使用Web API调用下载文件

// 示例代码：使用Fetch API下载文件
fetch('https://example.com/path/to/file.pdf')
  .then(response => {
    if (!response.ok) {
      throw new Error('Network response was not ok ' + response.statusText);
    }
    return response.blob();
  })
  .then(blob => {
    const url = window.URL.createObjectURL(blob);
    const a = document.createElement('a');
    a.href = url;
    a.download = 'file.pdf';
    document.body.appendChild(a);
    a.click();
    a.remove();
    window.URL.revokeObjectURL(url);
  })
  .catch(error => {
    console.error('There has been a problem with your fetch operation:', error);
  });

// 示例代码：分块下载大文件
async function downloadFileInChunks(url, chunkSize = 1024 * 1024) {
  const response = await fetch(url);
  const reader = response.body.getReader();
  const contentLength = +response.headers.get('Content-Length');
  let receivedLength = 0;
  let chunks = [];

  while (true) {
    const { done, value } = await reader.read();
    if (done) {
      break;
    }
    chunks.push(value);
    receivedLength += value.length;
    console.log(`Received ${receivedLength} of ${contentLength}`);
  }

  const blob = new Blob(chunks);
  const url = window.URL.createObjectURL(blob);
  const a = document.createElement('a');
  a.href = url;
  a.download = 'largefile.zip';
  document.body.appendChild(a);
  a.click();
  a.remove();
  window.URL.revokeObject署URL(url);
}

downloadFileInChunks('https://example.com/path/to/largefile.zip');