class Blockchain(threading.Thread):
- def __init__(self, config):
+ def __init__(self, config, network):
threading.Thread.__init__(self)
self.daemon = True
self.config = config
+ self.network = network
self.lock = threading.Lock()
- self.height = 0
self.local_height = 0
self.running = False
self.headers_url = 'http://headers.electrum.org/blockchain_headers'
self.queue = Queue.Queue()
+ def height(self):
+ return self.local_height
+
+
def stop(self):
with self.lock: self.running = False
if not result: continue
- i, result = result
- header= result.get('result')
+ i, header = result
+ if not header: continue
+
height = header.get('block_height')
+ if height <= self.local_height:
+ continue
+
if height > self.local_height + 50:
- self.get_chunks(i, header, height)
- i.network.trigger_callback('updated')
+ if not self.get_and_verify_chunks(i, header, height):
+ continue
if height > self.local_height:
# get missing parts from interface (until it connects to my chain)
chain = self.get_chain( i, header )
# skip that server if the result is not consistent
- if not chain: continue
+ if not chain:
+ print_error('e')
+ continue
# verify the chain
if self.verify_chain( chain ):
print_error("height:", height, i.server)
for header in chain:
self.save_header(header)
- self.height = height
else:
print_error("error", i.server)
# todo: dismiss that server
+ continue
- i.network.trigger_callback('updated')
+ self.network.new_blockchain_height(height, i)
height = header.get('block_height')
prev_hash = self.hash_header(prev_header)
- bits, target = self.get_target(height/2016)
+ bits, target = self.get_target(height/2016, chain)
_hash = self.hash_header(header)
try:
assert prev_hash == header.get('prev_block_hash')
assert bits == header.get('bits')
- assert eval('0x'+_hash) < target
- except:
+ assert int('0x'+_hash,16) < target
+ except Exception:
return False
prev_header = header
_hash = self.hash_header(header)
assert previous_hash == header.get('prev_block_hash')
assert bits == header.get('bits')
- assert eval('0x'+_hash) < target
+ assert int('0x'+_hash,16) < target
previous_header = header
previous_hash = _hash
self.save_chunk(index, data)
print_error("validated chunk %d"%height)
-
- 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')
-
- prev_header = self.read_header(height -1)
- if not prev_header:
- # return False to request previous header
- return False
-
- 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
- except:
- # this can be caused by a reorg.
- print_error("verify header failed"+ repr(header))
- verifier.undo_verifications()
-
- # return False to request previous header.
- return False
-
- self.save_header(header)
- print_error("verify header:", _hash, height)
- return True
def header_to_string(self, res):
def header_from_string(self, s):
- hex_to_int = lambda s: eval('0x' + s[::-1].encode('hex'))
+ hex_to_int = lambda s: int('0x' + s[::-1].encode('hex'), 16)
h = {}
h['version'] = hex_to_int(s[0:4])
h['prev_block_hash'] = hash_encode(s[4:36])
socket.setdefaulttimeout(30)
print_error("downloading ", self.headers_url )
urllib.urlretrieve(self.headers_url, filename)
- except:
+ print_error("done.")
+ except Exception:
print_error( "download failed. creating file", filename )
open(filename,'wb+').close()
h = os.path.getsize(name)/80 - 1
if self.local_height != h:
self.local_height = h
- self.height = self.local_height
def read_header(self, block_height):
return h
- def get_target(self, index):
+ def get_target(self, index, chain=None):
+ if chain is None:
+ chain = [] # Do not use mutables as default values!
max_target = 0x00000000FFFF0000000000000000000000000000000000000000000000000000
if index == 0: return 0x1d00ffff, max_target
first = self.read_header((index-1)*2016)
last = self.read_header(index*2016-1)
-
+ if last is None:
+ for h in chain:
+ if h.get('block_height') == index*2016-1:
+ last = h
+
nActualTimespan = last.get('timestamp') - first.get('timestamp')
nTargetTimespan = 14*24*60*60
nActualTimespan = max(nActualTimespan, nTargetTimespan/4)
c = c[2:]
i -= 1
- c = eval('0x'+c[0:6])
- if c > 0x800000:
+ c = int('0x'+c[0:6],16)
+ if c >= 0x800000:
c /= 256
i += 1
return new_bits, new_target
- def request_header(self, i, h):
+ def request_header(self, i, h, queue):
print_error("requesting header %d from %s"%(h, i.server))
- i.send([ ('blockchain.block.get_header',[h])], 'get_header')
+ i.send([ ('blockchain.block.get_header',[h])], lambda i,r: queue.put((i,r)))
- def retrieve_header(self, i):
+ def retrieve_header(self, i, queue):
while True:
try:
- r = i.get_response('get_header',timeout=1)
+ ir = queue.get(timeout=1)
except Queue.Empty:
print_error('timeout')
continue
+ if not ir:
+ continue
+
+ i, r = ir
+
if r.get('error'):
print_error('Verifier received an error:', r)
continue
header = final_header
chain = [ final_header ]
requested_header = False
-
+ queue = Queue.Queue()
+
while self.is_running():
if requested_header:
- header = self.retrieve_header(interface)
+ header = self.retrieve_header(interface, queue)
if not header: return
chain = [ header ] + chain
requested_header = False
height = header.get('block_height')
previous_header = self.read_header(height -1)
if not previous_header:
- self.request_header(interface, height - 1)
+ self.request_header(interface, height - 1, queue)
requested_header = True
continue
prev_hash = self.hash_header(previous_header)
if prev_hash != header.get('prev_block_hash'):
print_error("reorg")
- self.request_header(interface, height - 1)
+ self.request_header(interface, height - 1, queue)
requested_header = True
continue
return chain
- def get_chunks(self, i, header, height):
- requested_chunks = []
+ def get_and_verify_chunks(self, i, header, height):
+
+ queue = Queue.Queue()
min_index = (self.local_height + 1)/2016
max_index = (height + 1)/2016
- for n in range(min_index, max_index + 1):
- print_error( "requesting chunk", n )
- i.send([ ('blockchain.block.get_chunk',[n])], 'get_header')
- requested_chunks.append(n)
- break
-
- while requested_chunks:
- try:
- r = i.get_response('get_header',timeout=1)
- except Queue.Empty:
+ n = min_index
+ while n < max_index + 1:
+ print_error( "Requesting chunk:", n )
+ r = i.synchronous_get([ ('blockchain.block.get_chunk',[n])])[0]
+ if not r:
continue
- if not r: continue
-
- if r.get('error'):
- print_error('Verifier received an error:', r)
- continue
-
- # 3. handle response
- method = r['method']
- params = r['params']
- result = r['result']
-
- if method == 'blockchain.block.get_chunk':
- index = params[0]
- self.verify_chunk(index, result)
- requested_chunks.remove(index)
-
-
-
-
-
+ try:
+ self.verify_chunk(n, r)
+ n = n + 1
+ except Exception:
+ print_error('Verify chunk failed!')
+ n = n - 1
+ if n < 0:
+ return False
+ return True