fix: set no-op proxy config to get Vite HTTPS working

[eltigerchino]

closes #11365

cc: @Conduitry @benmccann

This PR gets the Vite HTTPS working again by filtering out two types of keys from the incoming request headers object before we pass it to a new Request object. Doing so prevents the two errors we currently encounter as shown below.

1. When there's a symbol key in the request headers:

TypeError: Request constructor: init.headers is a symbol, which cannot be converted to a DOMString.
    at webidl.errors.exception (node:internal/deps/undici/undici:3384:14)
    at webidl.converters.DOMString (node:internal/deps/undici/undici:3650:29)
    at webidl.converters.ByteString (node:internal/deps/undici/undici:3658:35)
    at Object.record<ByteString, ByteString> (node:internal/deps/undici/undici:3567:30)
    at webidl.converters.HeadersInit (node:internal/deps/undici/undici:8715:67)
    at Object.RequestInit (node:internal/deps/undici/undici:3624:21)
    at new Request (node:internal/deps/undici/undici:9267:34)
    at getRequest (file:///home/chewteeming/my-app/node_modules/.pnpm/@[email protected]_@[email protected][email protected][email protected][email protected][email protected]/node_modules/@sveltejs/kit/src/exports/node/index.js:122:9)
    at file:///home/chewteeming/my-app/node_modules/.pnpm/@[email protected]_@[email protected][email protected][email protected][email protected][email protected]/node_modules/@sveltejs/kit/src/exports/vite/dev/index.js:497:27
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)

2. When there's HTTP/2 pseudo-headers in the request headers (partially reimplements https://github.com/sveltejs/kit/pull/3572/files):

TypeError: Headers.append: ":method" is an invalid header name.
    at webidl.errors.exception (node:internal/deps/undici/undici:3384:14)
    at webidl.errors.invalidArgument (node:internal/deps/undici/undici:3395:28)
    at appendHeader (node:internal/deps/undici/undici:8339:29)
    at fill (node:internal/deps/undici/undici:8325:11)
    at new Request (node:internal/deps/undici/undici:9490:13)
    at getRequest (file:///home/chewteeming/my-app/node_modules/.pnpm/@[email protected]_@[email protected][email protected][email protected][email protected][email protected]/node_modules/@sveltejs/kit/src/exports/node/index.js:118:9)
    at file:///home/chewteeming/my-app/node_modules/.pnpm/@[email protected]_@[email protected][email protected][email protected][email protected][email protected]/node_modules/@sveltejs/kit/src/exports/vite/dev/index.js:497:27

Open to suggestions for a better way to do this.

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[Conduitry]

Since Vite is involved, this is a dev-only issue, right?

The issue we ran into before IIRC is that node-fetch didn't like these headers. That became unnecessary when we switched to Undici.

The function you're modifying in this PR is the main function to generate the Request object in production for various adapters for Node-based systems. This won't immediately make more work in production for apps using them (since the released version of the adapters bundle this code), but eventually it will.

Without looking much at what would be involved with this, my sense is that we should focus on the dev-time code, which would mean adjusting how getRequest is called at

kit/packages/kit/src/exports/vite/dev/index.js

Line 497 in 8ec471c

const request = await getRequest({

rather than adjusting the getRequest implementation.

We may then also need to do something for preview-time. But we shouldn't be doing this extra work to normalize requests in prod builds if it's not necessary.

[eltigerchino]

Turns out the better alternative was to set the no-op proxy config as implemented previously and is the current workaround. This also fixes another issue with the request URL being set incorrectly that the previous implementation had.

I'm not sure if the config overriding is in the right place, but it doesn't seem to work if done too late such as immediately before configuring the dev and preview server.

[Rich-Harris]

preview: https://svelte-dev-git-preview-kit-12907-svelte.vercel.app/

this is an automated message

[benmccann]

Awesome to close such a frequently encountered issue! Thanks!!