Keep getting Timestamp error on Coinbase API Call

Question

I'm trying to connect my google sheet to Coinbase API using apps script. When I try to use the authentication with my keys, I keep getting the same error {"errors":[{"id":"authentication_error","message":"invalid timestamp"}]} code 401.

I try to check the time difference between my request and Coinbase server (to see if it is more than 30 seconds) and it doesn't. (1589465439 (mine) / 1589465464 (server) ).

so what can be wrong.

my code:

 var timestamp = Math.floor(Date.now() / 1000) + 15;

  Logger.log(timestamp);

  var req = {
    method: 'GET',
    path: '/v2/accounts',
    body: ''
  };

  var message = timestamp + req.method + req.path + req.body;
  var secret = Utilities.base64Decode(apiKey);
  secret = Utilities.newBlob(secret).getDataAsString();

  //create a hexedecimal encoded SHA256 signature of the message
  var hmac = Utilities.computeHmacSignature(Utilities.MacAlgorithm.HMAC_SHA_256, message, secret);
  var signature = Utilities.base64Encode(hmac);

  Logger.log(signature);

  var signatureStr = '';
    for (i = 0; i < signature.length; i++) {
      var byte = signature[i];
      if (byte < 0)
        byte += 256;
      var byteStr = byte.toString(16);
      // Ensure we have 2 chars in our byte, pad with 0
      if (byteStr.length == 1) byteStr = '0'+byteStr;
      signatureStr += byteStr;
    }  


  Logger.log(signatureStr);

  var options = {
    baseUrl: 'https://api.coinbase.com/',
    url: req.path,
    method: req.method,
    headers: {
        'CB-ACCESS-SIGN': signatureStr,
        'CB-ACCESS-TIMESTAMP': timestamp,
        'CB-ACCESS-KEY': apiKey
    }
  };



  var response = UrlFetchApp.fetch("https://api.coinbase.com/v2/accounts", options);

Thanks

user_1763756 · Answer

This is an old question, but in case it's still unsolved, I see a few changes that will fix this. I ran into a similar issue and had to solve it.

You should have 2 keys total (1 API key, 1 secret Key). Secret key is a separate key that comes from Coinbase, and is not a decoded variant of the API access key. It does not need explicit decoding.
Where you're passing timestamp as a header -> convert that value to a string to fix the timestamp error.

 headers: {
       'CB-ACCESS-SIGN': signatureStr,
       'CB-ACCESS-TIMESTAMP': timestamp.toString(),
       'CB-ACCESS-KEY': apiKey
    }

You can collapse the hmac and signature variables into this one liner before converting to hex.

 let signature = Utilities.computeHmacSha256Signature(message, secret);

These 3 changes make your code start to work with my keys.

Keep getting Timestamp error on Coinbase API Call

1 Answers