mirror of
https://github.com/home-assistant/core
synced 2024-09-06 10:29:55 +02:00
76 lines
2.8 KiB
Python
76 lines
2.8 KiB
Python
"""Helpers to generate ulids."""
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from __future__ import annotations
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from random import getrandbits
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import time
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def ulid_hex() -> str:
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"""Generate a ULID in lowercase hex that will work for a UUID.
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This ulid should not be used for cryptographically secure
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operations.
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This string can be converted with https://github.com/ahawker/ulid
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ulid.from_uuid(uuid.UUID(ulid_hex))
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"""
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return f"{int(time.time()*1000):012x}{getrandbits(80):020x}"
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def ulid(timestamp: float | None = None) -> str:
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"""Generate a ULID.
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This ulid should not be used for cryptographically secure
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operations.
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01AN4Z07BY 79KA1307SR9X4MV3
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|----------| |----------------|
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Timestamp Randomness
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48bits 80bits
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This string can be loaded directly with https://github.com/ahawker/ulid
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import homeassistant.util.ulid as ulid_util
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import ulid
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ulid.parse(ulid_util.ulid())
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"""
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ulid_bytes = int((timestamp or time.time()) * 1000).to_bytes(
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6, byteorder="big"
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) + int(getrandbits(80)).to_bytes(10, byteorder="big")
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# This is base32 crockford encoding with the loop unrolled for performance
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#
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# This code is adapted from:
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# https://github.com/ahawker/ulid/blob/06289583e9de4286b4d80b4ad000d137816502ca/ulid/base32.py#L102
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#
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enc = "0123456789ABCDEFGHJKMNPQRSTVWXYZ"
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return (
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enc[(ulid_bytes[0] & 224) >> 5]
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+ enc[ulid_bytes[0] & 31]
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+ enc[(ulid_bytes[1] & 248) >> 3]
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+ enc[((ulid_bytes[1] & 7) << 2) | ((ulid_bytes[2] & 192) >> 6)]
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+ enc[((ulid_bytes[2] & 62) >> 1)]
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+ enc[((ulid_bytes[2] & 1) << 4) | ((ulid_bytes[3] & 240) >> 4)]
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+ enc[((ulid_bytes[3] & 15) << 1) | ((ulid_bytes[4] & 128) >> 7)]
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+ enc[(ulid_bytes[4] & 124) >> 2]
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+ enc[((ulid_bytes[4] & 3) << 3) | ((ulid_bytes[5] & 224) >> 5)]
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+ enc[ulid_bytes[5] & 31]
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+ enc[(ulid_bytes[6] & 248) >> 3]
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+ enc[((ulid_bytes[6] & 7) << 2) | ((ulid_bytes[7] & 192) >> 6)]
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+ enc[(ulid_bytes[7] & 62) >> 1]
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+ enc[((ulid_bytes[7] & 1) << 4) | ((ulid_bytes[8] & 240) >> 4)]
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+ enc[((ulid_bytes[8] & 15) << 1) | ((ulid_bytes[9] & 128) >> 7)]
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+ enc[(ulid_bytes[9] & 124) >> 2]
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+ enc[((ulid_bytes[9] & 3) << 3) | ((ulid_bytes[10] & 224) >> 5)]
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+ enc[ulid_bytes[10] & 31]
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+ enc[(ulid_bytes[11] & 248) >> 3]
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+ enc[((ulid_bytes[11] & 7) << 2) | ((ulid_bytes[12] & 192) >> 6)]
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+ enc[(ulid_bytes[12] & 62) >> 1]
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+ enc[((ulid_bytes[12] & 1) << 4) | ((ulid_bytes[13] & 240) >> 4)]
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+ enc[((ulid_bytes[13] & 15) << 1) | ((ulid_bytes[14] & 128) >> 7)]
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+ enc[(ulid_bytes[14] & 124) >> 2]
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+ enc[((ulid_bytes[14] & 3) << 3) | ((ulid_bytes[15] & 224) >> 5)]
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+ enc[ulid_bytes[15] & 31]
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)
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