Makes Node adapter respect HOST (#1365)

[tsanth]

By default, the HOST variable is set to 127.0.0.1, for safety.

I lack the experience to set up a test runnable via pnpm test, but I've tested this as follows:

• I add in my PR.
• npm run build
• HOST=192.168.1.64 npm start
• Verify that I can reach my server only from its IPv4 address
• Back out my PR
• npm run build
• HOST=192.168.1.64 npm start
• Verify that I can reach my server from all of 1) localhost, 2) IPv4, and 3) IPv6

Before submitting the PR, please make sure you do the following

• It's really useful if your PR references an issue where it is discussed ahead of time. In many cases, features are absent for a reason. For large changes, please create an RFC: https://github.com/sveltejs/rfcs
• This message body should clearly illustrate what problems it solves.
• Ideally, include a test that fails without this PR but passes with it.

Tests

• Run the tests with pnpm test and lint the project with pnpm lint

Changesets

• If your PR makes a change that should be noted in one or more packages' changelogs, generate a changeset by running pnpx changeset and following the prompts

[Rich-Harris]

Thank you — is there a reason to default to 127.0.0.1? Given that this is intended for production servers, surely we want the address to be unspecified?

[tsanth]

My typical workflow is to use a local nginx instance to reverse proxy requests to Node (to simplify SSL setup, among things), so I set the default assuming that use case.

Since this is for production servers, I've modifed the default to be 0.0.0.0 instead, so as to capture all interfaces.

[Rich-Harris]

Thank you — I took the liberty of adding a changeset and docs

[Conduitry]

Is this TODO still a TODO? Would the env vars take precedence?

[Rich-Harris]

it's still a TODO insofar as you can't specify a default port/host via the adapter config. Is that something worth having, if we have environment variables?

[Conduitry]

Well yeah what I meant is: is this something we still want to do? I don't have especially strong opinions about that. I assume it would be additional args you pass to the adapter factory function and not somewhere else in the config.

[Rich-Harris]

it would be, yeah. tbh i'm inclined to just remove the TODO comment — it's less confusing if there's only one way to set non-default values, and we need environment variables regardless so that it's configurable at runtime