Save data to spreadsheet

FormGathererSpreadsheet.js

// https://script.google.com/macros/s/AKfycbxqaARMsIrSYKysoN5RByYe0PlWAgW9VrRi16p8IojhFKpgYpc/exec

function doGet(e){
  //return handleResponse(e);
}

function doPost(e){
  return handleResponse(e);
}

//  Sheet name where data is to be written
var SHEET_NAME = "database";
var SHEET_KEY  = "1HpzxBP34lAczWUFw8o7D5UINFDu3-jeTccs_3F6IgS4";

var SCRIPT_PROP = PropertiesService.getScriptProperties(); // new property service

function handleResponse(e) {
  // [1] http://googleappsdeveloper.blogspot.co.uk/2011/10/concurrency-and-google-apps-script.html
  // we want a public lock, one that locks for all invocations
  var lock = LockService.getPublicLock();
  lock.waitLock(30000);  // wait 30 seconds before conceding defeat.
  
  try {
    // next set where we write the data - you could write to multiple/alternate destinations
    var doc = SpreadsheetApp.openById(SHEET_KEY);
    var sheet = doc.getSheetByName(SHEET_NAME);
    
    // we'll assume header is in row 1 but you can override with header_row in GET/POST data
    var headRow = e.parameter.header_row || 1;
    var headers = sheet.getRange(1, 1, 1, sheet.getLastColumn()).getValues()[0];
    var nextRow = sheet.getLastRow()+1; // get next row
    var row = []; 
    // loop through the header columns
    for (i in headers) { 
      if (headers[i] == "email") {
          var email = e.parameter[headers[i]];
          var duplicate = checkDuplicateEmail(email);
          console.log(duplicate)
          if (duplicate) {
              console.log("Duplicate for ", email); 
              return ContentService
                  .createTextOutput(JSON.stringify({"result":"error", "error": "duplicate_email"}))
                  .setMimeType(ContentService.MimeType.JSON);
          }
      }
      
      if (headers[i] == "Timestamp"){ // special case if you include a 'Timestamp' column
        row.push(new Date());
      } else { // else use header name to get data
        row.push(e.parameter[headers[i]]);
      }
    }
    // more efficient to set values as [][] array than individually
    sheet.getRange(nextRow, 1, 1, row.length).setValues([row]);
    // return json success results
    return ContentService
          .createTextOutput(JSON.stringify({"result":"success", "row": nextRow}))
          .setMimeType(ContentService.MimeType.JSON);
  } catch(e){
    // if error return this
    return ContentService
          .createTextOutput(JSON.stringify({"result":"error", "error": e}))
          .setMimeType(ContentService.MimeType.JSON);
  } finally { //release lock
    lock.releaseLock();
  }
}

function testCheckDuplicateEmail() {
  var duplicate = checkDuplicateEmail("test@email.com");
  Logger.log(duplicate);
}

function checkDuplicateEmail(email) {
  var s = SpreadsheetApp.openById(SHEET_KEY);
  var emails = s.getRange("B2:B").getValues();
  
  Logger.log("Testing " + email);
  for (var i=0;i<emails.length;i++) { 
    if (emails[i][0] === email){
      return true
    }
  }
  
  //Do something when email not in the list
  return false
}

function setup() {
    var doc = SpreadsheetApp.getActiveSpreadsheet();
    SCRIPT_PROP.setProperty("key", doc.getId());
}