UniApp下载文件如何限制下载速度

// 下载函数，包含速度控制
function downloadFile(url, filePath, speedLimit) {
  let downloadedSize = 0;
  let startTime = Date.now();
  let lastDownloadTime = 0;
  let interval = 1000; // 默认每秒下载一次

  uni.request({
    url: url,
    method: 'GET',
    responseType: 'arraybuffer', // 必须是二进制数据
    stream: true, // 使用流式下载
    success: (res) => {
      let chunkSize = res.data.byteLength;
      let currentTime = Date.now();
      let timeDiff = currentTime - lastDownloadTime;

      // 节流控制，确保下载速度不超过限制
      if (timeDiff < interval) {
        setTimeout(() => {
          uni.writeFile({
            filePath: filePath,
            data: res.data,
            position: downloadedSize,
            success: () => {
              downloadedSize += chunkSize;
              lastDownloadTime = currentTime;
              if (res.header['content-length'] > downloadedSize) {
                downloadFile(url, filePath, speedLimit); // 递归下载
              } else {
                console.log('下载完成');
              }
            }
          });
        }, interval - timeDiff);
      } else {
        uni.writeFile({
          filePath: filePath,
          data: res.data,
          position: downloadedSize,
          success: () => {
            downloadedSize += chunkSize;
            lastDownloadTime = currentTime;
            if (res.header['content-length'] > downloadedSize) {
              downloadFile(url, filePath, speedLimit); // 递归下载
            } else {
              console.log('下载完成');
            }
          }
        });
      }
    },
    fail: (err) => {
      console.error('下载失败', err);
    }
  });
}

// 使用示例
let url = '你的下载链接';
let filePath = uni.env.USER_DATA_PATH + '/download.zip'; // 下载路径
let speedLimit = 1024 * 1024; // 限制速度为1MB/s (调整这个值)

downloadFile(url, filePath, speedLimit);