Maybe provide a parameter to avoid browser caching for PyPI resolution requests

[CNSeniorious000]

Currently micropip passes a kwargs to pyfetch during resolution.

micropip/micropip/install.py

Line 138 in 5d4a869

fetch_kwargs=fetch_kwargs,

I think it is reasonable to add a no_cache parameter to install command or the Transaction class to skip browser caching. Currently it is not possible to skip browser caching for PyPI simple API calls.

Use case: upgrading a previously installed package

[ryanking13]

Thanks @CNSeniorious000! I can think of two ways to implement this.

1. adding a cache parameter as you suggest.
2. adding a headers parameter that users can pass arbitrary request headers when calling fetch. For instance, people can do headers={'cache': 'no-store'} or headers={'cache': "no-cache"} to pass cache-related parameters.

The second option would provide more flexibility, but it would also leak the internal implementation of micropip.install. WDYT?

[CNSeniorious000]

But cache: "no-cache" parameter is fetch's kwargs instead of the headers. Do you mean exposing a **fetch_kwargs in micropip.install?

And then here we don't need to init the fetch_kwargs with an empty dict:

micropip/micropip/install.py

Lines 116 to 118 in 5d4a869

	fetch_kwargs = dict()

[ryanking13]

Oh yes, fetch_kwargs is what I meant, not headers.

[CNSeniorious000]

One more question. If I specify cache='no-cache' in **fetch_kwargs, both the resolution step and the downloading step will skip the cache. But I think whl urls should be fetched with force-cache instead. Is there a way to allow customizing the two fetch kwargs separately?

[ryanking13]

Is there a way to allow customizing the two fetch kwargs separately?

I don't think we have such an option now, but I think it is reasonable. This may be something that we need to consider when re-designing the micropip module (#112) cc: @RulerOfCakes