Account for 'x-forwarded-proto' and 'x-forwarded-port'

[zhawtof]

Problem

Slack does not allow for http callbacks. However, it seems that when using a tunneled route (using VSCode ports personally), that the auth server is ignoring the forwarded protocol and the forwarded port.

Relevant Code

openauth/packages/openauth/src/util.ts

Lines 7 to 11 in 70233c7

	export function getRelativeUrl(ctx: Context, path: string) {
	const result = new URL(path, ctx.req.url)
	result.host = ctx.req.header("x-forwarded-host") || result.host
	return result.toString()
	}

Necessary Changes

• Account for x-forwarded-proto and x-forwarded-port