Question

我正在做一个小脚本来下载带有节点的文件。我与网站的连接非常不稳定，通常会掉几次。我的想法是，如果连接在与以前相同的位置断开，则能够恢复下载。我使用axios和progress-stream：

const download = (link, size, localPath, transferred = 0) => {

  return new Promise((resolve, reject) => {

    axios({
      url: link,
      method: 'GET',
      responseType: 'stream'
    })
    .then(response => {

      const writer = fs.createWriteStream(localPath);

      const str = progress({
        time: 100,
        length: size,
        transferred: transferred
      });

      str.on('progress', function(progress) {
        console.log(progress);
      });

      response.data
        .pipe(str)
        .pipe(writer);

      writer.on('finish', resolve);
      writer.on('error', reject);

    })
    .catch(reject);

  });
};

当断开连接并重新运行脚本时，我将参数“ transfered”传入文件当前未完成但下载从0开始的大小。有没有办法在下载中断的地方开始下载？

Answer 1

与@Nick LeBlanc mentioned一样，您需要使用Range标头。

还请注意，fs.createWriteStream默认情况下使用'w'标志，该标志会在文件存在时将其截断。因此，您必须将其设置为'a'。

const download = (link, size, localPath, transferred = 0) => {

  return new Promise((resolve, reject) => {

    axios({
      url: link,
      method: 'GET',
      responseType: 'stream',
      headers: {
        Range: `bytes=${transferred}-`
      }
    })
    .then(response => {

      const writer = fs.createWriteStream(localPath, {flags: 'a'});

      const str = progress({
        time: 100,
        length: size,
        transferred: transferred
      });

      str.on('progress', function(progress) {
        console.log(progress);
      });

      response.data
        .pipe(str)
        .pipe(writer);

      writer.on('finish', resolve);
      writer.on('error', reject);

    })
    .catch(reject);

  });
};

节点还原流下载

1 个答案: