PTT aid 跟 url 互相轉換的工具

ptt_aid_converter.py

import base64
import re

STANDARD_ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
CUSTOM_ALPHABET = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz-_"

ENCODE = str.maketrans(STANDARD_ALPHABET, CUSTOM_ALPHABET)
DECODE = str.maketrans(CUSTOM_ALPHABET, STANDARD_ALPHABET)


def base64_encode(s: str) -> str:
    return base64.b64encode(str.encode(s)).decode("utf-8").translate(ENCODE)


def base64_decode(s: str) -> str:
    return base64.b64decode(str.encode(s.translate(DECODE))).decode("utf-8")


def random_encode(s: str) -> str:
    return base64.b64encode(int(s, 16).to_bytes(3, "big")).decode("utf-8").translate(ENCODE)[2:]


def random_decode(s: str) -> str:
    s = "00" + s
    return str(hex(int.from_bytes(base64.b64decode(str.encode(s.translate(DECODE))), "big")))[2:].upper()


def timestamp_encode(s: str) -> str:
    return base64.b64encode(int(s, 10).to_bytes(6, "big")).decode("utf-8").translate(ENCODE)[2:]


def timestamp_decode(s: str) -> str:
    s = "00" + s
    return str(int.from_bytes(base64.b64decode(str.encode(s.translate(DECODE))), "big"))


def url2aid(url: str) -> str:
    # example M.1419434423.A.DF0.html
    # example https://www.ptt.cc/bbs/Steam/M.1592910404.A.AD6.html
    # example https://www.ptt.cc/man/C_Chat/DE98/DFF5/DB61/M.1419434423.A.DF0.html
    v1 = re.findall(r"(?<=[MG]\.)\d{10}", url, re.MULTILINE)[0]  # timestamp
    v2 = re.findall(r"(?<=\.A\.)[A-Fa-f0-9]{3}", url, re.MULTILINE)[0]  # random
    result = f"#{timestamp_encode(v1)}{random_encode(v2)}"

    s = url.split("/")
    if len(s) >= 4:
        result += f"({s[4]})"

    return result


def aid2fn(aid: str) -> str:
    v1 = re.findall(r"(?<=#)[0-9A-Za-z\-_]{8}", aid, re.MULTILINE)[0]

    _time = v1[:-2]
    _random = v1[-2:]

    result = f"M.{timestamp_decode(_time)}.A.{random_decode(_random)}.html"

    return result


def aid2url(aid: str) -> str:
    if "(" in aid:
        board = re.findall(r"(?<=\().+(?=\))", aid, re.MULTILINE)[0]
        result = f"https://www.ptt.cc/bbs/{board}/{aid2fn(aid)}"
    else:
        result = aid2fn(aid)
    return result