59 lines
2.4 KiB
Python
59 lines
2.4 KiB
Python
from functools import lru_cache
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from fastapi import Depends, Request
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from fastapi.security import HTTPAuthorizationCredentials, HTTPBearer
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from app.core.config import get_settings
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from app.core.contracts import RequestContext
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from app.core.errors import UnauthorizedAgentError
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from app.core.security import JwtAuthenticator
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from app.service.identity_service import IdentityService
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_bearer = HTTPBearer(auto_error=False)
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# 与 `app/api/middleware.py` 的 `TRACE_ID_HEADER` 同名；认证阶段还不存在请求上下文，
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# 这个头是唯一可复用的追踪标识来源。
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TRACE_ID_HEADER = "X-Trace-ID"
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@lru_cache(maxsize=1)
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def _authenticator() -> JwtAuthenticator:
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return JwtAuthenticator(get_settings())
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async def build_request_context(
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request: Request,
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credentials: HTTPAuthorizationCredentials | None = Depends(_bearer), # noqa: B008
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) -> RequestContext:
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"""认证 + 身份解析。
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失败一律抛 `UnauthorizedAgentError`（`401 AUTHENTICATION_REQUIRED`），由
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`app/main.py` 的 `AgentError` 处理器输出文档 §3.4 的统一错误信封——此前这里抛
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FastAPI 原生 `HTTPException`，响应体是 `{"detail": "Unauthorized"}`，调用方无法用
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同一套信封解析。令牌非法与 RBAC/身份解析失败**仍不区分**，都返回 401。
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`meta.trace_id` 的来源（文档 §3.4）：此时请求上下文尚未建立，因此先记住请求头里的
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`X-Trace-ID`；没有就是空字符串，不凭空生成 id。
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"""
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request.state.trace_id = request.headers.get(TRACE_ID_HEADER)
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def unauthorized() -> UnauthorizedAgentError:
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"""消息固定成一句，涵盖令牌缺失、非法、过期、吊销与账号不可用。
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文档 §3.6 只给了一个 401 码，因此客户端无法（也不应）据 `message` 区分失败类型，
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更不会看到内部异常原文。
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"""
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return UnauthorizedAgentError("令牌缺失、无效或已吊销")
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if credentials is None or credentials.scheme.lower() != "bearer":
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raise unauthorized()
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try:
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context = _authenticator().authenticate(credentials.credentials)
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if "visitor" not in context.roles:
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context = await IdentityService().resolve(context)
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except Exception as exc:
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# 令牌非法、账号停用、角色读取失败一律按 401 处理，形态完全一致。
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raise unauthorized() from exc
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request.state.request_context = context
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return context
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