79 lines
3.4 KiB
Python
79 lines
3.4 KiB
Python
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import functools
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import ipaddress
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from django.conf import settings
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def parse_region(raw, new_layout):
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"""ip2region 五段地区串 → {"country", "province", "city"}；不足 4 段/空串返回 None。
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两种数据布局（以 xdb 文件头的结构版本区分）：
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- 旧版 2.0 结构："国家|区域|省|市|ISP"，省=parts[2]、市=parts[3]；
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- 新版 3.0 结构（现行 v4/v6 库）："国家|省/区域|城市|ISP|国家代码"，
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省=parts[1]、市=parts[2]，ISP 段在 parts[3]——映射错位会把 ISP 串进 city。
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缺失段为 ip2region 的 "0" 占位，原样保留，由展示层决定如何呈现。
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"""
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parts = (raw or "").split("|")
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if len(parts) < 4:
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return None
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if new_layout:
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country, province, city = parts[0], parts[1], parts[2]
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else:
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country, province, city = parts[0], parts[2], parts[3]
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return {"country": country, "province": province, "city": city}
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class GeoResolver:
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"""离线 IP 地理解析（ip2region xdb，进程级单例）。
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py-ip2region 3.0.4 实际 API（以其源码为准，与官方旧 README 不同）：
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- ``searcher.new_with_buffer(version, c_buffer)`` 需要先传 ``util.IPv4``/``util.IPv6``
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版本对象（由 xdb 文件头 256 字节经 ``util.Header`` + ``util.version_from_header``
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探测；2.0 结构老库自动归为 IPv4）；
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- ``Searcher`` 不支持 with 上下文管理器（无 __enter__/__exit__）；
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- c_buffer 模式下 ``search(ip)`` 是纯内存切片（无文件 IO、无共享可变状态，
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官方声明线程安全），返回上述五段字符串。
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包缺失 / xdb 未下载 / 文件损坏时优雅降级：resolve 一律返回 None。
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"""
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def __init__(self):
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self._searcher = None
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self._new_layout = True
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try:
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from ip2region import searcher as ip2region_searcher
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from ip2region import util as ip2region_util
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with open(settings.IP2REGION_XDB, "rb") as f:
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buff = f.read()
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if len(buff) < ip2region_util.HeaderInfoLength:
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return # 文件过短，绝非合法 xdb
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header = ip2region_util.Header(buff[: ip2region_util.HeaderInfoLength])
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version = ip2region_util.version_from_header(header)
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if version is None:
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return # 无法识别的 xdb 结构/IP 版本
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# 结构版本同时决定数据段布局：2.0 旧布局 / 3.0 新布局
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self._new_layout = header.version >= ip2region_util.XdbStructure30
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self._searcher = ip2region_searcher.new_with_buffer(version, buff)
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except Exception:
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self._searcher = None
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@functools.lru_cache(maxsize=10000)
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def resolve(self, ip: str):
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"""返回 {"country", "province", "city"}，内网/环回/非法 IP 或降级时返回 None。
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结果被 lru_cache 缓存（键含 self，单例常驻故无泄漏问题），调用方勿修改返回的 dict。"""
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if not ip:
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return None
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try:
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if ipaddress.ip_address(ip).is_private:
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return None
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except ValueError:
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return None
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if not self._searcher:
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return None
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try:
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raw = self._searcher.search(ip)
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return parse_region(raw, self._new_layout)
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except Exception:
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return None
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