thomasv
11 years ago
15 changed files with 738 additions and 640 deletions
@ -0,0 +1,329 @@ |
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#!/usr/bin/env python |
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# |
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# Electrum - lightweight Bitcoin client |
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# Copyright (C) 2012 thomasv@ecdsa.org |
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# |
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# This program is free software: you can redistribute it and/or modify |
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# it under the terms of the GNU General Public License as published by |
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# the Free Software Foundation, either version 3 of the License, or |
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# (at your option) any later version. |
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# |
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# This program is distributed in the hope that it will be useful, |
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# but WITHOUT ANY WARRANTY; without even the implied warranty of |
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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# GNU General Public License for more details. |
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# |
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# You should have received a copy of the GNU General Public License |
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# along with this program. If not, see <http://www.gnu.org/licenses/>. |
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import threading, time, Queue, os, sys, shutil |
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from util import user_dir, appdata_dir, print_error |
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from bitcoin import * |
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class BlockchainVerifier(threading.Thread): |
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""" Simple Payment Verification """ |
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def __init__(self, interface, config): |
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threading.Thread.__init__(self) |
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self.daemon = True |
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self.config = config |
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self.interface = interface |
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self.interface.register_channel('verifier') |
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self.lock = threading.Lock() |
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self.pending_headers = [] # headers that have not been verified |
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self.height = 0 |
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self.local_height = 0 |
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self.running = False |
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self.headers_url = 'http://headers.electrum.org/blockchain_headers' |
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def stop(self): |
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with self.lock: self.running = False |
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self.interface.poke('verifier') |
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def is_running(self): |
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with self.lock: return self.running |
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def run(self): |
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self.init_headers_file() |
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self.set_local_height() |
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with self.lock: |
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self.running = True |
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requested_chunks = [] |
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requested_headers = [] |
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all_chunks = False |
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# subscribe to block headers |
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self.interface.send([ ('blockchain.headers.subscribe',[])], 'verifier') |
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while self.is_running(): |
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# request missing chunks |
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if not all_chunks and self.height and not requested_chunks: |
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if self.local_height + 50 < self.height: |
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min_index = (self.local_height + 1)/2016 |
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max_index = (self.height + 1)/2016 |
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for i in range(min_index, max_index + 1): |
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print_error( "requesting chunk", i ) |
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self.interface.send([ ('blockchain.block.get_chunk',[i])], 'verifier') |
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requested_chunks.append(i) |
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break |
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else: |
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all_chunks = True |
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print_error("downloaded all chunks") |
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# process pending headers |
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if self.pending_headers and all_chunks: |
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done = [] |
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for header in self.pending_headers: |
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if self.verify_header(header): |
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done.append(header) |
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else: |
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# request previous header |
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i = header.get('block_height') - 1 |
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if i not in requested_headers: |
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print_error("requesting header %d"%i) |
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self.interface.send([ ('blockchain.block.get_header',[i])], 'verifier') |
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requested_headers.append(i) |
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# no point continuing |
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break |
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if done: |
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self.interface.trigger_callback('updated') |
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for header in done: |
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self.pending_headers.remove(header) |
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try: |
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r = self.interface.get_response('verifier',timeout=1) |
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except Queue.Empty: |
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continue |
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if not r: continue |
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if r.get('error'): |
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print_error('Verifier received an error:', r) |
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continue |
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# 3. handle response |
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method = r['method'] |
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params = r['params'] |
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result = r['result'] |
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if method == 'blockchain.block.get_chunk': |
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index = params[0] |
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self.verify_chunk(index, result) |
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requested_chunks.remove(index) |
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elif method in ['blockchain.headers.subscribe', 'blockchain.block.get_header']: |
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self.pending_headers.append(result) |
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if method == 'blockchain.block.get_header': |
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requested_headers.remove(result.get('block_height')) |
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else: |
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self.height = result.get('block_height') |
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## fixme # self.interface.poke('synchronizer') |
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self.pending_headers.sort(key=lambda x: x.get('block_height')) |
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# print "pending headers", map(lambda x: x.get('block_height'), self.pending_headers) |
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def verify_chunk(self, index, hexdata): |
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data = hexdata.decode('hex') |
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height = index*2016 |
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num = len(data)/80 |
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print_error("validating headers %d"%height) |
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if index == 0: |
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previous_hash = ("0"*64) |
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else: |
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prev_header = self.read_header(index*2016-1) |
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if prev_header is None: raise |
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previous_hash = self.hash_header(prev_header) |
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bits, target = self.get_target(index) |
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for i in range(num): |
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height = index*2016 + i |
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raw_header = data[i*80:(i+1)*80] |
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header = self.header_from_string(raw_header) |
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_hash = self.hash_header(header) |
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assert previous_hash == header.get('prev_block_hash') |
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assert bits == header.get('bits') |
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assert eval('0x'+_hash) < target |
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previous_header = header |
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previous_hash = _hash |
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self.save_chunk(index, data) |
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def verify_header(self, header): |
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# add header to the blockchain file |
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# if there is a reorg, push it in a stack |
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height = header.get('block_height') |
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prev_header = self.read_header(height -1) |
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if not prev_header: |
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# return False to request previous header |
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return False |
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prev_hash = self.hash_header(prev_header) |
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bits, target = self.get_target(height/2016) |
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_hash = self.hash_header(header) |
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try: |
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assert prev_hash == header.get('prev_block_hash') |
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assert bits == header.get('bits') |
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assert eval('0x'+_hash) < target |
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except: |
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# this can be caused by a reorg. |
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print_error("verify header failed"+ repr(header)) |
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# undo verifications |
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with self.lock: |
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items = self.verified_tx.items()[:] |
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for tx_hash, item in items: |
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tx_height, timestamp, pos = item |
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if tx_height >= height: |
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print_error("redoing", tx_hash) |
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with self.lock: |
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self.verified_tx.pop(tx_hash) |
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if tx_hash in self.merkle_roots: |
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self.merkle_roots.pop(tx_hash) |
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# return False to request previous header. |
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return False |
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self.save_header(header) |
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print_error("verify header:", _hash, height) |
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return True |
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def header_to_string(self, res): |
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s = int_to_hex(res.get('version'),4) \ |
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+ rev_hex(res.get('prev_block_hash')) \ |
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+ rev_hex(res.get('merkle_root')) \ |
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+ int_to_hex(int(res.get('timestamp')),4) \ |
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+ int_to_hex(int(res.get('bits')),4) \ |
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+ int_to_hex(int(res.get('nonce')),4) |
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return s |
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def header_from_string(self, s): |
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hex_to_int = lambda s: eval('0x' + s[::-1].encode('hex')) |
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h = {} |
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h['version'] = hex_to_int(s[0:4]) |
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h['prev_block_hash'] = hash_encode(s[4:36]) |
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h['merkle_root'] = hash_encode(s[36:68]) |
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h['timestamp'] = hex_to_int(s[68:72]) |
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h['bits'] = hex_to_int(s[72:76]) |
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h['nonce'] = hex_to_int(s[76:80]) |
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return h |
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def hash_header(self, header): |
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return rev_hex(Hash(self.header_to_string(header).decode('hex')).encode('hex')) |
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def path(self): |
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wdir = self.config.get('blockchain_headers_path', user_dir()) |
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if wdir and not os.path.exists( wdir ): os.mkdir(wdir) |
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return os.path.join( wdir, 'blockchain_headers') |
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def init_headers_file(self): |
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filename = self.path() |
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if os.path.exists(filename): |
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return |
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try: |
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import urllib, socket |
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socket.setdefaulttimeout(30) |
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print_error("downloading ", self.headers_url ) |
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urllib.urlretrieve(self.headers_url, filename) |
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except: |
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print_error( "download failed. creating file", filename ) |
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open(filename,'wb+').close() |
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def save_chunk(self, index, chunk): |
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filename = self.path() |
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f = open(filename,'rb+') |
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f.seek(index*2016*80) |
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h = f.write(chunk) |
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f.close() |
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self.set_local_height() |
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def save_header(self, header): |
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data = self.header_to_string(header).decode('hex') |
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assert len(data) == 80 |
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height = header.get('block_height') |
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filename = self.path() |
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f = open(filename,'rb+') |
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f.seek(height*80) |
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h = f.write(data) |
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f.close() |
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self.set_local_height() |
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def set_local_height(self): |
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name = self.path() |
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if os.path.exists(name): |
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h = os.path.getsize(name)/80 - 1 |
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if self.local_height != h: |
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self.local_height = h |
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def read_header(self, block_height): |
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name = self.path() |
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if os.path.exists(name): |
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f = open(name,'rb') |
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f.seek(block_height*80) |
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h = f.read(80) |
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f.close() |
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if len(h) == 80: |
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h = self.header_from_string(h) |
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return h |
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def get_target(self, index): |
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max_target = 0x00000000FFFF0000000000000000000000000000000000000000000000000000 |
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if index == 0: return 0x1d00ffff, max_target |
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first = self.read_header((index-1)*2016) |
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last = self.read_header(index*2016-1) |
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nActualTimespan = last.get('timestamp') - first.get('timestamp') |
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nTargetTimespan = 14*24*60*60 |
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nActualTimespan = max(nActualTimespan, nTargetTimespan/4) |
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nActualTimespan = min(nActualTimespan, nTargetTimespan*4) |
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bits = last.get('bits') |
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# convert to bignum |
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MM = 256*256*256 |
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a = bits%MM |
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if a < 0x8000: |
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a *= 256 |
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target = (a) * pow(2, 8 * (bits/MM - 3)) |
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# new target |
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new_target = min( max_target, (target * nActualTimespan)/nTargetTimespan ) |
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# convert it to bits |
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c = ("%064X"%new_target)[2:] |
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i = 31 |
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while c[0:2]=="00": |
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c = c[2:] |
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i -= 1 |
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c = eval('0x'+c[0:6]) |
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if c > 0x800000: |
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c /= 256 |
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i += 1 |
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new_bits = c + MM * i |
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return new_bits, new_target |
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@ -1,4 +1,4 @@ |
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ELECTRUM_VERSION = "1.9" # version of the client package |
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PROTOCOL_VERSION = '0.6' # protocol version requested |
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SEED_VERSION = 4 # bump this every time the seed generation is modified |
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SEED_VERSION = 5 # bump this every time the seed generation is modified |
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TRANSLATION_ID = 4101 # version of the wiki page |
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