Add middleware

Author: oBusk

src/middleware.ts

@@ -0,0 +1,51 @@
+import { NextRequest, NextResponse } from "next/server";
+import type { Destination } from "./lib/destination";
+import specsToDiff from "./lib/utils/specsToDiff";
+import splitParts from "./lib/utils/splitParts";
+
+enum STATUS_CODES {
+    TEMPORARY_REDIRECT = 307,
+    PERMANENT_REDIRECT = 308,
+}
+
+export const config = {
+    matcher: "/((?!(?:about|api|_next|diff)(?:/.*)?|favicon.ico|icon.png).+)",
+};
+
+export async function middleware(request: NextRequest) {
+    console.log("[middleware]", request.nextUrl.pathname);
+
+    const parts = request.nextUrl.pathname.split("/")[1];
+
+    const specsOrVersions = splitParts(parts);
+
+    const url = new URL(`/api/-/destination`, request.url);
+    specsOrVersions.forEach((spec) => url.searchParams.append("specs", spec));
+
+    console.log("[middleware] fetching", url.toString());
+
+    const { redirect: red, canonicalSpecs }: Destination = await fetch(
+        url.toString(),
+    ).then((res) => res.json());
+
+    if (red) {
+        console.log("[middleware] redirecting to", red);
+        return NextResponse.redirect(
+            new URL(`/${specsToDiff(canonicalSpecs)}`, request.nextUrl),
+            red === "permanent"
+                ? STATUS_CODES.PERMANENT_REDIRECT
+                : STATUS_CODES.TEMPORARY_REDIRECT,
+        );
+    } else {
+        const url = new URL(
+            `/diff/${encodeURIComponent(
+                canonicalSpecs[0],
+            )}/${encodeURIComponent(canonicalSpecs[1])}`,
+            request.url,
+        );
+        console.log("[middleware] rewriting", url.toString());
+        return NextResponse.rewrite(url.toString());
+    }
+
+    return NextResponse.next();
+}