SSE-DEMO/backend/p04.py

"""
FastAPI HTTP 代理服务
代理 HTTP://192.168.0.42:8005/mcp 接口
"""
import httpx
from fastapi import FastAPI, Request, Response
from fastapi.responses import StreamingResponse
import json

app = FastAPI(
    title="HTTP Proxy Service",
    description="代理 MCP 接口到 192.168.0.42:8005",
    version="1.0.0"
)

# 目标服务地址
TARGET_BASE_URL = "http://192.168.0.42:8005"


def get_forwarded_headers(request: Request) -> dict:
    """获取需要转发的 headers"""
    headers = {}
    # 转发所有 headers，跳过一些不需要的
    skip_headers = {"host", "content-length", "transfer-encoding"}
    
    for key, value in request.headers.items():
        if key.lower() not in skip_headers:
            headers[key] = value
    
    return headers


async def proxy_request(path: str, request: Request):
    """代理请求到目标服务"""
    url = f"{TARGET_BASE_URL}{path}"
    method = request.method
    headers = get_forwarded_headers(request)
    
    # 获取请求体
    body = await request.body()
    
    async with httpx.AsyncClient(timeout=60.0) as client:
        try:
            # 发送请求
            response = await client.request(
                method=method,
                url=url,
                headers=headers,
                content=body if body else None,
                params=request.query_params
            )
            
            # 构建响应头
            response_headers = {}
            for key, value in response.headers.items():
                if key.lower() not in {"content-length", "transfer-encoding", "connection"}:
                    response_headers[key] = value
            
            # 返回响应
            return Response(
                content=response.content,
                status_code=response.status_code,
                headers=response_headers
            )
            
        except httpx.TimeoutException:
            return Response(
                content=json.dumps({"error": "请求超时"}).encode("utf-8"),
                status_code=504,
                media_type="application/json"
            )
        except httpx.ConnectError:
            return Response(
                content=json.dumps({"error": "无法连接到目标服务"}).encode("utf-8"),
                status_code=503,
                media_type="application/json"
            )
        except Exception as e:
            return Response(
                content=json.dumps({"error": f"代理请求失败: {str(e)}"}).encode("utf-8"),
                status_code=500,
                media_type="application/json"
            )


@app.api_route("/mcp/{path:path}", methods=["GET", "POST", "PUT", "DELETE", "PATCH", "OPTIONS"])
async def proxy_mcp(path: str, request: Request):
    """代理 /mcp 路径下的所有请求"""
    target_path = f"/mcp/{path}"
    return await proxy_request(target_path, request)


@app.api_route("/{path:path}", methods=["GET", "POST", "PUT", "DELETE", "PATCH", "OPTIONS"])
async def proxy_all(path: str, request: Request):
    """代理所有其他路径的请求"""
    return await proxy_request(f"/{path}", request)



if __name__ == "__main__":
    import uvicorn
    uvicorn.run("p04:app", host="0.0.0.0", port=8000, reload=True)