Add middleware for grapher redirects

functions/grapher/_middleware.ts

@@ -0,0 +1,10 @@
+import { Env } from "../_common/env.js"
+import { getRedirectForUrl } from "../_common/redirectTools.js"
+
+export const onRequest: PagesFunction<Env> = async (context) => {
+    const url = new URL(context.request.url)
+    console.log("Looking up redirect for", url.pathname)
+    const redirect = await getRedirectForUrl(context.env, url)
+    if (redirect) return redirect
+    return await context.next()
+}