JSON.parse() - SyntaxError: Expected end of stream at char 2

Question

In my project, I have written google spreadsheet script to decipher encrypted cell content using sjcl. But I failed.

function encryptCell() {
  var masterKey = Browser.inputBox('Enter masterKey');
  var spreadSheet = SpreadsheetApp.getActiveSpreadsheet();
  var cell = spreadSheet.getActiveSheet().getActiveCell();
  var input = cell.getValue();

  var encJson = sjcl.encrypt(masterKey, input);
/*
{"iv":"4psT+LTIh/aT7WWv7Ye7qw==","v":1,"iter":1000,"ks":128,"ts":64,"mode":"ccm","adata":"","cipher":"aes","salt":"PjSOiia9TCM=","ct":"3hwmBbwQ7y/fsjk="}
*/
  var encStr = JSON.stringify(encJson);
/*
"{\"iv\":\"4psT+LTIh/aT7WWv7Ye7qw==\",\"v\":1,\"iter\":1000,\"ks\":128,\"ts\":64,\"mode\":\"ccm\",\"adata\":\"\",\"cipher\":\"aes\",\"salt\":\"PjSOiia9TCM=\",\"ct\":\"3hwmBbwQ7y/fsjk=\"}"
*/
  var encB64 = Utilities.base64Encode(encStr);
  Browser.msgBox(encB64);

  var rencStr = Utilities.base64Decode(encB64);
/*
34,123,92,34,105,118,92,34,58,92,34,52,112,115,84,43,76,84,73,104,47,97,84,55,87,87,118,55,89,101,55,113,119,61,61,92,34,44,92,34,118,92,34,58,49,44,92,34,105,116,101,114,92,34,58,49,48,48,48,44,92,34,107,115,92,34,58,49,50,56,44,92,34,116,115,92,34,58,54,52,44,92,34,109,111,100,101,92,34,58,92,34,99,99,109,92,34,44,92,34,97,100,97,116,97,92,34,58,92,34,92,34,44,92,34,99,105,112,104,101,114,92,34,58,92,34,97,101,115,92,34,44,92,34,115,97,108,116,92,34,58,92,34,80,106,83,79,105,105,97,57,84,67,77,61,92,34,44,92,34,99,116,92,34,58,92,34,51,104,119,109,66,98,119,81,55,121,47,102,115,106,107,61,92,34,125,34
*/
  var rencJson = JSON.parse(rencStr);
  var rinput = sjcl.decrypt(masterKey, rencJson);
  Browser.msgBox(rinput);
}

Encryption is fine, which I can decrypt using this tool. Something is wrong with JSON.parse().

forgot to mention, I have included _sjcl.min.js_ contents into google script. — Nilesh, Sep 10 '15 at 06:56
Thanks @Corvusoft. solution is [here](http://stackoverflow.com/a/20210010/4417818) — Nilesh, Sep 10 '15 at 07:10

score 1 · Answer 1 · answered Sep 10 '15 at 07:09

  var rencStr = Utilities.base64Decode(encB64);
/*
34,123,92,34,105,118,92,34,58,92,34,52,112,115,84,43,76,84,73,104,47,97,84,55,87,87,118,55,89,101,55,113,119,61,61,92,34,44,92,34,118,92,34,58,49,44,92,34,105,116,101,114,92,34,58,49,48,48,48,44,92,34,107,115,92,34,58,49,50,56,44,92,34,116,115,92,34,58,54,52,44,92,34,109,111,100,101,92,34,58,92,34,99,99,109,92,34,44,92,34,97,100,97,116,97,92,34,58,92,34,92,34,44,92,34,99,105,112,104,101,114,92,34,58,92,34,97,101,115,92,34,44,92,34,115,97,108,116,92,34,58,92,34,80,106,83,79,105,105,97,57,84,67,77,61,92,34,44,92,34,99,116,92,34,58,92,34,51,104,119,109,66,98,119,81,55,121,47,102,115,106,107,61,92,34,125,34
*/

If you take a look, that's not JSON. did you possibly miss the JSON.stringify(); step for that one?

You can't parse it if it's not JSON.

score 1 · Answer 2 · answered Dec 09 '15 at 16:25

When decoding with Utilities.base64Decode() you have one extra step to follow if you want to get a string back. If you look at the Google Scripts reference it says that base64Decode returns a byte array and not a string. Looking at your code, your decode returns

var rencStr = Utilities.base64Decode(encB64);
/*34,123,92,34,105,118,92,34,58,92,34,52,112,115,84,43,76,84,73,104,47,97,84...*/

which is a numeric representation of your string in Unicode. If you run your return value through Utilities.newBlob(rencStr).getDataAsString() as the reference recommends, you will have your JSON that you can parse back into your encrypted string.

JSON.parse() - SyntaxError: Expected end of stream at char 2

2 Answers2