var url="http://ptx.transportdata.tw/MOTC/v2/Rail/TRA/Station?$format=JSON";取得所有火車站資訊
  var xdate=new Date().toGMTString();//驗證用時間
  var l2_id="xxxxxxxxxxxxxxxxxxx"; //申請到的id
  var l2_key="xxxxxxxxxxxxxxxxxxx"; //申請到的key
  //HMAC-SHA1 運算
  var signature = Utilities.computeHmacSignature(Utilities.MacAlgorithm.HMAC_SHA_1,"x-date: "+xdate,l2_key);//進行加密運算
  //轉成Base64
  var signatured=Utilities.base64Encode(signature);//結果轉64B
  var header = {
    'Accept': 'application/json',
    "Authorization": 'hmac username="'+l2_id+'",algorithm="hmac-sha1",headers="x-date",signature="'+signatured+'"',
    'x-date':xdate,
    'Accept-Encoding':'gzip'
  }//放入header 多注意Authorization是否排正確
  var options = {
    'headers': header,
    'method': 'get',
  }
  var getans=UrlFetchApp.fetch(url,options)//取得資料