Inside Bitcoin

1#!/usr/bin/env python3
2# Copyright (c) 2020-present The Bitcoin Core developers
3# Distributed under the MIT software license, see the accompanying
4# file COPYING or http://www.opensource.org/licenses/mit-license.php.
5
6import argparse
7import io
8import requests
9import subprocess
10import sys
11import xml.etree.ElementTree
12
13DEFAULT_GLOBAL_FAUCET = 'https://signetfaucet.com/claim'
14DEFAULT_GLOBAL_CAPTCHA = 'https://signetfaucet.com/captcha'
15GLOBAL_FIRST_BLOCK_HASH = '00000086d6b2636cb2a392d45edc4ec544a10024d30141c9adf4bfd9de533b53'
16
17# braille unicode block
18BASE = 0x2800
19BIT_PER_PIXEL = [
20    [0x01, 0x08],
21    [0x02, 0x10],
22    [0x04, 0x20],
23    [0x40, 0x80],
24]
25BW = 2
26BH = 4
27
28# imagemagick or compatible fork (used for converting SVG)
29CONVERT = 'convert'
30
31class PPMImage:
32    '''
33    Load a PPM image (Pillow-ish API).
34    '''
35    def __init__(self, f):
36        if f.readline() != b'P6\n':
37            raise ValueError('Invalid ppm format: header')
38        line = f.readline()
39        (width, height) = (int(x) for x in line.rstrip().split(b' '))
40        if f.readline() != b'255\n':
41            raise ValueError('Invalid ppm format: color depth')
42        data = f.read(width * height * 3)
43        stride = width * 3
44        self.size = (width, height)
45        self._grid = [[tuple(data[stride * y + 3 * x:stride * y + 3 * (x + 1)]) for x in range(width)] for y in range(height)]
46
47    def getpixel(self, pos):
48        return self._grid[pos[1]][pos[0]]
49
50def print_image(img, threshold=128):
51    '''Print black-and-white image to terminal in braille unicode characters.'''
52    x_blocks = (img.size[0] + BW - 1) // BW
53    y_blocks = (img.size[1] + BH - 1) // BH
54
55    for yb in range(y_blocks):
56        line = []
57        for xb in range(x_blocks):
58            ch = BASE
59            for y in range(BH):
60                for x in range(BW):
61                    try:
62                        val = img.getpixel((xb * BW + x, yb * BH + y))
63                    except IndexError:
64                        pass
65                    else:
66                        if val[0] < threshold:
67                            ch |= BIT_PER_PIXEL[y][x]
68            line.append(chr(ch))
69        print(''.join(line))
70
71parser = argparse.ArgumentParser(description='Script to get coins from a faucet.', epilog='You may need to start with double-dash (--) when providing bitcoin-cli arguments.')
72parser.add_argument('-c', '--cmd', dest='cmd', default='bitcoin-cli', help='bitcoin-cli command to use')
73parser.add_argument('-f', '--faucet', dest='faucet', default=DEFAULT_GLOBAL_FAUCET, help='URL of the faucet')
74parser.add_argument('-g', '--captcha', dest='captcha', default=DEFAULT_GLOBAL_CAPTCHA, help='URL of the faucet captcha, or empty if no captcha is needed')
75parser.add_argument('-a', '--addr', dest='addr', default='', help='Bitcoin address to which the faucet should send')
76parser.add_argument('-p', '--password', dest='password', default='', help='Faucet password, if any')
77parser.add_argument('-n', '--amount', dest='amount', default='0.001', help='Amount to request (0.001-0.1, default is 0.001)')
78parser.add_argument('-i', '--imagemagick', dest='imagemagick', default=CONVERT, help='Path to imagemagick convert utility')
79parser.add_argument('bitcoin_cli_args', nargs='*', help='Arguments to pass on to bitcoin-cli (default: -signet)')
80
81args = parser.parse_args()
82
83if args.bitcoin_cli_args == []:
84    args.bitcoin_cli_args = ['-signet']
85
86
87def bitcoin_cli(rpc_command_and_params):
88    argv = [args.cmd] + args.bitcoin_cli_args + rpc_command_and_params
89    try:
90        return subprocess.check_output(argv).strip().decode()
91    except FileNotFoundError:
92        raise SystemExit(f"The binary {args.cmd} could not be found")
93    except subprocess.CalledProcessError:
94        cmdline = ' '.join(argv)
95        raise SystemExit(f"-----\nError while calling {cmdline} (see output above).")
96
97
98if args.faucet.lower() == DEFAULT_GLOBAL_FAUCET:
99    # Get the hash of the block at height 1 of the currently active signet chain
100    curr_signet_hash = bitcoin_cli(['getblockhash', '1'])
101    if curr_signet_hash != GLOBAL_FIRST_BLOCK_HASH:
102        raise SystemExit('The global faucet cannot be used with a custom Signet network. Please use the global signet or setup your custom faucet to use this functionality.\n')
103else:
104    # For custom faucets, don't request captcha by default.
105    if args.captcha == DEFAULT_GLOBAL_CAPTCHA:
106        args.captcha = ''
107
108if args.addr == '':
109    # get address for receiving coins
110    args.addr = bitcoin_cli(['getnewaddress', 'faucet', 'bech32'])
111
112data = {'address': args.addr, 'password': args.password, 'amount': args.amount}
113
114# Store cookies
115# for debugging: print(session.cookies.get_dict())
116session = requests.Session()
117
118if args.captcha != '': # Retrieve a captcha
119    try:
120        res = session.get(args.captcha)
121        res.raise_for_status()
122    except requests.exceptions.RequestException as e:
123        raise SystemExit(f"Unexpected error when contacting faucet: {e}")
124
125    # Size limitation
126    svg = xml.etree.ElementTree.fromstring(res.content)
127    if svg.attrib.get('width') != '150' or svg.attrib.get('height') != '50':
128        raise SystemExit("Captcha size doesn't match expected dimensions 150x50")
129
130    # Convert SVG image to PPM, and load it
131    try:
132        rv = subprocess.run([args.imagemagick, 'svg:-', '-depth', '8', 'ppm:-'], input=res.content, check=True, capture_output=True)
133    except FileNotFoundError:
134        raise SystemExit(f"The binary {args.imagemagick} could not be found. Please make sure ImageMagick (or a compatible fork) is installed and that the correct path is specified.")
135
136    img = PPMImage(io.BytesIO(rv.stdout))
137
138    # Terminal interaction
139    print_image(img)
140    print(f"Captcha from URL {args.captcha}")
141    data['captcha'] = input('Enter captcha: ')
142
143try:
144    res = session.post(args.faucet, data=data)
145except Exception:
146    raise SystemExit(f"Unexpected error when contacting faucet: {sys.exc_info()[0]}")
147
148# Display the output as per the returned status code
149if res:
150    # When the return code is in between 200 and 400 i.e. successful
151    print(res.text)
152elif res.status_code == 404:
153    print('The specified faucet URL does not exist. Please check for any server issues/typo.')
154elif res.status_code == 429:
155    print('The script does not allow for repeated transactions as the global faucet is rate-limited to 1 request/IP/day. You can access the faucet website to get more coins manually')
156else:
157    print(f'Returned Error Code {res.status_code}\n{res.text}\n')
158    print('Please check the provided arguments for their validity and/or any possible typo.')
159