Issues with date starting on month 10

[bitadvisor]

Starting from 2012-10-01 we get the following error:

error: dynode.batchGetItem returned error: AmazonError - BatchGetItem 400 IncompleteSignatureException: Date must be in ISO-8601 'basic format'. Got '202201T000748Z'. See http://en.wikipedia.org/wiki/ISO_8601

Please note that the date is 202201 instead of 20121001. This is a variable type isue - number vs string - in aws-signer.js lines 65-70 and line 90.

To resolve, change line 90 to:

return n < 10 ? '0'+n : String(n);

[ryanfitz]

This is a major bug and here are more details.

i have been using dynode for a few months now to build a few node.js
systems that access dynamoDB. just a few hours ago, i noticed that
all of our systems using dynode started failing to connect to
dynamoDB. i went through your code and isolated this to a date string
conversion bug in lib/dynode/aws-signer.js. this bug only started
kicking in once the month turned double-digit, which by UTC time just
happened a few hours ago.

using this function as an example to explain the bug:

Signer._requestDate = function(date) {
return date.getUTCFullYear() +
pad(date.getUTCMonth()+1) +
pad(date.getUTCDate())+'T' +
pad(date.getUTCHours()) +
pad(date.getUTCMinutes()) +
pad(date.getUTCSeconds())+'Z';
}

each of these date.get*() functions return components that need to be
concatenated into the amazon date string, i.e. "2012101T023723Z". the
pad function called ahead checks for single-digit numbers and expands
them to have a '0' in front, as following:

function pad(n) {
return n<10 ? '0'+ n : n;
}

once the date becomes a double-digit number, it does not get converted
to a string as part of the padding, and as a result the "+" operator
adding month to year does a numerical addition, producing date strings
like "202201T023723Z". this is causing amazon to reject every dynode
request with errors like this:

{
"type": "InvalidSignatureException",
"serviceName": "com.amazon.coral.service",
"message": "Date in Credential scope does not match YYYYMMDD from
ISO-8601 version of date from HTTP: '202201' != '20121001', from
'20121001T024252Z'.",
"statusCode": 400,
"action": "DescribeTable",
"retry": false
}

if i understand the impact of this bug correctly, this will
immediately break all dynamoDB connections for anyone using dynode.

fortunately a fix can be made fairly simply by adding an explicitly
toString() conversion to the year in both parts of
lib/dynode/aws-signer.js that perform this operation:

Signer._requestDate = function(date) {
return (date.getUTCFullYear()).toString() +
pad(date.getUTCMonth()+1) +
pad(date.getUTCDate())+'T' +
pad(date.getUTCHours()) +
pad(date.getUTCMinutes()) +
pad(date.getUTCSeconds())+'Z';
};

function today(date) {
return (date.getUTCFullYear()).toString() +
pad(date.getUTCMonth()+1) + pad(date.getUTCDate());
}

[jacklevy]

actually on further review i think the solution proposed by psprindys is actually better. it ensures that pad() always returns a string, which is really a good post-condition for it. could prevent future similar bugs from further use of pad().