資訊猿

開發 Line 機器人最重要的就是寫 web hook
那 webhook 就必須找個 server 來存放
可以免費放 webhook 的有 MS Azure, Amazon, Google Cloud... 等服務商
這些都要另外註冊帳號、設定 server 、可能還有期限流量等限制

用 google script 不須經過這些設定
就能直接編寫接收 line 訊息並回傳的機器人

以下範例為取得聊天室 ID 或 UserID
只要取得這些 ID 就能發送 push 訊息到這些 ID 的聊天視窗了

function doPost(e) {
  var urlReply = 'https://api.line.me/v2/bot/message/reply';
  var urlPush = 'https://api.line.me/v2/bot/message/push';
  var myGroup = 'XXXXXXX';         // push 訊息到這個 ID
  var send_message = 'doPost message';
  var strSourceType = "";
  var strNewRoomID = "";
  var strNewGroupID = "";
  var strNewUserID = "";
  
  var recieveData= JSON.parse(e.postData.contents);
  if (recieveData.events[0].type == "join")
  {
    if ( recieveData.events[0].source.type == "room" )
    {
      strSourceType = "room";
      strNewRoomID = recieveData.events[0].source.roomId;
      strNewUserID = recieveData.events[0].source.userId;
    }
    else if ( recieveData.events[0].source.type == "group" )
    {
      strSourceType = "group";
      strNewGroupID = recieveData.events[0].source.groupId;
      strNewUserID = recieveData.events[0].source.userId;
    }
    else if ( recieveData.events[0].source.type == "user" )
    {
      strSourceType = "user";
      strNewUserID = recieveData.events[0].source.userId;
    }
    
    send_message = "SourceType:" + strSourceType;
    send_message = send_message + " RoomID:" + strNewRoomID;
    send_message = send_message + " GroupID:" + strNewGroupID;
    send_message = send_message + " UserID:" + strNewUserID;
    UrlFetchApp.fetch(urlPush, {
      'headers': {
        'Content-Type': 'application/json; charset=UTF-8',
        'Authorization': 'Bearer ' + CHANNEL_ACCESS_TOKEN,
      },
      'method': 'post',
      'payload': JSON.stringify({
        'to': myGroup,
        'messages': [{
          'type': 'text',
          'text': send_message,
        }],
      }),
    });
  }
}

第一次要取得當下聊天視窗的ID
可以用reply的方式回應到當下的視窗
reply不需要輸入userID或groupID就能回傳到當下聊天視窗的ID

UrlFetchApp.fetch(urlReply, {
      'headers': {
        'Content-Type': 'application/json; charset=UTF-8',
        'Authorization': 'Bearer ' + CHANNEL_ACCESS_TOKEN,
      },
      'method': 'post',
      'payload': JSON.stringify({
        'messages': [{
          'type': 'text',
          'text': send_message,
        }],
      }),
    });