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Authenticated Downloads

Pass custom headers to download protected files using the requestOptions parameter.

await ExpoQuickLook.previewFile({
  uri: 'https://api.example.com/documents/123/download',
  requestOptions: {
    headers: {
      Authorization: `Bearer ${token}`,
    },
  },
});

Custom Headers​

The requestOptions.headers field accepts any Record<string, string>. Common use cases:

// Bearer token
requestOptions: {
  headers: {
    Authorization: `Bearer ${accessToken}`,
  },
}

// API key
requestOptions: {
  headers: {
    'X-API-Key': apiKey,
  },
}

// Multiple headers
requestOptions: {
  headers: {
    Authorization: `Bearer ${token}`,
    'X-Request-ID': requestId,
  },
}

Handling Auth Errors​

When authentication fails (401/403), the promise rejects with an HTTP error:

try {
  await ExpoQuickLook.previewFile({
    uri: 'https://api.example.com/documents/123',
    requestOptions: {
      headers: { Authorization: `Bearer ${token}` },
    },
  });
} catch (error) {
  if (error.message.includes('401')) {
    // Token expired — refresh and retry
    const newToken = await refreshToken();
    await ExpoQuickLook.previewFile({
      uri: 'https://api.example.com/documents/123',
      requestOptions: {
        headers: { Authorization: `Bearer ${newToken}` },
      },
    });
  }
}

Multi-File Preview with Auth​

Authentication headers also work with previewFiles on iOS:

await ExpoQuickLook.previewFiles({
  uris: [
    'https://api.example.com/documents/1',
    'https://api.example.com/documents/2',
  ],
  requestOptions: {
    headers: { Authorization: `Bearer ${token}` },
  },
});

The same headers are used for all files in the list.