tx state API: cursor for paginated response

[CluEleSsUK]

Potential minor improvement : for a paginated response I would expect to receive back some kind of 'page cursor' that I could use in a subsequent request to get a following set of transactions.

For instance scrolling through a list, I might fetch the first 10, then the next 10, etc. The page cursor can make it easy to setup this kind of loop.

Originally posted by @andrewjslack in #177 (comment)

[andrewjslack]

how would you prefer this to be implemented? I could provide a new offset field, or I could provide a new query string with just offset/limit, or I could provide a full query string based on the last query with an increased offset.

daddygpt suggesting there some fancy hash-based cursors, but that seems like overkill. With just offset/page, we may duplicate some items as txs come in unless we order everything by time or similar and use time in the next cursor

Originally posted by @CluEleSsUK in #177 (comment)

That is exactly the issue which would make this a nice to have feature (: Offset will get unstable pretty quickly. I'm thinking ahead to when we might want to handle historic transaction lists for users.. Agree we don't need to complicate but longer term having something robust will be helpful if we are expecting significant transaction numbers to filter

Can we have something like - offset since last request_id?

/transactions?limit=20&since=request_12345

GPT suggesting to me too the best way to implement would be some kind of token:

Response:

{
  "items": [ /* txs */ ],
  "next_cursor": "opaque-token",
  "prev_cursor": "opaque-token",
  "has_more": true
}

Cursor:

{
  "sort": ["verified_time DESC", "request_id DESC"],
  "after": ["1761156070","0x882d...f056"],  // last (time, id) of this page
  "filters": { /* same query params client used */ }
}

[CluEleSsUK]

this is certainly doable but will require a bit more time because we need to think about ordering more in the state API - I'm not quite sure of the guarantees omnievent provides for tx ordering

[andrewjslack]

not urgent this week