initial commit

README.md

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+# Update vote information
+
+- Requires a Bitcoin XT node running with this patch https://github.com/dgenr8/bitcoinxt/commit/62ec4ca3bba718668f0aab1dc5ff570f9441092f
+- Node must be configured with txindex=1
+- RPC username and password are assumed to be located at ../.bitcoin/bitcoin.conf
+
+Depends on pygtail, jinja2 and simplejson python libraries.
+
+On ubuntu:
+sudo apt-get install python3-pygtail, python3-jinja2, python3-simplejson
+
+Run doublespend.py to generate double spend data and update the static website.
+
+# The website
+The website itself consists of only static files. Point the webserver to serve files in folder site/
+

doublespend.py

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+import sys
+import time
+from respend.logparser import RespendChecker
+from respend.txdecoder import decode_tx
+from respend.blockchain import BlockchainChecker
+from respend.winnerupdater import update_winners
+from respend.txdata import store_respend
+from respend.websitebuilder import build_website
+
+TXDATA = "txdata"
+
+def on_respend_detected(tx1, tx2):
+    tx1_decoded = decode_tx(tx1.hex)
+    tx1_decoded['first_seen'] = tx1.time
+    tx2_decoded = decode_tx(tx2.hex)
+    tx2_decoded['first_seen'] = tx2.time
+
+    print("Wrote %s" % store_respend({
+        'first' : tx1_decoded,
+        'second' : tx2_decoded,
+        'timestamp' : tx1.time,
+        'winner' : None}))
+
+respend = RespendChecker(
+        logpath = "debug-sample.log",
+        on_respend = on_respend_detected)
+
+blockchain = BlockchainChecker(
+        on_new_tip = lambda: update_winners())
+
+while True:
+    update_website = respend.check()
+    update_website |= blockchain.check()
+    if update_website:
+        print("New changes. Updating website.")
+        build_website()
+
+    sys.stdout.write(".")
+    sys.stdout.flush()
+    time.sleep(1)

respend/blockchain.py

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+from respend.rpcutil import connection
+
+class BlockchainChecker:
+    def __init__(self, on_new_tip):
+        self.on_new_tip = on_new_tip
+        self.tip = None
+
+    def check(self):
+        new_tip = connection().getbestblockhash()
+        if new_tip == self.tip:
+            return False
+        print("New blockchain tip: %s" % new_tip)
+        self.tip = new_tip
+        return self.on_new_tip()

respend/logparser.py

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+import re
+from pygtail import Pygtail
+
+def regex_match(regex, line):
+    m = re.match(regex, line)
+    if m is None:
+        return m
+    return m.group(1);
+
+class RespendTx:
+    def __init__(self, time_regex, hex_regex):
+        self.time_regex = time_regex
+        self.hex_regex = hex_regex
+
+        self.time = None
+        self.hex = None
+
+    def parse_line(self, line):
+        t = regex_match(self.time_regex, line)
+        if t is not None:
+            self.time = t
+            print("matched %s %s" % (self.time_regex, line))
+
+        h = regex_match(self.hex_regex, line)
+        if h is not None:
+            self.hex = h
+            print("matched %s %s" % (self.hex_regex, line))
+
+    def done(self):
+        return self.time != None and self.hex != None
+
+    def clear(self):
+        self.time = self.hex = None
+
+class RespendChecker():
+    def __init__(self, logpath, on_respend):
+        self.logpath = logpath
+        self.on_respend = on_respend
+
+    def check(self):
+        tx1 = RespendTx(
+                time_regex = r'.*tx1: (\d{4}-\d{2}-\d{2} [0-9:]{8})',
+                hex_regex = r'.*tx1 hex: ([0-9a-f]+)')
+
+        tx2 = RespendTx(
+                time_regex = r'(\d{4}-\d{2}-\d{2} [0-9:]{8}) Respend tx2',
+                hex_regex = r'.*tx2 hex: ([0-9a-f]+)')
+
+        found = False
+        for line in Pygtail(self.logpath):
+            # tx2 is logged before tx1
+
+            if not tx2.done():
+                tx2.parse_line(line)
+
+            elif not tx1.done():
+                tx1.parse_line(line)
+
+            if tx1.done() and tx2.done():
+                print("found double spend")
+                self.on_respend(tx1, tx2)
+                tx1.clear()
+                tx2.clear()
+                found = True
+        return found

respend/rpcutil.py

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+import sys
+sys.path.append("./lib/bitcoinrpc")
+from bitcoinrpc.authproxy import AuthServiceProxy, JSONRPCException
+from functools import lru_cache
+
+def read_cfg(param):
+    cfglines = open("../.bitcoin/bitcoin.conf").readlines()
+    for c in cfglines:
+        if c.startswith(param):
+            return c[len(param) + 1:-1]
+    return None
+
+rpcuser = read_cfg("rpcuser")
+rpcpassword = read_cfg("rpcpassword")
+port = 8332
+
+url = "http://%s:%s@127.0.0.1:%s" % (rpcuser, rpcpassword, port)
+conn = AuthServiceProxy(url)
+
+def connection():
+    global conn
+    return conn
+
+@lru_cache(maxsize = 1024)
+def get_cached_tx(txid):
+    return connection().getrawtransaction(txid, 1)

respend/txdata.py

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+import simplejson as json
+import hashlib
+import glob
+import os
+
+TXDATA = "txdata"
+
+def has_winner(respend):
+    return respend['winner'] != None
+
+def list_respends():
+    return glob.glob(TXDATA + "/*.json")
+
+def load_respend(path):
+    with open(path) as fh:
+        return json.load(fh)
+
+def respend_id(txid_first, txid_second):
+    h = hashlib.new('ripemd160')
+    h.update(txid_first.encode() + txid_second.encode())
+    return h.hexdigest()
+
+def store_respend(respend):
+    rid = respend_id(respend['first']['txid'], respend['second']['txid'])
+    path = os.path.join(TXDATA, rid + ".json")
+    with open(path, "w") as fh:
+        json.dump(respend, fh, sort_keys = True, indent = 2 * ' ')
+    return path

respend/txdecoder.py

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+from respend.rpcutil import connection
+
+def decode_tx(hexstr):
+    return connection().decoderawtransaction(hexstr)