Improves initial cache registration by handling missing page data and prefetch data gracefully.

Author: AyronK

examples/redis-minimal/src/app/isr-example/blog/[id]/page.tsx

@@ -1,35 +1,33 @@
 interface Post {
-    id: string
-    title: string
-    content: string
-  }
-   
-  // Next.js will invalidate the cache when a
-  // request comes in, at most once every 60 seconds.
-  export const revalidate = 60
-   
-  export async function generateStaticParams() {
-    const posts: Post[] = await fetch('https://api.vercel.app/blog').then((res) =>
-      res.json()
-    )
-    return posts.map((post) => ({
-      id: String(post.id),
-    }))
-  }
-   
-  export default async function Page({
-    params,
-  }: {
-    params: Promise<{ id: string }>
-  }) {
-    const { id } = await params
-    const post: Post = await fetch(`https://api.vercel.app/blog/${id}`).then(
-      (res) => res.json()
-    )
-    return (
-      <main>
-        <h1>{post.title}</h1>
-        <p>{post.content}</p>
-      </main>
-    )
-  }
+  id: string;
+  title: string;
+  content: string;
+}
+
+export const revalidate = 3600;
+
+export async function generateStaticParams() {
+  const posts: Post[] = await fetch("https://api.vercel.app/blog").then((res) =>
+    res.json()
+  );
+  return posts.map((post) => ({
+    id: String(post.id),
+  }));
+}
+
+export default async function Page({
+  params,
+}: {
+  params: Promise<{ id: string }>;
+}) {
+  const { id } = await params;
+  const post: Post = await fetch(`https://api.vercel.app/blog/${id}`).then(
+    (res) => res.json()
+  );
+  return (
+    <main>
+      <h1>{post.title}</h1>
+      <p>{post.content}</p>
+    </main>
+  );
+}

examples/redis-minimal/src/pages/posts/[id].tsx

@@ -36,7 +36,7 @@ export const getStaticProps: GetStaticProps<PostPageProps> = async ({
     props: {
       post,
     },
-    revalidate: 60,
+    revalidate: 3600,
   };
 };
 

packages/nextjs-cache-handler/package-lock.json

@@ -18,7 +18,7 @@
     "next",
     "redis"
   ],
-  "version": "2.1.0-canary.11",
+  "version": "2.1.0-canary.12",
   "type": "module",
   "license": "MIT",
   "description": "Next.js cache handlers",

packages/nextjs-cache-handler/package.json

@@ -261,6 +261,15 @@ export async function registerInitialCache(
     let pageData: string | object | undefined;
     let meta: NextRouteMetadata | undefined;
     let rscData: string | undefined;
+
+    if (debug) {
+      console.info(
+        "[CacheHandler] [%s] %s",
+        "registerInitialCache",
+        "Reading file system cache",
+      );
+    }
+
     try {
       [html, pageData, rscData, meta] = await Promise.all([
         fsPromises.readFile(`${pathToRouteFiles}.html`, "utf-8"),
@@ -269,11 +278,31 @@ export async function registerInitialCache(
             `${pathToRouteFiles}.${isAppRouter ? "rsc" : "json"}`,
             "utf-8",
           )
-          .then((data) => (isAppRouter ? data : (JSON.parse(data) as object))),
+          .then((data) => (isAppRouter ? data : (JSON.parse(data) as object)))
+          .catch((error) => {
+            console.warn(
+              "[CacheHandler] [%s] %s %s",
+              "registerInitialCache",
+              "Failed to read page data, assuming it does not exist",
+              `Error: ${error}`,
+            );
+
+            return undefined;
+          }),
         isAppRouter
           ? fsPromises
               .readFile(`${pathToRouteFiles}.prefetch.rsc`, "utf-8")
               .then((data) => data)
+              .catch((error) => {
+                console.warn(
+                  "[CacheHandler] [%s] %s %s",
+                  "registerInitialCache",
+                  "Failed to read page prefetch data, assuming it does not exist",
+                  `Error: ${error}`,
+                );
+
+                return undefined;
+              })
           : undefined,
         isAppRouter
           ? fsPromises
@@ -294,9 +323,17 @@ export async function registerInitialCache(
       return;
     }
 
+    if (debug) {
+      console.info(
+        "[CacheHandler] [%s] %s",
+        "registerInitialCache",
+        "Saving file system cache to cache handler",
+      );
+    }
+
     try {
       const value: IncrementalCachedAppPageValue &
-        Pick<IncrementalCachedPageValue, "pageData"> = {
+        Partial<Pick<IncrementalCachedPageValue, "pageData">> = {
         kind: (isAppRouter ? "APP_PAGE" : "PAGES") as unknown as any,
         html,
         pageData,
@@ -305,13 +342,21 @@ export async function registerInitialCache(
         status: meta?.status,
         rscData:
           isAppRouter && rscData ? Buffer.from(rscData, "utf-8") : undefined,
-        segmentData: undefined,
+        segmentData: undefined, // TODO: Add segment data
       };
 
       await cacheHandler.set(cachePath, value, {
         revalidate,
         internal_lastModified: lastModified,
       });
+
+      if (debug) {
+        console.info(
+          "[CacheHandler] [%s] %s",
+          "registerInitialCache",
+          "Saved file system cache to cache handler",
+        );
+      }
     } catch (error) {
       if (debug) {
         console.warn(