258 lines
9.6 KiB
Python
258 lines
9.6 KiB
Python
# gateway/app/middleware/auth.py - IMPROVED VERSION
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"""
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Enhanced Authentication Middleware for API Gateway
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Implements proper token validation and tenant context extraction
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"""
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import structlog
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from fastapi import Request, HTTPException
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from fastapi.responses import JSONResponse
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from starlette.middleware.base import BaseHTTPMiddleware
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from starlette.responses import Response
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import httpx
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from typing import Optional, Dict, Any
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import asyncio
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from app.core.config import settings
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from shared.auth.jwt_handler import JWTHandler
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logger = structlog.get_logger()
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# JWT handler for local token validation
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jwt_handler = JWTHandler(settings.JWT_SECRET_KEY, settings.JWT_ALGORITHM)
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# Routes that don't require authentication
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PUBLIC_ROUTES = [
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"/health",
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"/metrics",
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"/docs",
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"/redoc",
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"/openapi.json",
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"/api/v1/auth/login",
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"/api/v1/auth/register",
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"/api/v1/auth/refresh",
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"/api/v1/auth/verify"
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]
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class AuthMiddleware(BaseHTTPMiddleware):
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"""
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Enhanced Authentication Middleware following microservices best practices
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Responsibilities:
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1. Token validation (local first, then auth service)
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2. User context injection
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3. Tenant context extraction (per request)
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4. Rate limiting enforcement
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5. Request routing decisions
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"""
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def __init__(self, app, redis_client=None):
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super().__init__(app)
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self.redis_client = redis_client # For caching and rate limiting
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async def dispatch(self, request: Request, call_next) -> Response:
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"""Process request with enhanced authentication"""
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# Skip authentication for public routes
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if self._is_public_route(request.url.path):
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return await call_next(request)
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# Extract and validate JWT token
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token = self._extract_token(request)
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if not token:
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logger.warning(f"Missing token for protected route: {request.url.path}")
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return JSONResponse(
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status_code=401,
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content={"detail": "Authentication required"}
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)
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# Verify token and get user context
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user_context = await self._verify_token(token)
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if not user_context:
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logger.warning(f"Invalid token for route: {request.url.path}")
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return JSONResponse(
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status_code=401,
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content={"detail": "Invalid or expired token"}
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)
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# Extract tenant context from request (not from JWT)
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tenant_id = self._extract_tenant_from_request(request)
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# Verify user has access to tenant (if tenant_id provided)
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if tenant_id:
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has_access = await self._verify_tenant_access(user_context["user_id"], tenant_id)
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if not has_access:
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logger.warning(f"User {user_context['email']} denied access to tenant {tenant_id}")
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return JSONResponse(
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status_code=403,
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content={"detail": "Access denied to tenant"}
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)
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request.state.tenant_id = tenant_id
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# Inject user context into request
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request.state.user = user_context
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request.state.authenticated = True
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# Add user context to forwarded requests
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self._inject_auth_headers(request, user_context, tenant_id)
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logger.debug(f"Authenticated request: {user_context['email']} -> {request.url.path}")
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return await call_next(request)
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def _is_public_route(self, path: str) -> bool:
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"""Check if route requires authentication"""
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return any(path.startswith(route) for route in PUBLIC_ROUTES)
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def _extract_token(self, request: Request) -> Optional[str]:
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"""Extract JWT token from Authorization header"""
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auth_header = request.headers.get("Authorization")
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if auth_header and auth_header.startswith("Bearer "):
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return auth_header.split(" ")[1]
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return None
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def _extract_tenant_from_request(self, request: Request) -> Optional[str]:
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"""
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Extract tenant ID from request (NOT from JWT token)
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Priority order:
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1. X-Tenant-ID header
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2. tenant_id query parameter
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3. tenant_id in request path
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"""
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# Method 1: Header
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tenant_id = request.headers.get("X-Tenant-ID")
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if tenant_id:
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return tenant_id
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# Method 2: Query parameter
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tenant_id = request.query_params.get("tenant_id")
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if tenant_id:
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return tenant_id
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# Method 3: Path parameter (extract from URLs like /api/v1/tenants/{tenant_id}/...)
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path_parts = request.url.path.split("/")
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if "tenants" in path_parts:
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try:
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tenant_index = path_parts.index("tenants")
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if tenant_index + 1 < len(path_parts):
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return path_parts[tenant_index + 1]
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except (ValueError, IndexError):
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pass
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return None
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async def _verify_token(self, token: str) -> Optional[Dict[str, Any]]:
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"""
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Verify JWT token with fallback strategy:
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1. Local validation (fast)
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2. Auth service validation (authoritative)
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3. Cache valid tokens to reduce auth service calls
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"""
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# Step 1: Try local JWT validation first (fast)
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try:
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payload = jwt_handler.verify_token(token)
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if payload and self._validate_token_payload(payload):
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logger.debug("Token validated locally")
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return payload
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except Exception as e:
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logger.debug(f"Local token validation failed: {e}")
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# Step 2: Check cache for recently validated tokens
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if self.redis_client:
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try:
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cached_user = await self._get_cached_user(token)
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if cached_user:
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logger.debug("Token found in cache")
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return cached_user
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except Exception as e:
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logger.warning(f"Cache lookup failed: {e}")
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# Step 3: Verify with auth service (authoritative)
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try:
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user_context = await self._verify_with_auth_service(token)
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if user_context:
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# Cache successful validation
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if self.redis_client:
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await self._cache_user(token, user_context)
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logger.debug("Token validated by auth service")
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return user_context
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except Exception as e:
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logger.error(f"Auth service validation failed: {e}")
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return None
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def _validate_token_payload(self, payload: Dict[str, Any]) -> bool:
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"""Validate JWT payload has required fields"""
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required_fields = ["user_id", "email", "exp"]
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return all(field in payload for field in required_fields)
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async def _verify_with_auth_service(self, token: str) -> Optional[Dict[str, Any]]:
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"""Verify token with auth service"""
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try:
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async with httpx.AsyncClient(timeout=3.0) as client:
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response = await client.post(
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f"{settings.AUTH_SERVICE_URL}/api/v1/auth/verify",
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headers={"Authorization": f"Bearer {token}"}
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)
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if response.status_code == 200:
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return response.json()
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else:
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logger.warning(f"Auth service returned {response.status_code}")
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return None
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except asyncio.TimeoutError:
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logger.error("Auth service timeout")
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return None
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except Exception as e:
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logger.error(f"Auth service error: {e}")
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return None
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async def _verify_tenant_access(self, user_id: str, tenant_id: str) -> bool:
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"""Verify user has access to specific tenant"""
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try:
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async with httpx.AsyncClient(timeout=3.0) as client:
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response = await client.get(
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f"{settings.TENANT_SERVICE_URL}/api/v1/tenants/{tenant_id}/access/{user_id}"
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)
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return response.status_code == 200
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except Exception as e:
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logger.error(f"Tenant access verification failed: {e}")
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return False
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async def _get_cached_user(self, token: str) -> Optional[Dict[str, Any]]:
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"""Get user context from cache"""
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if not self.redis_client:
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return None
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cache_key = f"auth:token:{hash(token)}"
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cached_data = await self.redis_client.get(cache_key)
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if cached_data:
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import json
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return json.loads(cached_data)
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return None
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async def _cache_user(self, token: str, user_context: Dict[str, Any], ttl: int = 300):
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"""Cache user context for 5 minutes"""
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if not self.redis_client:
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return
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cache_key = f"auth:token:{hash(token)}"
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import json
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await self.redis_client.setex(cache_key, ttl, json.dumps(user_context))
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def _inject_auth_headers(self, request: Request, user_context: Dict[str, Any], tenant_id: Optional[str]):
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"""Inject authentication context into forwarded requests"""
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# Add user context headers for downstream services
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if hasattr(request, "headers"):
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# Create mutable headers
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headers = dict(request.headers)
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headers["X-User-ID"] = user_context["user_id"]
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headers["X-User-Email"] = user_context["email"]
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if tenant_id:
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headers["X-Tenant-ID"] = tenant_id
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# Update request headers
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request.scope["headers"] = [(k.lower().encode(), v.encode()) for k, v in headers.items()]
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