万字长文，一篇吃透WebSocket：概念、原理、易错常识、动手实践(27)

const server = http.createServer((req, res) => {
res.writeHead(200, { "Content-Type": "text/plain; charset=utf-8"});
res.end("大家好，我是阿宝哥。感谢你阅读“你不知道的WebSocket”");
});
server.on("upgrade", function(req, socket) {
socket.on("data", (buffer) => {
const message = parseMessage(buffer);
if(message) {
console.log("Message from client:" message);
socket.write(constructReply({ message }));
} else if(message === null) {
console.log("WebSocket connection closed by the client.");
}
});
if(req.headers["upgrade"] !== "websocket") {
socket.end("HTTP/1.1 400 Bad Request");
return;
}
// 读取客户端提供的Sec-WebSocket-Key
const secWsKey = req.headers["sec-websocket-key"];
// 使用SHA-1算法生成Sec-WebSocket-Accept
const hash = generateAcceptValue(secWsKey);
// 设置HTTP响应头
const responseHeaders = [
"HTTP/1.1 101 Web Socket Protocol Handshake",
"Upgrade: WebSocket",
"Connection: Upgrade",