单请求断点续传

前端代码

// 单请求断点续传
    async upload_onec(file) {
      const reader = new FileReader();
      reader.onload = (e) => {
        const URL = "http://127.0.0.1:3000/api/upload_onec";
        const buffer = e.currentTarget.result;
        const view = new Uint8Array(buffer);
        const md5 = MD5(view.toString());
        // let params = { md5, filename: file.name };
        fetch(URL + "?md5=" + md5)
          .then((res) => res.json())
          .then(({ data }) => {
            this.uploadFile({ name: file.name, URL, buffer, md5, loaded: data.loaded });
          });
      };
      reader.readAsArrayBuffer(file);
    },
    uploadFile({ name, URL, buffer, md5, loaded }) {
      let xhr = new XMLHttpRequest();
      xhr.onreadystatechange = () => {
        if (xhr.readyState === 4 && xhr.status === 200) {
          const res = JSON.parse(xhr.responseText);
          console.log(res);
        }
      };
      xhr.open("POST", URL + `?filename=${name}&md5=${md5}`, true);
      xhr.setRequestHeader("token", "token");
      xhr.send(buffer.slice(loaded));
    }

后端nodejs代码

const PATH = require("path");
const { existsSync, statSync, writeFileSync, appendFileSync, renameSync } = require("fs");

const post = ({ req, config, api }) =>
  new Promise((resolve, reject) => {
    const { md5, filename } = req.query;
    const filepath = PATH.join(config.cacheFilePath, md5);
    const savepath = PATH.join(config.saveFilePath, filename);
    const savefilePath = PATH.join(config.savePath, filename);
    req.on("data", (chunk) => {
      console.log(chunk);
      if (existsSync(filepath)) {
        appendFileSync(filepath, chunk);
      } else {
        writeFileSync(filepath, chunk);
      }
    });
    req.on("end", () => {
      api.ApiMkdir(config.saveFilePath);
      renameSync(filepath, savepath);
      resolve(savefilePath);
    });
    req.on("error", err => {
      console.log("上传错误");
      reject(err)
    });
  });
const get = ({ req, config }) => {
  const { md5 } = req.query;
  const filepath = PATH.join(config.cacheFilePath, md5);
  if (existsSync(filepath)) {
    return statSync(filepath).size;
  } else {
    return 0;
  }
}

module.exports = { post, get }