geolite-csv VS postgres-websockets

This is neat, and I tried going down the road of using Divisible for things years ago. This can be seem in a very old version of siphon's test suite. The data type for a CSV encoding has a trivial Divisible instance. However, as tekmo hints at in the post, the ergonomics of Divisible are pretty bad. Bad enough that I ended up just giving up on it (well, I had to decide if I wanted to swap the order of some type arguments to become a Profunctor, and I did not mourn the loss of the Divisible instance). Perhaps with the right syntactic sugar, it could be more useful.

At work, we've finally replaced a large part of a custom (mostly-)web backend with PostgREST recently, and that's quite a relief: considerably less code to maintain in that project now, and that was a rather awkward code. Something akin to PostgREST's "Embedding with Top-level Filtering" [1] had to be provided for all the tables, with OpenAPI schema and a typed API (Haskell + Servant); I avoided manually writing it all down, but at the cost of poking framework internals, and maintainability suffered. It was particularly annoying that the code doesn't really do anything useful, except for standing between a database and an HTTP client, and simply mimics the database anyway. Whenever a change had to be introduced, it was introduced into the database, the backend, and the frontend simultaneously, so it wasn't even useful for some kind of compatibility.

Now PostgREST handles all that, and only a few less trivial endpoints are handled by a custom backend (including streaming, which I'm considering replacing with postgrest-websocket [2] at some point).

During the switch to PostgREST, the encountered minor issues were those with inherited tables (had to set a bunch of computed/virtual columns [3] in order to "embed" those), and with a bug on filtering using such relations (turned out it was an already-fixed regression [4], so an update helped). Also a couple of helper stored procedures (to use via /rpc/) for updates in multiple tables at once (many-to-many relationships, to edit entities along with their relationships, using fewer requests) were added (though the old custom backend didn't have that), the security policies were set from the beginning, the frontend was rewritten (which allowed to finally switch without adding more work), so it was only left to cleanup the backend.

Not using views, since as mentioned above, database changes usually correspond to frontend changes, and the API doesn't have to be that stable yet.

Happy with it so far.

[1] https://postgrest.org/en/stable/api.html#embedding-with-top-...

[2] https://github.com/diogob/postgres-websockets

[3] https://postgrest.org/en/stable/api.html#computed-virtual-co...

[4] https://github.com/PostgREST/postgrest/issues/2530