function doGet(e){
  Logger.log("--- doGet ---");

 var tag = "",
     value = "";

  try {

    // this helps during debuggin
    if (e == null){e={}; e.parameters = {tag:"test",value:"-1"};}

    tag = e.parameters.tag;
    value = e.parameters.value;

    // save the data to spreadsheet
    save_data(tag, value);


    return ContentService.createTextOutput("Wrote:\n  tag: " + tag + "\n  value: " + value);

  } catch(error) {
    Logger.log(error);
    return ContentService.createTextOutput("oops...." + error.message
                                            + "\n" + new Date()
                                            + "\ntag: " + tag +
                                            + "\nvalue: " + value);
  }
}

// Method to save given data to a sheet
function save_data(tag, value){
  Logger.log("--- save_data ---");


  try {
    var dateTime = new Date();

    // Paste the URL of the Google Sheets starting from https thru /edit
    // For e.g.: https://docs.google.com/..../edit
    var ss = SpreadsheetApp.openByUrl("https://docs.google.com/spreadsheets/d/1QnTT18fdBRw_mkN28bhb0fLbeX682U2LiYNQsgktkyc/edit");
    var dataLoggerSheet = ss.getSheetByName("DataCollector");


    // Get last edited row from DataLogger sheet
    var row = dataLoggerSheet.getLastRow() + 1;


    // Start Populating the data
    dataLoggerSheet.getRange("A" + row).setValue(row -1); // ID
    dataLoggerSheet.getRange("B" + row).setValue(dateTime); // dateTime
    dataLoggerSheet.getRange("C" + row).setValue(tag); // tag
    dataLoggerSheet.getRange("D" + row).setValue(value); // value


    // Update summary sheet
    summarySheet.getRange("B1").setValue(dateTime); // Last modified date
    // summarySheet.getRange("B2").setValue(row - 1); // Count
  }

  catch(error) {
    Logger.log(JSON.stringify(error));
  }

  Logger.log("--- save_data end---");
}