API to fetch all the activities of users followed by a user

[yoavartzi]

We need an API call to populate the user feed. Currently, we display the recommendations from all users the user is following. We need an API call that fetches all activities by followed users, including both recommendations and reactions. The return schema of the API should support the different kinds of events it returns (recommendation and activities), in contrast to the current /recs/feeds API.

This API call must obey the cutoff date, so we shouldn't fetch recommendations that weren't posted yet. The API call should enable continuous scrolling with incremental fetching.

(before we execute this issue, please comment below on what is the API call we currently use to populate the user feed)

The API we are currently using is likely /recs/feeds. We need to replace it to /feeds or something like this, because it won't be just recommendation now, but all activities.

[zherujiang]

Yes, the API we currently use to get feeds is /recs/feeds. It passes parameters including the current page number, page size, cutoff time, and the userId. The backend looks up the users that the current user is following, then uses the cutoff time and its following user ids as a filter to get recs from these users.
I think the new GET /feeds API can follow a similar logic to create a filter using the following users and cutoff time, then we can use this filter to get recs as one part of the activities, and reactions as another part of the activities.