feat: improve handling of deployment env vars

These are now defined in Netlify UI for dedicated environments (test, stage, production):

AUTH_URL
NEXTAUTH_URL
PUBLIC_URL

Code now falls back to incoming request host. Mainly used for
deployment previews which do not have Akamai in front, meaning
we do not need the above workaround as incoming request host
matches the actual public facing host. When Akamai is in front,
we lose the public facing host in Netlify's routing layer as they
internally use `x-forwarded-for` and we can't claim it for our usage.

middlewares/authRequired.ts

@@ -2,8 +2,7 @@ import { NextResponse } from "next/server"
 
 import { authRequired, mfaRequired } from "@/constants/routes/authRequired"
 import { login } from "@/constants/routes/handleAuth"
-import { env } from "@/env/server"
-import { internalServerError } from "@/server/errors/next"
+import { getPublicNextURL } from "@/server/utils"
 
 import { auth } from "@/auth"
 import { findLang } from "@/utils/languages"
@@ -44,14 +43,7 @@ export const middleware = auth(async (request) => {
   const isLoggedIn = !!request.auth
   const hasError = request.auth?.error
 
-  if (!env.PUBLIC_URL) {
-    throw internalServerError("Missing value for env.PUBLIC_URL")
-  }
-
-  const publicUrl = new URL(env.PUBLIC_URL)
-  const nextUrlPublic = nextUrl.clone()
-  nextUrlPublic.host = publicUrl.host
-  nextUrlPublic.hostname = publicUrl.hostname
+  const nextUrlPublic = getPublicNextURL(request)
 
   /**
    * Function to validate MFA from token data

middlewares/currentWebLogout.ts

@@ -2,6 +2,7 @@ import { NextResponse } from "next/server"
 
 import { env } from "@/env/server"
 import { badRequest, internalServerError } from "@/server/errors/next"
+import { getPublicURL } from "@/server/utils"
 
 import { findLang } from "@/utils/languages"
 
@@ -16,10 +17,7 @@ export const middleware: NextMiddleware = (request) => {
   }
   const lang = findLang(request.nextUrl.pathname)!
 
-  if (!env.PUBLIC_URL) {
-    throw internalServerError("No value for env.PUBLIC_URL")
-  }
-  const redirectTo = env.PUBLIC_URL
+  const redirectTo = getPublicURL(request)
 
   const headers = new Headers(request.headers)
   headers.set("x-returnurl", redirectTo)

middlewares/myPages.ts

@@ -8,6 +8,7 @@ import {
 } from "@/constants/routes/myPages"
 import { env } from "@/env/server"
 import { internalServerError, notFound } from "@/server/errors/next"
+import { getPublicNextURL } from "@/server/utils"
 
 import { findLang } from "@/utils/languages"
 
@@ -23,17 +24,9 @@ export const middleware: NextMiddleware = async (request) => {
 
   const myPagesRoot = myPages[lang]
   if (nextUrl.pathname === myPagesRoot) {
-    if (!env.PUBLIC_URL) {
-      throw internalServerError("Missing value for env.PUBLIC_URL")
-    }
-
-    const publicUrl = new URL(env.PUBLIC_URL)
-    const nextUrlClone = nextUrl.clone()
-    nextUrlClone.host = publicUrl.host
-    nextUrlClone.hostname = publicUrl.hostname
-
+    const nextUrlPublic = getPublicNextURL(request)
     const overviewUrl = overview[lang]
-    const redirectUrl = new URL(overviewUrl, nextUrlClone)
+    const redirectUrl = new URL(overviewUrl, nextUrlPublic)
     console.log(`[myPages] redirecting to: ${redirectUrl}`)
     return NextResponse.redirect(redirectUrl)
   }

middlewares/utils.ts

@@ -1,7 +1,5 @@
-import { stringify } from "querystring"
-
 import { Lang } from "@/constants/languages"
-import { env } from "@/env/server"
+import { getPublicNextURL } from "@/server/utils"
 
 import { resolve as resolveEntry } from "@/utils/entry"
 import { findLang } from "@/utils/languages"
@@ -11,18 +9,7 @@ import type { NextRequest } from "next/server"
 
 export function getDefaultRequestHeaders(request: NextRequest) {
   const lang = findLang(request.nextUrl.pathname)!
-
-  let nextUrl
-  if (env.PUBLIC_URL) {
-    const publicUrl = new URL(env.PUBLIC_URL)
-    const nextUrlPublic = request.nextUrl.clone()
-    nextUrlPublic.host = publicUrl.host
-    nextUrlPublic.hostname = publicUrl.hostname
-    nextUrl = nextUrlPublic
-  } else {
-    nextUrl = request.nextUrl
-  }
-
+  const nextUrlPublic = getPublicNextURL(request)
   const headers = new Headers(request.headers)
   headers.set("x-lang", lang)
   headers.set(
@@ -31,7 +18,7 @@ export function getDefaultRequestHeaders(request: NextRequest) {
       request.nextUrl.pathname.replace(`/${lang}`, "").replace(`/webview`, "")
     )
   )
-  headers.set("x-url", removeTrailingSlash(nextUrl.href))
+  headers.set("x-url", removeTrailingSlash(nextUrlPublic.href))
 
   return headers
 }