mirror of
https://github.com/lnbits/lnbits-legend.git
synced 2024-11-19 18:11:30 +01:00
9e90aabead
- extensions are now blueprints: keep views, templastes and statics in the same folder
- increase app security using `flask-talisman`
- whenever possible use {{ url_for }} for links between pages
- remove references to non-existing JavaScript code
- add missing favicon.ico
108 lines
2.9 KiB
Python
108 lines
2.9 KiB
Python
import bitstring
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import re
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from binascii import hexlify
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from bech32 import bech32_decode, CHARSET
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class Invoice(object):
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def __init__(self):
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self.payment_hash: str = None
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self.amount_msat: int = 0
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self.description: str = None
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def decode(pr: str) -> Invoice:
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""" Super naïve bolt11 decoder,
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only gets payment_hash, description/description_hash and amount in msatoshi.
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based on https://github.com/rustyrussell/lightning-payencode/blob/master/lnaddr.py
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"""
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hrp, data = bech32_decode(pr)
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if not hrp:
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raise ValueError("Bad bech32 checksum")
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if not hrp.startswith("ln"):
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raise ValueError("Does not start with ln")
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data = u5_to_bitarray(data)
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# Final signature 65 bytes, split it off.
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if len(data) < 65 * 8:
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raise ValueError("Too short to contain signature")
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data = bitstring.ConstBitStream(data[: -65 * 8])
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invoice = Invoice()
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m = re.search("[^\d]+", hrp[2:])
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if m:
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amountstr = hrp[2 + m.end() :]
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if amountstr != "":
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invoice.amount_msat = unshorten_amount(amountstr)
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# pull out date
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data.read(35).uint
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while data.pos != data.len:
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tag, tagdata, data = pull_tagged(data)
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data_length = len(tagdata) / 5
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if tag == "d":
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invoice.description = trim_to_bytes(tagdata).decode("utf-8")
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elif tag == "h" and data_length == 52:
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invoice.description = hexlify(trim_to_bytes(tagdata)).decode("ascii")
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elif tag == "p" and data_length == 52:
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invoice.payment_hash = hexlify(trim_to_bytes(tagdata)).decode("ascii")
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return invoice
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def unshorten_amount(amount: str) -> int:
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""" Given a shortened amount, return millisatoshis
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"""
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# BOLT #11:
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# The following `multiplier` letters are defined:
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#
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# * `m` (milli): multiply by 0.001
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# * `u` (micro): multiply by 0.000001
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# * `n` (nano): multiply by 0.000000001
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# * `p` (pico): multiply by 0.000000000001
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units = {
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"p": 10 ** 12,
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"n": 10 ** 9,
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"u": 10 ** 6,
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"m": 10 ** 3,
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}
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unit = str(amount)[-1]
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# BOLT #11:
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# A reader SHOULD fail if `amount` contains a non-digit, or is followed by
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# anything except a `multiplier` in the table above.
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if not re.fullmatch("\d+[pnum]?", str(amount)):
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raise ValueError("Invalid amount '{}'".format(amount))
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if unit in units:
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return int(amount[:-1]) * 100_000_000_000 / units[unit]
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else:
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return int(amount) * 100_000_000_000
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def pull_tagged(stream):
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tag = stream.read(5).uint
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length = stream.read(5).uint * 32 + stream.read(5).uint
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return (CHARSET[tag], stream.read(length * 5), stream)
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def trim_to_bytes(barr):
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# Adds a byte if necessary.
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b = barr.tobytes()
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if barr.len % 8 != 0:
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return b[:-1]
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return b
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def u5_to_bitarray(arr):
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ret = bitstring.BitArray()
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for a in arr:
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ret += bitstring.pack("uint:5", a)
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return ret
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