fix: when revalidating, revalidate all previously visited pages (#1507)

packages/ui/docs-bundle/src/pages/api/fern-docs/revalidate-all/v3.ts

@@ -1,3 +1,4 @@
+import { DocsKVCache } from "@/server/DocsCache";
 import { Revalidator } from "@/server/revalidator";
 import { getXFernHostNode } from "@/server/xfernhost/node";
 import * as FernNavigation from "@fern-api/fdr-sdk/navigation";
@@ -62,11 +63,17 @@ const handler: NextApiHandler = async (
         const slugCollector = NodeCollector.collect(node);
         const slugs = slugCollector.getPageSlugs();
 
+        const cache = DocsKVCache.getInstance(xFernHost);
+        const previouslyVisitedSlugs = (await cache.getVisitedSlugs()).filter((slug) => !slugs.includes(slug));
+
         const results: FernDocs.RevalidationResult[] = [];
         for (const batch of chunk(slugs, DEFAULT_BATCH_SIZE)) {
             results.push(...(await revalidate.batch(batch)));
         }
 
+        // Revalidate previously visited slugs
+        await revalidate.batch(previouslyVisitedSlugs);
+
         const successfulRevalidations = results.filter(isSuccessResult);
         const failedRevalidations = results.filter(isFailureResult);
 

packages/ui/docs-bundle/src/pages/api/fern-docs/revalidate-all/v4.ts

@@ -1,3 +1,4 @@
+import { DocsKVCache } from "@/server/DocsCache";
 import { Revalidator } from "@/server/revalidator";
 import { getXFernHostNode } from "@/server/xfernhost/node";
 import * as FernNavigation from "@fern-api/fdr-sdk/navigation";
@@ -70,11 +71,20 @@ const handler: NextApiHandler = async (
 
     const node = FernNavigation.utils.convertLoadDocsForUrlResponse(docs.body);
     const slugs = NodeCollector.collect(node).getPageSlugs();
+    const revalidate = new Revalidator(res, xFernHost);
+
+    if (offset === 0) {
+        const cache = DocsKVCache.getInstance(xFernHost);
+        const previouslyVisitedSlugs = (await cache.getVisitedSlugs()).filter((slug) => !slugs.includes(slug));
+
+        // Revalidate previously visited slugs
+        await revalidate.batch(previouslyVisitedSlugs);
+    }
+
     const total = slugs.length;
     const start = offset * limit;
     const batch = slugs.slice(start, start + limit);
 
-    const revalidate = new Revalidator(res, xFernHost);
     const results = await revalidate.batch(batch);
 
     return res.status(200).json({ total, results });

packages/ui/docs-bundle/src/pages/static/[host]/[[...slug]].tsx

@@ -1,5 +1,7 @@
+import { DocsKVCache } from "@/server/DocsCache";
 import { getDocsPageProps } from "@/server/getDocsPageProps";
 import { withSSGProps } from "@/server/withSSGProps";
+import { FernNavigation } from "@fern-api/fdr-sdk";
 import { DocsPage } from "@fern-ui/ui";
 import { GetStaticPaths, GetStaticProps } from "next";
 import { ComponentProps } from "react";
@@ -11,7 +13,18 @@ export const getStaticProps: GetStaticProps<ComponentProps<typeof DocsPage>> = a
     const xFernHost = params.host as string;
     const slugArray = params.slug == null ? [] : Array.isArray(params.slug) ? params.slug : [params.slug];
 
-    return withSSGProps(getDocsPageProps(xFernHost, slugArray));
+    const props = await withSSGProps(getDocsPageProps(xFernHost, slugArray));
+
+    const cache = DocsKVCache.getInstance(xFernHost);
+    const slug = FernNavigation.utils.slugjoin(...slugArray);
+
+    if ("props" in props) {
+        cache.addVisitedSlugs(slug);
+    } else if ("notFound" in props || "redirect" in props) {
+        cache.removeVisitedSlugs(slug);
+    }
+
+    return props;
 };
 
 export const getStaticPaths: GetStaticPaths = () => {

packages/ui/docs-bundle/src/server/DocsCache.ts

@@ -0,0 +1,38 @@
+import type { FernNavigation } from "@fern-api/fdr-sdk";
+import { kv } from "@vercel/kv";
+
+const DEPLOYMENT_ID = process.env.VERCEL_DEPLOYMENT_ID ?? "development";
+const PREFIX = `docs:${DEPLOYMENT_ID}`;
+
+export class DocsKVCache {
+    private static instance: Map<string, DocsKVCache>;
+
+    private constructor(private domain: string) {}
+
+    public static getInstance(domain: string): DocsKVCache {
+        if (!DocsKVCache.instance) {
+            DocsKVCache.instance = new Map<string, DocsKVCache>();
+        }
+
+        const instance = DocsKVCache.instance.get(domain);
+        if (!instance) {
+            const newInstance = new DocsKVCache(domain);
+            DocsKVCache.instance.set(domain, newInstance);
+            return newInstance;
+        } else {
+            return instance;
+        }
+    }
+
+    public async addVisitedSlugs(...slug: FernNavigation.Slug[]): Promise<void> {
+        await kv.sadd(`${PREFIX}:${this.domain}:visited-slugs`, ...slug);
+    }
+
+    public async getVisitedSlugs(): Promise<FernNavigation.Slug[]> {
+        return kv.smembers(`${PREFIX}:${this.domain}:visited-slugs`);
+    }
+
+    public async removeVisitedSlugs(...slug: FernNavigation.Slug[]): Promise<void> {
+        await kv.srem(`${PREFIX}:${this.domain}:visited-slugs`, ...slug);
+    }
+}