65 lines
1.9 KiB
Python
65 lines
1.9 KiB
Python
import hashlib
|
||
from sqlalchemy import Column, String
|
||
from sqlalchemy.orm import declarative_base, declared_attr
|
||
import ulid
|
||
|
||
Base = declarative_base()
|
||
|
||
# Base62 字符集
|
||
ALPHABET = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
|
||
|
||
|
||
def encode_base62(num: int) -> str:
|
||
"""将一个整数编码为 Base62 字符串"""
|
||
if num == 0:
|
||
return ALPHABET[0]
|
||
arr = []
|
||
base = len(ALPHABET)
|
||
while num:
|
||
num, rem = divmod(num, base)
|
||
arr.append(ALPHABET[rem])
|
||
return "".join(reversed(arr))
|
||
|
||
|
||
def encode_tablename_to_prefix(tablename: str, length: int = 3) -> str:
|
||
"""
|
||
将表名 encode 成固定长度的前缀，使用 MD5 拿到表名的唯一哈希值，转为整数后用 Base62 截取前 N 位
|
||
"""
|
||
# 计算表名的 MD5 哈希
|
||
hasher = hashlib.md5(tablename.encode("utf-8"))
|
||
hex_digest = hasher.hexdigest()
|
||
|
||
# 将十六进制哈希转为大整数
|
||
num = int(hex_digest, 16)
|
||
|
||
# 转为 Base62 字符串
|
||
b62_str = encode_base62(num)
|
||
|
||
# 截取固定长度（例如 3 位）作为该表的专属代码
|
||
return b62_str[:length]
|
||
|
||
|
||
def gen_convex_payload() -> str:
|
||
"""生成 128位 ULID 转 Base62 的趋势递增 Payload"""
|
||
u = ulid.new()
|
||
return encode_base62(u.int)
|
||
|
||
|
||
class AutoID:
|
||
"""
|
||
全自动 Convex 风格 ID 注入器
|
||
不再需要手动定义任何 prefix，全自动根据 __tablename__ 编码生成
|
||
"""
|
||
@declared_attr
|
||
def id(cls):
|
||
# 运行时动态获取子类的 __tablename__
|
||
tablename = cls.__tablename__
|
||
|
||
# 将表名编码为固定前缀（例如 "users" -> "7X1"）
|
||
table_prefix = encode_tablename_to_prefix(tablename, length=3)
|
||
|
||
# 核心工厂函数：拼接【编码后的表前缀】和【递增Payload】
|
||
def id_factory():
|
||
return f"{table_prefix}_{gen_convex_payload()}"
|
||
|
||
return Column(String(32), primary_key=True, default=id_factory) |