如何添加自定义中间件

langgraph new --template=new-langgraph-project-python my_new_project

# ./src/agent/webapp.py
from fastapi import FastAPI, Request
from starlette.middleware.base import BaseHTTPMiddleware

app = FastAPI()

class CustomHeaderMiddleware(BaseHTTPMiddleware):
    async def dispatch(self, request: Request, call_next):
        response = await call_next(request)
        response.headers['X-Custom-Header'] = 'Hello from middleware!'
        return response

# 将中间件添加到应用
app.add_middleware(CustomHeaderMiddleware)

{
  "dependencies": ["."],
  "graphs": {
    "agent": "./src/agent/graph.py:graph"
  },
  "env": ".env",
  "http": {
    "app": "./src/agent/webapp.py:app"
  }
  // 其他配置选项，如 auth、store 等。
}

{
  "dependencies": ["."],
  "graphs": {
    "agent": "./src/agent/graph.py:graph"
  },
  "env": ".env",
  "http": {
    "app": "./src/agent/webapp.py:app",
    "middleware_order": "auth_first"
  },
  "auth": {
    "path": "./auth.py:my_auth"
  }
}

langgraph dev --no-browser