Fetch shouldn't be different from CF workers

[Aprillion]

There are differences in URL parsing and other aspects of fetch in CF workers and the specification. As of 2022-02-20, miniflare is using the standards-compliant undici implementation, not the CF implementation. We should switch to the CF version of fetch to improve DX (it's hard to debug issues that only happen in production and aren't reproducible locally).

See examples in cloudflare/cloudflare-docs#3578 (issue for documenting those differences, so developers can learn about those).

[hansede]

Cloudflare behaves like a reverse proxy, but Undici is not a reverse proxy, it's an HTTP client. I'm hoping we can get Cloudflare's actual fetch implementation in Miniflare, but in lieu of that a reverse proxy library like http-proxy-middleware could be a good alternative to Undici.

[mrbbot]

Hey! 👋 Thanks for raising this and apologies for the delayed response. Unfortunately, Cloudflare's fetch implementation isn't open-source and isn't designed to be integrated with Node.js. Cloudflare's fetch URL parser should soon be more spec-compliant though, so hopefully things will improve...

[mrbbot]

Hey! 👋 This issue should be fixed in Miniflare 3, which is powered by the open-source Workers runtime workerd.