Razor Cut

function doGet(e) {
  var id = e.parameter.id;
  var file = DriveApp.getFileById(id);
  var blob = file.getBlob();
  var b64 = Utilities.base64Encode(blob.getBytes());
  return ContentService
    .createTextOutput(JSON.stringify({
      name: file.getName(),
      mimeType: blob.getContentType(),
      data: b64
    }))
    .setMimeType(ContentService.MimeType.JSON);
}