def process(self, request, cache_only=False):
 666         #print "abe process", request
 667
 668         message_id = request['id']
 669         method = request['method']
 670         params = request.get('params', [])
 671         result = None
 672         error = None
 673
 674         if method == 'blockchain.numblocks.subscribe':
 675             result = self.height
 676
 677         elif method == 'blockchain.headers.subscribe':
 678             result = self.header
 679
 680         elif method == 'blockchain.address.subscribe':
 681             try:
 682                 address = params[0]
 683                 result = self.get_status(address, cache_only)
 684                 self.watch_address(address)
 685             except BaseException, e:
 686                 error = str(e) + ': ' + address
 687                 print_log("error:", error)
 688
 689         elif method == 'blockchain.address.unsubscribe':
 690             try:
 691                 password = params[0]
 692                 address = params[1]
 693                 if password == self.config.get('server', 'password'):
 694                     self.watched_addresses.remove(address)
 695                     # print_log('unsubscribed', address)
 696                     result = "ok"
 697                 else:
 698                     print_log('incorrect password')
 699                     result = "authentication error"
 700             except BaseException, e:
 701                 error = str(e) + ': ' + address
 702                 print_log("error:", error)
 703
 704         elif method == 'blockchain.address.get_history':
 705             try:
 706                 address = params[0]
 707                 result = self.get_history(address, cache_only)
 708             except BaseException, e:
 709                 error = str(e) + ': ' + address
 710                 print_log("error:", error)
 711
 712         elif method == 'blockchain.block.get_header':
 713             if cache_only:
 714                 result = -1
 715             else:
 716                 try:
 717                     height = params[0]
 718                     result = self.get_header(height)
 719                 except BaseException, e:
 720                     error = str(e) + ': %d' % height
 721                     print_log("error:", error)
 722
 723         elif method == 'blockchain.block.get_chunk':
 724             if cache_only:
 725                 result = -1
 726             else:
 727                 try:
 728                     index = params[0]
 729                     result = self.get_chunk(index)
 730                 except BaseException, e:
 731                     error = str(e) + ': %d' % index
 732                     print_log("error:", error)
 733
 734         elif method == 'blockchain.transaction.broadcast':
 735             try:
 736                 txo = self.bitcoind('sendrawtransaction', params)
 737                 print_log("sent tx:", txo)
 738                 result = txo
 739             except BaseException, e:
 740                 result = str(e)  # do not send an error
 741                 print_log("error:", result, params)
 742
 743         elif method == 'blockchain.transaction.get_merkle':
 744             if cache_only:
 745                 result = -1
 746             else:
 747                 try:
 748                     tx_hash = params[0]
 749                     tx_height = params[1]
 750                     result = self.get_merkle(tx_hash, tx_height)
 751                 except BaseException, e:
 752                     error = str(e) + ': ' + repr(params)
 753                     print_log("get_merkle error:", error)
 754
 755         elif method == 'blockchain.transaction.get':
 756             try:
 757                 tx_hash = params[0]
 758                 height = params[1]
 759                 result = self.bitcoind('getrawtransaction', [tx_hash, 0, height])
 760             except BaseException, e:
 761                 error = str(e) + ': ' + repr(params)
 762                 print_log("tx get error:", error)
 763
 764         else:
 765             error = "unknown method:%s" % method
 766
 767         if cache_only and result == -1:
 768             return -1
 769
 770         if error:
 771             self.push_response({'id': message_id, 'error': error})
 772         elif result != '':
 773             self.push_response({'id': message_id, 'result': result})
 774
 775     def watch_address(self, addr):
 776         if addr not in self.watched_addresses:
 777             self.watched_addresses.append(addr)
 778
 779     def catch_up(self, sync=True):
 780         t1 = time.time()
 781
 782         while not self.shared.stopped():
 783             # are we done yet?
 784             info = self.bitcoind('getinfo')
 785             self.bitcoind_height = info.get('blocks')
 786             bitcoind_block_hash = self.bitcoind('getblockhash', [self.bitcoind_height])
 787             if self.last_hash == bitcoind_block_hash:
 788                 self.up_to_date = True
 789                 break
 790
 791             # not done..
 792             self.up_to_date = False
 793             next_block_hash = self.bitcoind('getblockhash', [self.height + 1])
 794             next_block = self.bitcoind('getblock', [next_block_hash, 1])
 795
 796             # fixme: this is unsafe, if we revert when the undo info is not yet written
 797             revert = (random.randint(1, 100) == 1) if self.is_test else False
 798
 799             if (next_block.get('previousblockhash') == self.last_hash) and not revert:
 800
 801                 self.import_block(next_block, next_block_hash, self.height+1, sync)
 802                 self.height = self.height + 1
 803                 self.write_header(self.block2header(next_block), sync)
 804                 self.last_hash = next_block_hash
 805
 806                 if self.height % 100 == 0 and not sync:
 807                     t2 = time.time()
 808                     print_log("catch_up: block %d (%.3fs)" % (self.height, t2 - t1))
 809                     t1 = t2
 810
 811             else:
 812                 # revert current block
 813                 block = self.bitcoind('getblock', [self.last_hash, 1])
 814                 print_log("blockchain reorg", self.height, block.get('previousblockhash'), self.last_hash)
 815                 self.import_block(block, self.last_hash, self.height, sync, revert=True)
 816                 self.pop_header()
 817                 self.flush_headers()
 818
 819                 self.height -= 1
 820
 821                 # read previous header from disk
 822                 self.header = self.read_header(self.height)
 823                 self.last_hash = self.hash_header(self.header)
 824
 825         self.header = self.block2header(self.bitcoind('getblock', [self.last_hash]))
 826
 827     def memorypool_update(self):
 828         mempool_hashes = self.bitcoind('getrawmempool')
 829
 830         touched_addresses = []
 831         for tx_hash in mempool_hashes:
 832             if tx_hash in self.mempool_hashes:
 833                 continue
 834
 835             tx = self.get_mempool_transaction(tx_hash)
 836             if not tx:
 837                 continue
 838
 839             mpa = self.mempool_addresses.get(tx_hash, [])
 840             for x in tx.get('inputs'):
 841                 # we assume that the input address can be parsed by deserialize(); this is true for Electrum transactions
 842                 addr = x.get('address')
 843                 if addr and addr not in mpa:
 844                     mpa.append(addr)
 845                     touched_addresses.append(addr)
 846
 847             for x in tx.get('outputs'):
 848                 addr = x.get('address')
 849                 if addr and addr not in mpa:
 850                     mpa.append(addr)
 851                     touched_addresses.append(addr)
 852
 853             self.mempool_addresses[tx_hash] = mpa
 854             self.mempool_hashes.append(tx_hash)
 855
 856         # remove older entries from mempool_hashes
 857         self.mempool_hashes = mempool_hashes
 858
 859         # remove deprecated entries from mempool_addresses
 860         for tx_hash, addresses in self.mempool_addresses.items():
 861             if tx_hash not in self.mempool_hashes:
 862                 self.mempool_addresses.pop(tx_hash)
 863                 for addr in addresses:
 864                     touched_addresses.append(addr)
 865
 866         # rebuild mempool histories
 867         new_mempool_hist = {}
 868         for tx_hash, addresses in self.mempool_addresses.items():
 869             for addr in addresses:
 870                 h = new_mempool_hist.get(addr, [])
 871                 if tx_hash not in h:
 872                     h.append(tx_hash)
 873                 new_mempool_hist[addr] = h
 874
 875         with self.mempool_lock:
 876             self.mempool_hist = new_mempool_hist
 877
 878         # invalidate cache for touched addresses
 879         for addr in touched_addresses:
 880             self.invalidate_cache(addr)
 881
 882
 883     def invalidate_cache(self, address):
 884         with self.cache_lock:
 885             if address in self.history_cache:
 886                 print_log("cache: invalidating", address)
 887                 self.history_cache.pop(address)
 888
 889         if address in self.watched_addresses:
 890             # TODO: update cache here. if new value equals cached value, do not send notification
 891             self.address_queue.put(address)
 892
 893     def main_iteration(self):
 894         if self.shared.stopped():
 895             print_log("blockchain processor terminating")
 896             return
 897
 898         with self.dblock:
 899             t1 = time.time()
 900             self.catch_up()
 901             t2 = time.time()
 902
 903         self.memorypool_update()
 904
 905         if self.sent_height != self.height:
 906             self.sent_height = self.height
 907             self.push_response({
 908                 'id': None,
 909                 'method': 'blockchain.numblocks.subscribe',
 910                 'params': [self.height],
 911             })
 912
 913         if self.sent_header != self.header:
 914             print_log("blockchain: %d (%.3fs)" % (self.height, t2 - t1))
 915             self.sent_header = self.header
 916             self.push_response({
 917                 'id': None,
 918                 'method': 'blockchain.headers.subscribe',
 919                 'params': [self.header],
 920             })
 921
 922         while True:
 923             try:
 924                 addr = self.address_queue.get(False)
 925             except:
 926                 break
 927             if addr in self.watched_addresses:
 928                 status = self.get_status(addr)
 929                 self.push_response({
 930                     'id': None,
 931                     'method': 'blockchain.address.subscribe',
 932                     'params': [addr, status],
 933                 })
 934
 935         if not self.shared.stopped():
 936             threading.Timer(10, self.main_iteration).start()
 937         else:
 938             print_log("blockchain processor terminating")