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subscribe to / verify headers

283
thomasv 13 years ago
parent
commit
f91dde55dd
  1. 4
      lib/interface.py
  2. 111
      lib/verifier.py

4
lib/interface.py

@ -97,6 +97,10 @@ class Interface(threading.Thread):
result = params[0]
params = []
elif method == 'blockchain.headers.subscribe':
result = params[0]
params = []
elif method == 'blockchain.address.subscribe':
addr = params[0]
result = params[1]

111
lib/verifier.py

@ -38,8 +38,14 @@ class WalletVerifier(threading.Thread):
self.targets = config.get('targets',{}) # compute targets
self.lock = threading.Lock()
#self.config.set_key('verified_tx', [], True)
#for i in range(70): self.get_target(i)
self.pending_headers = [] # headers that have not been verified
self.height = 0
self.local_height = 0
self.set_local_numblocks()
#prev_header = self.read_header(0)
#print prev_header
#sys.exit()
@ -47,10 +53,14 @@ class WalletVerifier(threading.Thread):
def run(self):
requested_merkle = []
requested_chunks = []
requested_headers = []
# subscribe to block headers
self.interface.send([ ('blockchain.headers.subscribe',[])], 'verifier')
while True:
# request missing chunks
max_index = self.wallet.blocks/2016
max_index = (self.height+1)/2016
if not requested_chunks:
for i in range(0, max_index + 1):
# test if we can read the first header of the chunk
@ -60,8 +70,14 @@ class WalletVerifier(threading.Thread):
requested_chunks.append(i)
break
# todo: request missing blocks too
# request missing headers
if not requested_chunks and self.local_height:
for i in range(self.local_height + 1, self.height + 1):
if i not in requested_headers:
print "requesting header", i
self.interface.send([ ('blockchain.block.get_header',[i])], 'verifier')
requested_headers.append(i)
# request missing tx merkle
txlist = self.wallet.get_tx_hashes()
for tx in txlist:
@ -92,8 +108,21 @@ class WalletVerifier(threading.Thread):
self.verify_chunk(index, result)
requested_chunks.remove(index)
elif method == 'blockchain.headers.subscribe':
self.height = result.get('block_height')
self.pending_headers.append(result)
elif method == 'blockchain.block.get_header':
self.verify_header(result)
height = result.get('block_height')
requested_headers.remove(height)
self.pending_headers.append(result)
# process pending headers
# todo: sort them first
for header in self.pending_headers:
self.verify_header(header)
self.pending_headers = []
def request_merkle(self, tx_hash):
@ -114,8 +143,8 @@ class WalletVerifier(threading.Thread):
def verify_chunk(self, index, hexdata):
data = hexdata.decode('hex')
height = index*2016
numblocks = len(data)/80
print "validate_chunk", index, numblocks
num = len(data)/80
print "validate_chunk", index, num
if index == 0:
previous_hash = ("0"*64)
@ -126,7 +155,7 @@ class WalletVerifier(threading.Thread):
bits, target = self.get_target(index)
for i in range(numblocks):
for i in range(num):
height = index*2016 + i
raw_header = data[i*80:(i+1)*80]
header = self.header_from_string(raw_header)
@ -141,24 +170,38 @@ class WalletVerifier(threading.Thread):
self.save_chunk(index, data)
def validate_header(self, header):
""" if there is a previous or a next block in the list, check the hash"""
def verify_header(self, header):
# add header to the blockchain file
# if there is a reorg, push it in a stack
height = header.get('block_height')
with self.lock:
self.headers[height] = header # detect conflicts
prev_header = next_header = None
if height-1 in self.headers:
prev_header = self.headers[height-1]
if height+1 in self.headers:
next_header = self.headers[height+1]
if prev_header:
prev_hash = self.hash_header(prev_header)
prev_header = self.read_header(height -1)
if not prev_header:
raise "no previous header", height
return
#prev_hash = prev_header.get('block_height')
prev_hash = self.hash_header(prev_header)
bits, target = self.get_target(height/2016)
_hash = self.hash_header(header)
try:
assert prev_hash == header.get('prev_block_hash')
assert bits == header.get('bits')
assert eval('0x'+_hash) < target
ok = True
except:
print "verify header failed", header
raise
# this could be caused by a reorg. request the previous header
ok = False
#request previous one
if ok:
self.save_header(header)
if next_header:
_hash = self.hash_header(header)
assert _hash == next_header.get('prev_block_hash')
print "verify header: ok", height
def header_to_string(self, res):
@ -194,14 +237,12 @@ class WalletVerifier(threading.Thread):
h = Hash( h + hash_decode(item[1:]) ) if is_left else Hash( hash_decode(item[1:]) + h )
return hash_encode(h)
def path(self):
wdir = user_dir()
if not os.path.exists( wdir ):
wdir = os.path.dirname(self.config.path)
return os.path.join( wdir, 'blockchain_headers')
def save_chunk(self, index, chunk):
filename = self.path()
if os.path.exists(filename):
@ -212,6 +253,24 @@ class WalletVerifier(threading.Thread):
f.seek(index*2016*80)
h = f.write(chunk)
f.close()
self.set_local_numblocks()
def save_header(self, header):
data = self.header_to_string(header).decode('hex')
assert len(data) == 80
height = header.get('block_height')
filename = self.path()
f = open(filename,'rw+')
f.seek(height*80)
h = f.write(data)
f.close()
self.set_local_numblocks()
def set_local_numblocks(self):
name = self.path()
if os.path.exists(name):
self.local_height = os.path.getsize(name)/80 - 1
# print "local height", self.local_height, os.path.getsize(name)/80.
def read_header(self, block_height):

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