Feature: add hishel cache option `always_revalidate` by default

[ayussh-verma]

I wish to utilize the http_cache but with Hishel's always_revalidate set to true.
Hishel can be a bit aggressive with caching since it respects the max-age header which is usually 60 for GitHub's responses.
That means fresh data can only be pulled every 1 minute.

For my use-case, it would be better if I could only leverage Hishel's ETag caching to cache responses without exceeding ratelimits while still getting fresh data.

I think this is possible by creating a new cache control class and overriding the method for getting a controller, but that's inconvenient.

[yanyongyu]

You can use the cache_strategy option in githubkit to change the controller behavior like this:

from githubkit import GitHub
from githubkit.cache import MemCacheStrategy
from hishel import Controller


class MyCacheStrategy(MemCacheStrategy):
    def get_hishel_controller(self):
        # Custom controller here
        return Controller(always_revalidate=True)


g = GitHub(cache_strategy=MyCacheStrategy())

If you want a custom Hishel controller, i think it's better to create an issue at https://github.com/karpetrosyan/hishel .

[ayussh-verma]

Hi @yanyongyu, thanks - and yes, that method works but do you think this might be worth making this the default behavior or adding to the library itself? Since to me, it feels like this would be a (relatively) common requirement.

It's not a big deal but there's a problem with that method of creating a custom strategy which is that I have to be aware of the parent class' get_hishel_controller method in case there are any changes.

This is a slightly more future-proof way, but requires modifying private vars:

class MemCacheStrategyCustom(githubkit.cache.MemCacheStrategy):
    @t.override
    def get_hishel_controller(self) -> hishel.Controller:
        controller = super().get_hishel_controller()
        if controller is None:
            controller = hishel.Controller()

        controller._always_revalidate = True
        return controller

(E.g., the Redis strategy overrides the controller's key_generator)

[ayussh-verma]

Also, Hishel's GitHub example also sets revalidate to True: https://hishel.com/examples/github/

[yanyongyu]

From Hishel docs, the always_revalidate option is free and doesn't have a rate limit. I think this could be the default behavior 👍🏻 .