运行时错误：请求体不是JSON：'invalid json'

解决方案

1. 90% 成功率 在路由中处理JSON解析异常

   from starlette.responses import JSONResponse
   async def endpoint(request):
       try:
           data = await request.json()
       except ValueError:
           return JSONResponse({'error': 'Invalid JSON'}, status_code=400)

2. 85% 成功率 使用中间件验证请求体格式

   from starlette.middleware.base import BaseHTTPMiddleware
   class JSONValidationMiddleware(BaseHTTPMiddleware):
       async def dispatch(self, request, call_next):
           if request.headers.get('content-type') == 'application/json':
               body = await request.body()
               import json
               try:
                   json.loads(body)
               except json.JSONDecodeError:
                   return JSONResponse({'error': 'Invalid JSON'}, status_code=400)
           return await call_next(request)