Support Cloudflare pages/workers

I have a project that’s deployed to Cloudflare. The runtime environment behaves like a service worker, so it has fetch but not window, hence getting this error:

ReferenceError: window is not defined
    at node_modules/isomorphic-form-data/lib/browser.js

There’s a PR to fix isomorphic-form-data, I doubt it’s getting merged: https://github.com/form-data/isomorphic-form-data/pull/6

There’s also no XHR (some specific technical reasons for that), so importing masto/fetch also fails:

TypeError: globalThis.XMLHttpRequest is not a constructor
    at node_modules/rollup-plugin-node-polyfills/polyfills/http-lib/capability.js

I wonder if there’s an easy fix here, maybe a bundle that doesn’t use any polyfills?

[neet]

Thank you for explaining. I thought it was about FromData, but now I understand it is Mastodon’s undocumented behaviour. I don’t know it if is intended, but as you described, setting Content-Type to multipart/form-data doesn’t seem to make sense.

I made a PR that removes Content-Type when the body is an instance of FormData regardless if it’s containing a Blob #758. It will be released soon

[assaf]

Essentially they’re running server-side code in V8 as service workers. A service worker can listen and respond to HTTP requests as fetch events: https://developer.mozilla.org/en-US/docs/Web/API/FetchEvent

Service workers don’t have access to window, the global context is globalThis, which also exists in Node.

I get the same error using Masto from a Chrome extension, it runs code in the background like a service worker. But Chrome is fine with masto/fetch, I’m guessing the XHR issue is specific to Cloudflare so they throttle outbound requests.