js发送range+请求

async function fetchRange(url, start, end) {
  const response = await fetch(url, {
    headers: {
      'Range': `bytes=${start}-${end}`
    }
  });

  if (!response.ok) {
    throw new Error(`HTTP error! status: ${response.status}`);
  }

  const data = await response.blob();
  return data;
}

// 使用示例
fetchRange('https://example.com/largefile.mp4', 0, 1023)
  .then(data => {
    console.log('Received data:', data);
  })
  .catch(error => {
    console.error('Error fetching range:', error);
  });

async function getResourceSize(url) {
  const response = await fetch(url, { method: 'HEAD' });
  const contentLength = response.headers.get('Content-Length');
  return parseInt(contentLength, 10);
}

// 使用示例
getResourceSize('https://example.com/largefile.mp4')
  .then(size => {
    console.log('Resource size:', size);
    // 现在可以安全地发送 Range 请求
    return fetchRange('https://example.com/largefile.mp4', 0, size - 1);
  })
  .then(data => {
    console.log('Received data:', data);
  })
  .catch(error => {
    console.error('Error:', error);
  });