websocket sample code

websocket-sample.js

const ws = new WebSocket("ws://localhost:8000");
let certPromise = null;

const sendFile = () => new Promise((resolve) => {
  const reader = new FileReader();
  const file = document.getElementById('filename').files[0];
  reader.onload = (event) => {
    //发送文件
    ws.send(event.target.result);
    resolve(true);
  }
  reader.readAsArrayBuffer(file);
});

const requestCert = () => new Promise((resolve) => {
  // 请求证书
  const data = {}; // 
  fetch("http://localhost/api/cert", {
    body: JSON.stringify(data),
    credentials: 'same-origin',
    headers: {
      'content-type': 'application/json'
    },
    method: 'POST'
  }).then(res => {
    resolve(res.text());
  })
});

ws.onopen = () => {
  console.log("连接已打开");
  // 异步发送文件
  sendFile();
  // 申请证书
  certPromise = requestCert();
};

ws.onmessage = async (event) => {
  const message = JSON.parse(event.data);
  if (message.type === "FILE_RECEIVED") {
    const cert = await certPromise;
    ws.send(cert);
  } else if (message.type === "XXXX") {
    // to do
  }
};

ws.onclose = () => {
  console.log("连接已关闭");
};