Proxy-fs

[cadorn]

I want to be able to instanciate a proxy fs where the proxy loads and caches all lower level FS data as methods are called on the proxy object.

I want to then serialize the proxy data to a file and later instanciate a mock-fs object with it.

The idea is that I can pass a virtual FS object to a library, record all FS data needed while library executes and on second run feed the cached FS to the library instead of a real FS.

How would this fit into the q-io ecosystem?

[kriskowal]

@cadorn It would be very similar to fs-mock https://github.com/kriskowal/q-io/blob/master/fs-mock.js. It would be fine in a separate package or even here. You will find that it would be cohesive with a bunch of the Q-IO internals.

[kriskowal]

@cadorn Have you moved on this, or is it something you’re still looking for?

[cadorn]

Not yet.

I have started some work on shadowing FS calls so you can get events for paths being used: https://github.com/pinf/pinf-for-nodejs/blob/9f31624eeb4aecbd819893c55872a602f2b00389/lib/vfs.js

I'll be combining shadow-fs with a proxy-fs and another proxy I already have for HTTP[S] requests. The goal is to record all assets used by a package during build and at runtime. All this should have a callback and promise interface.

[cadorn]

The well-tested HTTP[S] caching proxy is here: https://github.com/sourcemint/util-js/blob/master/lib/url-proxy-cache.js
It works by keeping an additional meta file per URI. I hope to use the same approach for proxy-fs and re-use the same cache logic.