I am trying to make the primary key of my dynamodb table something like user_uuid. The user is being created in AWS Cognito and I can't seem to find a uuid like field as part of the CognitoUser class. I am trying to avoid using the username as the pk.
Can someone guide me to the right solution? I can't seem to find anything on the internet regarding a user_uuid field and for some reason I can't even find the documentation of CognitoUser class that is imported from "amazon-cognito-identity-js";
Depends if you plan to use email or phone as a 'username'. In that case, I would use the sub because it never changes. But, the sub is not k-sortable so that requires the use of an extra DB item and index/join to make users sortable by date added. If you plan to generate your GUID/KSUID, and only use email/phone as an alias, then I would use the 'username' as a common id between your DB and userpool.
Good luck with your project!
FWIW - the KSUID generators found in wild are massively overbuilt. 3000+ lines of code and 80+ dependencies. I made my own k-sortable and prefixed pseudo-random ID gen for Cognito users. Here's the code.
export function idGen(prefix: any) {
const validPrefix = [
'prefix1',
'prefix2'
];
//check if prefix argument is supplied
if (!prefix) {
return 'error! must supply prefix';
}
//check if value is a valid type
else if (validPrefix.indexOf(prefix) == -1) {
return 'error! prefix value supplied must be: ' + validPrefix;
} else {
// generate epoch time in seconds
const epoch = Math.round(Date.now() / 1000);
// convert epoch time to 6 character base36 string
const time = epoch.toString(36);
// generate 20 character base36 pseudo random string
const random =
Math.random().toString(36).substring(2, 12) +
Math.random().toString(36).substring(2, 12);
// combine prefix, strings, insert : divider and return id
return prefix + ':' + time + random;
}
}
Cognito user unique identifiers can be saved to a database using a combination of the "sub" value and the username, please refer to this question for a more lengthy discussion.
In the description of amazon-cognito-identity-js (found here, use case 5), they show how to get the userAttributes of a CognitoUser. One of the attributes is the sub value, which you can get at for example like this:
user.getUserAttributes(function(err, attributes) {
if (err) {
// Handle error
} else {
// Do something with attributes
const sub = attributes.find(obj => obj.Name === 'sub').Value;
}
});
I couldn't find any documentation on the available user attributes either, I recommend using the debugger to look at the user attributes returned from the function.
