feat(middleware): 添加HEAD请求中间件支持

添加HeadRequestMiddleware中间件，用于处理HEAD请求。该中间件将HEAD请求转换为GET请求并返回空响应体，同时保留状态码和头部信息，以符合HTTP规范要求。

app.py

@@ -16,7 +16,8 @@ import csv
 from io import StringIO
 from typing import Dict, List
 from starlette.middleware.base import BaseHTTPMiddleware
-from starlette.types import ASGIApp
+from starlette.types import ASGIApp, Message
+from typing import Optional, Dict, Any
 
 # Initialize GeoIP2 reader
 try:
@@ -99,6 +100,21 @@ class LanguageMiddleware(BaseHTTPMiddleware):
         
         return response
 
+class HeadRequestMiddleware(BaseHTTPMiddleware):
+    async def dispatch(self, request: Request, call_next):
+        if request.method == 'HEAD':
+            # Create a new request with GET method
+            request.scope['method'] = 'GET'
+            # Process the request as GET
+            response = await call_next(request)
+            # Create a new response with empty body
+            return Response(
+                status_code=response.status_code,
+                headers=response.headers,
+                media_type=response.media_type
+            )
+        return await call_next(request)
+
 class UserIdentityMiddleware(BaseHTTPMiddleware):
     def __init__(self, app: ASGIApp):
         super().__init__(app)
@@ -141,6 +157,7 @@ class UserIdentityMiddleware(BaseHTTPMiddleware):
 
 app = FastAPI()
 app.add_middleware(LanguageMiddleware)
+app.add_middleware(HeadRequestMiddleware)
 app.add_middleware(UserIdentityMiddleware)
 app.mount("/static", StaticFiles(directory="static"), name="static")
 templates = {}