From bce56fd9bec81253a2bae4f72ef4392a7eb6f010 Mon Sep 17 00:00:00 2001
From: Mathias Oterhals Myklebust <mom@variant.no>
Date: Mon, 23 Sep 2024 11:04:02 +0200
Subject: [PATCH] refactor(app): extract sitemap base url parsing into common
 utility function

---
 src/app/env.ts     | 12 ++++++++++++
 src/app/robots.ts  | 15 +++++++++++++--
 src/app/sitemap.ts | 13 ++++++-------
 src/middleware.ts  | 31 +++++++++++++++++++------------
 4 files changed, 50 insertions(+), 21 deletions(-)
 create mode 100644 src/app/env.ts

diff --git a/src/app/env.ts b/src/app/env.ts
new file mode 100644
index 000000000..15f0036c8
--- /dev/null
+++ b/src/app/env.ts
@@ -0,0 +1,12 @@
+import { Result, ResultError, ResultOk } from "studio/utils/result";
+
+export function readBaseUrl(): Result<URL, string> {
+  const url = process.env.NEXT_PUBLIC_URL;
+  if (url === undefined) {
+    return ResultError("Missing environment variable: NEXT_PUBLIC_URL");
+  }
+  if (!URL.canParse(url)) {
+    return ResultError("Invalid environment variable: NEXT_PUBLIC_URL");
+  }
+  return ResultOk(new URL(url));
+}
diff --git a/src/app/robots.ts b/src/app/robots.ts
index 3265d2247..fece8039f 100644
--- a/src/app/robots.ts
+++ b/src/app/robots.ts
@@ -1,11 +1,22 @@
 import type { MetadataRoute } from "next";
 
+import { readBaseUrl } from "./env";
+
 export default function robots(): MetadataRoute.Robots {
-  return {
+  const robotsFile: MetadataRoute.Robots = {
     rules: {
       userAgent: "*",
       disallow: ["/studio", "/shared", "/api"],
     },
-    sitemap: new URL("sitemap.xml", process.env.NEXT_PUBLIC_URL).toString(),
   };
+  const baseUrlResult = readBaseUrl();
+  if (baseUrlResult.ok) {
+    robotsFile.sitemap = new URL("sitemap.xml", baseUrlResult.value).toString();
+  } else {
+    console.warn(
+      "Could not include sitemap in robots.txt, missing base url:",
+      baseUrlResult.error,
+    );
+  }
+  return robotsFile;
 }
diff --git a/src/app/sitemap.ts b/src/app/sitemap.ts
index 274a90660..8528b95f7 100644
--- a/src/app/sitemap.ts
+++ b/src/app/sitemap.ts
@@ -7,21 +7,20 @@ import { DOCUMENTS_WITH_SLUG_QUERY } from "studio/lib/queries/document";
 import { LANDING_PAGE_QUERY } from "studio/lib/queries/navigation";
 import { token } from "studio/lib/token";
 
+import { readBaseUrl } from "./env";
+
 const clientWithToken = client.withConfig({ token });
 
 export const dynamic = "force-dynamic";
 export const fetchCache = "default-no-store";
 
 export default async function sitemap(): Promise<MetadataRoute.Sitemap> {
-  const baseUrl =
-    process.env.NEXT_PUBLIC_URL !== undefined &&
-    URL.canParse(process.env.NEXT_PUBLIC_URL)
-      ? new URL(process.env.NEXT_PUBLIC_URL)
-      : undefined;
-  if (baseUrl === undefined) {
-    console.error("Failed to generate sitemap, missing baseUrl");
+  const baseUrlResult = readBaseUrl();
+  if (!baseUrlResult.ok) {
+    console.error("Failed to generate sitemap:", baseUrlResult.error);
     return [];
   }
+  const baseUrl = baseUrlResult.value;
   const slugDocuments = await clientWithToken.fetch<DocumentWithSlug[]>(
     DOCUMENTS_WITH_SLUG_QUERY,
   );
diff --git a/src/middleware.ts b/src/middleware.ts
index d77ee7226..f639dc33c 100644
--- a/src/middleware.ts
+++ b/src/middleware.ts
@@ -3,28 +3,35 @@ import { NextRequest, NextResponse } from "next/server";
 import { RedirectDestinationSlugPage } from "studio/lib/interfaces/redirect";
 import { REDIRECT_BY_SOURCE_SLUG_QUERY } from "studio/lib/queries/redirects";
 
+import { readBaseUrl } from "./app/env";
 import { HTTP_STATUSES } from "./utils/http";
 
 export async function middleware(request: NextRequest) {
+  const baseUrlResult = readBaseUrl();
+  if (!baseUrlResult.ok) {
+    console.error(
+      "Failed to run middleware, missing base url:",
+      baseUrlResult.error,
+    );
+    return;
+  }
+  const baseUrl = baseUrlResult.value;
   const slug = request.nextUrl.pathname;
   const slugQueryParam = slug.replace(/^\/+/, "");
   /*
    fetching redirect data via API route to avoid token leaking to client
    (middleware should run on server, but `experimental_taintUniqueValue` begs to differ...)
   */
-  const redirectRes = await fetch(
-    new URL("/api/fetchData", process.env.NEXT_PUBLIC_URL),
-    {
-      method: "POST",
-      headers: {
-        "Content-Type": "application/json",
-      },
-      body: JSON.stringify({
-        query: REDIRECT_BY_SOURCE_SLUG_QUERY,
-        params: { slug: slugQueryParam },
-      }),
+  const redirectRes = await fetch(new URL("/api/fetchData", baseUrl), {
+    method: "POST",
+    headers: {
+      "Content-Type": "application/json",
     },
-  );
+    body: JSON.stringify({
+      query: REDIRECT_BY_SOURCE_SLUG_QUERY,
+      params: { slug: slugQueryParam },
+    }),
+  });
   if (redirectRes.ok) {
     const redirect: RedirectDestinationSlugPage | null =
       await redirectRes.json();