Assumptions:

How to use this API:

• We need to create a token for each email we send, this will have all the params needs for NPS except a score:

Using NetPromoterScore.generate_token(touchpoint, respondent_class, respondent_id, rated_object_class, rated_object_id)

• We send this in the client , maybe as a query param or anything (that the client will post as a param in the post request)

The user submits the values to our api like this:

/api/v1/net_promotor_score?token=aksfiq3hdni12n3ic1jn2d.1md2hi12em1odnmi12bner1wd.... and a param of score

• we take the 2 params: score & token, parse the token and find the record with it's params, or create a new record in the NPS, then we add score to that and save to the DB

Known limitations:

Using the given params to the DB can be slow, it would be better to save in the NPS the following: score, touchpoint (enum or a ref on a touchpoint table), respondent_uuid, rated_uuid

with all the above numeric or UUID , we gain better performance and integrity

To overcome these limitations, I have added a caching for the nps_scores when retrieving, as 5 mins stale data won't be a problem (we need to check this assumption)

We can add a sensible expiry date for the tokens to avoid it being valid forever