用python实现http路由转发

当本地存在8081端口的情况下，8080端口接收请求转发到8081端口

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import http.server
import socketserver
import socket
import requests
# from urllib.parse import urlparse


# 检查端口是否被占用
def is_port_in_use(port):
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
        try:
            s.bind(("localhost", port))
            return False
        except OSError:
            return True


# 自定义请求处理器
class ProxyHandler(http.server.SimpleHTTPRequestHandler):
    def forward_request(self, method):
        # 构造目标 URL，将请求转发到 8081 端口
        target_url = f"http://localhost:8081{self.path}"

        # 获取请求头
        headers = {key: value for key, value in self.headers.items()}

        # 处理请求体（如果有）
        content_length = int(self.headers.get('Content-Length', 0))
        body = self.rfile.read(content_length) if content_length > 0 else None

        try:
            # 根据请求方法转发请求
            if method == "GET":
                response = requests.get(target_url, headers=headers, timeout=5)
            elif method == "POST":
                response = requests.post(target_url, headers=headers, data=body, timeout=5)
            else:
                self.send_error(405, "Method Not Allowed")
                return

            # 发送响应状态码
            self.send_response(response.status_code)
            # 发送响应头
            for key, value in response.headers.items():
                self.send_header(key, value)
            self.end_headers()
            # 发送响应内容
            self.wfile.write(response.content)

        except requests.RequestException as e:
            self.send_error(502, f"Bad Gateway: {str(e)}")

    def do_GET(self):
        if is_port_in_use(8081):
            self.forward_request("GET")
        else:
            self.send_response(200)
            self.send_header("Content-type", "text/plain")
            self.end_headers()
            self.wfile.write(b"Port 8081 is not available, handling request at 8080")

    def do_POST(self):
        if is_port_in_use(8081):
            self.forward_request("POST")
        else:
            self.send_response(200)
            self.send_header("Content-type", "text/plain")
            self.end_headers()
            self.wfile.write(b"Port 8081 is not available, handling request at 8080")



def live_listen():
    # 设置服务器
    PORT = 8080
    Handler = ProxyHandler

    # 使用 ThreadingTCPServer 支持并发请求
    with socketserver.ThreadingTCPServer(("", PORT), Handler) as httpd:
        print(f"Serving on port {PORT}")
        try:
            httpd.serve_forever()
        except KeyboardInterrupt:
            print("\nServer stopped")
            httpd.server_close()