feat(node): add PORT_HEADER env var for reverse proxies with non-standard ports

[aloisklink]

Add support for the PORT_HEADER environment variable to @sveltejs/adapter-node that can be used to read the original port of a request from a reverse proxy, which is needed if the reverse proxy is hosted on a non-standard port (e.g. not port 80 for http nor port 443 for https).

This port is normally added as part of a x-forwarded-port header, which is used by many reverse proxies, although it's not as popular as the more common x-forwarded-proto and x-forwarded-host headers.

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• Ideally, include a test that fails without this PR but passes with it.
  • It looks like tests for adapter-node have been broken and disabled since ecb423b, see

    kit/packages/adapter-node/package.json

    Line 29 in 336d8ae

    "test": "echo \"tests temporarily disabled\" # c8 uvu tests",

Tests

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  • pnpm test is failing for me on the master branch, but I don't think this is necessary, since adapter-node doesn't currently have any tests. I have linted and checked my changes.

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[Conduitry]

This seems like a reasonable addition. For the documentation, though, is there a more agnostic source we can link to about the X-Forwarded-Port header? If not, I'd probably rather just not link to anything than link to an AWS documentation page.

[aloisklink]

For the documentation, though, is there a more agnostic source we can link to about the X-Forwarded-Port header? If not, I'd probably rather just not link to anything than link to an AWS documentation page.

I've removed this link. Unfortunately, the only agnostic source I could find was https://dzone.com/articles/what-are-x-forwarded-headers-and-why-is-it-used, but it looks like that article might have been plagiarized from https://requestly.io/blog/what-are-x-forwarded-headers-and-why-it-is-used/, which is another product specific link.

Searching for "X-Forwarded-Port" on GitHub gives 44k matches, so it's clearly popular, but not popular enough to be on MDN!

I did find this blog post briefly mentioning it, but only in relation to the RFC 7239 Forwarded HTTP header, which makes it outdated (and I see you've already got #11148 open for adding support for it to SvelteKit, although I don't know how popular it is with reverse proxies).

[Rich-Harris]

thank you!