Dynamo Cache token validation and expiration

[buholzer]

Thanks so much for implementing the boilerplate, very helpful!

I saw that in the dynamo cache the existence of the token is not checked:

    const newRefreshToken = (data) => {
      const userId = data.Items[0].userId;
      const payload = data.Items[0].payload;

https://github.com/laardee/serverless-authentication-boilerplate/blob/master/authentication/lib/storage/dynamo/dynamoCache.js#L149

Added the following check:

  if (data.Count <= 0) return Promise.reject('Invalid token');

Also it looks like you can use expired tokens, the query does not restrict to expired=false:

      const params = {
        TableName: table,
        ProjectionExpression: '#token, #type, #userId',
        KeyConditionExpression: '#token = :token and #type = :type',
        ExpressionAttributeNames: {
          '#token': 'token',
          '#type': 'type',
          '#userId': 'userId'
        },
        ExpressionAttributeValues: {
          ':token': oldToken,
          ':type': 'REFRESH'
        }
      };

https://github.com/laardee/serverless-authentication-boilerplate/blob/master/authentication/lib/storage/dynamo/dynamoCache.js#L129

Changed params to:

      const params = {
        TableName: table,
        ProjectionExpression: '#token, #type, #userId, #expired',
        KeyConditionExpression: '#token = :token and #type = :type',
        FilterExpression: '#expired = :expired',
        ExpressionAttributeNames: {
          '#token': 'token',
          '#type': 'type',
          '#userId': 'userId',
          '#expired': 'expired'
        },
        ExpressionAttributeValues: {
          ':token': oldToken,
          ':type': 'REFRESH',
          ':expired': false
        }
      };