Dealing with cursors in ConnectionField resolve functions

In the Star Wars relay example, it looks like you expect the resolve_ships method of the Faction class to return every ship. While this is feasible with a small dataset like that, it’s not an assumption you can make. Does the resolve function get access to the first and after argument? Also, how do we supply pagination info?

Looking at the code, it looks like connection_from_list deals with the resolved data as a complete list. Is there a way to get around this? If the resolve function only gets the arguments, but no way to supply pagination info, should we just return 1 more object than was requested, so that connection_from_list knows there’s more and can correctly create the pagination info?

[syrusakbary]

Hi @bigblind, connection_from_list expect an iterable (this iterable had to implement len and a item getter like iterable[20:30] though). Could be a list, could be a lazy list, or anything that you could iter through. However, we don’t iter through the iterable until the end (when we show the results).

In the example of Starwars relay the resolve_ships return a complete list. But the swapi example the method returns an iterable.

So, for example, when you are using django querysets, the list is only “resolved” (aka queried in the DB) when we iter though it (when we return the resolved result), and after the list is sliced.

So it will already do in the most optimal way 😃

[jkimbo]

Hi @bigblind . We’re currently going through old issues that appear to have gone stale (ie. not updated in about the last 6 months) to try and clean up the issue tracker. If this is still important to you please comment and we’ll re-open this.

Thanks!