Discussion with cache stale and network error

From what I understand from the documentation, when cachePolicy = cache-first and cacheLife > 0, the cached data is returned if it has not expired. If the cache has expired, a request is made on the server.

Doubt: If there is an error in the request (such as, for example, a cell phone went offline), the error is returned, but not the cache?

Another question, where is the cache? In memory? If I use the library in react native and place a 24-hour cache, after obtaining the data in a request I close the application and open it again, is a request made?

Another thing, how does the cache with pagination work? If the data is not stale, is only the first page returned?

That said, I would find it interesting that the library would allow:

1. Allow the creation of different forms of cache persistence, so someone could create a plugin for react-native that uses async-storage, for example
2. Add some configuration that allows the cache data to be returned when there is an error in the request
3. Add some return attribute of object response (such as loading, error …) that informs you if the data in question is new or is a cached data
4. Inform the time of the returned response. I think that’s possible, but I haven’t figured it out yet

[alex-cory]

I see what you’re saying. I like the idea of another cache policy. I will take a closer look at this as soon as I’m done with Suspense support.

I really appreciate this feedback!

In the meantime, feel free to poke around the library and submit a PR if you get to it before me!

Side note, I think I might still add the cache to the response because I think it might be useful for debugging purposes. What do you think?

[mogelbrod]

The cache-and-network policy would fit pretty well with this use case.

cacheLife could specify the TTL during which no additional network request needs to be made:

Cache strategy	No cached data	Fresh cache	Expired cache (via cacheLife)
apollo cache-and-network	loading + request	cached + request	(not supported)
use-http cache-first	loading + request	cached	loading(?) + request
use-http cache-and-network (proposed)	loading + request	cached	cached + request

Edit: Might be better to always return cached data via cachedData or similar, even if it is stale/expired. The behaviour above goes against the guarantee that cache-and-network always triggers a request:

However, regardless of whether or not the full data is in your cache this fetchPolicy will always execute query with the network interface…