Registration, Login and Forgot Password using Google Spreadsheet

TIMAI2 · December 29, 2023, 4:59pm

Try this:

Uses a javascript function to generate the hmacsha256 hash on the app side.

Only downside is that the reset password is sent in plain text in the email...

There are better password generators out there...

SCRIPT

function doPost(e) {

var ss = SpreadsheetApp.openById('YOUR SPREADSHEET ID HERE');
var sh = ss.getSheetByName("YOUR SHEET NAME HERE");
var msg;

if (e.parameter.fn == "getusers" ) {
   var loginData = sh.getDataRange().getValues();
   var users = [];
   for ( var i = 1; i < loginData.length; i++ ) {
   users.push(loginData[i][0]);
   }
     msg = JSON.stringify(users);
 }
else if ( e.parameter.fn == "register" ) {
    sh.appendRow([e.parameter.email,e.parameter.pass]);
    msg = "user registered";  
  }
else if ( e.parameter.fn == "login" ) {
  var loginData = sh.getDataRange().getValues();
   for ( var i = 0; i < loginData.length; i++ ) {
     if ( e.parameter.email == loginData[i][0] && e.parameter.pass == loginData[i][1] ) {
       msg = "user logged in";
     }
   }
}
else if ( e.parameter.fn == "reset" ) {
  var newpass = makePasswd();
  var newHash = makeHash(newpass,e.parameter.key);
  //change hash for email in sheet
  var loginData = sh.getDataRange().getValues();
   for ( var i = 0; i < loginData.length; i++ ) {
     if ( e.parameter.email == loginData[i][0]) {
      var rngp = sh.getRange(i+1,2);
      rngp.setValue(newHash);
       msg = "password reset";
     }
   }
  //send email with new password
  GmailApp.sendEmail(e.parameter.email,"From AI2 App","Your new password is: " + newpass + "\n\n Use this new password to login.\n\n Thank you.");
}
return ContentService.createTextOutput(msg);

}

function makePasswd() {
  var passwd = '';
  var chars = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!.#*@_';
  for (i=1;i<8;i++) {
    var c = Math.floor(Math.random()*chars.length + 1);
    passwd += chars.charAt(c)
  }
  return passwd;
}

function makeHash(message,key){
  var getHash = Utilities.computeHmacSha256Signature(message,key).reduce(function(str,chr){
  chr = (chr < 0 ? chr + 256 : chr).toString(16);
  return str + (chr.length==1?'0':'') + chr;
  },'');;
  return getHash;
}

BLOCKS

SPREADSHEET