Inside Bitcoin

1#!/usr/bin/env python3
2#
3# linearize-hashes.py:  List blocks in a linear, no-fork version of the chain.
4#
5# Copyright (c) 2013-present The Bitcoin Core developers
6# Distributed under the MIT software license, see the accompanying
7# file COPYING or http://www.opensource.org/licenses/mit-license.php.
8#
9
10from http.client import HTTPConnection
11import json
12import re
13import base64
14import sys
15import os
16import os.path
17
18settings = {}
19
20class BitcoinRPC:
21    def __init__(self, host, port, username, password):
22        authpair = "%s:%s" % (username, password)
23        authpair = authpair.encode('utf-8')
24        self.authhdr = b"Basic " + base64.b64encode(authpair)
25        self.conn = HTTPConnection(host, port=port, timeout=30)
26
27    def execute(self, obj):
28        try:
29            self.conn.request('POST', '/', json.dumps(obj),
30                { 'Authorization' : self.authhdr,
31                  'Content-type' : 'application/json' })
32        except ConnectionRefusedError:
33            print('RPC connection refused. Check RPC settings and the server status.',
34                  file=sys.stderr)
35            return None
36
37        resp = self.conn.getresponse()
38        if resp is None:
39            print("JSON-RPC: no response", file=sys.stderr)
40            return None
41
42        body = resp.read().decode('utf-8')
43        resp_obj = json.loads(body)
44        return resp_obj
45
46    @staticmethod
47    def build_request(idx, method, params):
48        obj = { 'version' : '1.1',
49            'method' : method,
50            'id' : idx }
51        if params is None:
52            obj['params'] = []
53        else:
54            obj['params'] = params
55        return obj
56
57    @staticmethod
58    def response_is_error(resp_obj):
59        return 'error' in resp_obj and resp_obj['error'] is not None
60
61def get_block_hashes(settings, max_blocks_per_call=10000):
62    rpc = BitcoinRPC(settings['host'], settings['port'],
63             settings['rpcuser'], settings['rpcpassword'])
64
65    height = settings['min_height']
66    while height < settings['max_height']+1:
67        num_blocks = min(settings['max_height']+1-height, max_blocks_per_call)
68        batch = []
69        for x in range(num_blocks):
70            batch.append(rpc.build_request(x, 'getblockhash', [height + x]))
71
72        reply = rpc.execute(batch)
73        if reply is None:
74            print('Cannot continue. Program will halt.')
75            return None
76
77        for x,resp_obj in enumerate(reply):
78            if rpc.response_is_error(resp_obj):
79                print('JSON-RPC: error at height', height+x, ': ', resp_obj['error'], file=sys.stderr)
80                sys.exit(1)
81            assert resp_obj['id'] == x  # assume replies are in-sequence
82            if settings['rev_hash_bytes'] == 'true':
83                resp_obj['result'] = bytes.fromhex(resp_obj['result'])[::-1].hex()
84            print(resp_obj['result'])
85
86        height += num_blocks
87
88def get_rpc_cookie():
89    # Open the cookie file
90    with open(os.path.join(os.path.expanduser(settings['datadir']), '.cookie'), 'r') as f:
91        combined = f.readline()
92        combined_split = combined.split(":")
93        settings['rpcuser'] = combined_split[0]
94        settings['rpcpassword'] = combined_split[1]
95
96if __name__ == '__main__':
97    if len(sys.argv) != 2:
98        print("Usage: linearize-hashes.py CONFIG-FILE")
99        sys.exit(1)
100
101    with open(sys.argv[1]) as f:
102        for line in f:
103            # skip comment lines
104            m = re.search(r'^\s*#', line)
105            if m:
106                continue
107
108            # parse key=value lines
109            m = re.search(r'^(\w+)\s*=\s*(\S.*)$', line)
110            if m is None:
111                continue
112            settings[m.group(1)] = m.group(2)
113
114    if 'host' not in settings:
115        settings['host'] = '127.0.0.1'
116    if 'port' not in settings:
117        settings['port'] = 8332
118    if 'min_height' not in settings:
119        settings['min_height'] = 0
120    if 'max_height' not in settings:
121        settings['max_height'] = 313000
122    if 'rev_hash_bytes' not in settings:
123        settings['rev_hash_bytes'] = 'false'
124
125    use_userpass = True
126    use_datadir = False
127    if 'rpcuser' not in settings or 'rpcpassword' not in settings:
128        use_userpass = False
129    if 'datadir' in settings and not use_userpass:
130        use_datadir = True
131    if not use_userpass and not use_datadir:
132        print("Missing datadir or username and/or password in cfg file", file=sys.stderr)
133        sys.exit(1)
134
135    settings['port'] = int(settings['port'])
136    settings['min_height'] = int(settings['min_height'])
137    settings['max_height'] = int(settings['max_height'])
138
139    # Force hash byte format setting to be lowercase to make comparisons easier.
140    settings['rev_hash_bytes'] = settings['rev_hash_bytes'].lower()
141
142    # Get the rpc user and pass from the cookie if the datadir is set
143    if use_datadir:
144        get_rpc_cookie()
145
146    get_block_hashes(settings)
147