fix: populate static api routes for our staticRouteMatcher

Author: sommeeeer

packages/open-next/src/adapters/config/index.ts

@@ -1,5 +1,6 @@
 import path from "node:path";
 
+import type { RouteDefinition } from "types/next-types";
 import { debug } from "../logger";
 import {
   loadAppPathRoutesManifest,
@@ -11,6 +12,7 @@ import {
   loadFunctionsConfigManifest,
   loadHtmlPages,
   loadMiddlewareManifest,
+  loadPagesManifest,
   loadPrerenderManifest,
   loadRoutesManifest,
 } from "./util.js";
@@ -39,3 +41,38 @@ export const AppPathRoutesManifest =
 
 export const FunctionsConfigManifest =
   /* @__PURE__ */ loadFunctionsConfigManifest(NEXT_DIR);
+
+/**
+ * Returns static API routes for both app and pages router cause Next will filter them out in staticRoutes in `routes-manifest.json`.
+ * We also need to filter out page files that are under `app/api/*` as those would not be present in the routes manifest either.
+ * This line from Next.js skips it:
+ * https://github.com/vercel/next.js/blob/ded56f952154a40dcfe53bdb38c73174e9eca9e5/packages/next/src/build/index.ts#L1299
+ *
+ * Without it handleFallbackFalse will 404 on static API routes if there is a catch-all route on root level.
+ */
+export function getStaticAPIRoutes(): RouteDefinition[] {
+  const createRouteDefinition = (route: string) => ({
+    page: route,
+    regex: `^${route}(?:/)?$`,
+  });
+  const dynamicRoutePages = new Set(
+    RoutesManifest.routes.dynamic.map(({ page }) => page),
+  );
+  const PagesManifest = loadPagesManifest(NEXT_DIR);
+  const pagesStaticAPIRoutes = Object.keys(PagesManifest)
+    .filter(
+      (route) => route.startsWith("/api/") && !dynamicRoutePages.has(route),
+    )
+    .map(createRouteDefinition);
+
+  // We filter out both static API and page routes from the app paths manifest
+  const appPathsStaticAPIRoutes = Object.values(AppPathRoutesManifest)
+    .filter(
+      (route) =>
+        route.startsWith("/api/") ||
+        (route === "/api" && !dynamicRoutePages.has(route)),
+    )
+    .map(createRouteDefinition);
+
+  return [...pagesStaticAPIRoutes, ...appPathsStaticAPIRoutes];
+}

packages/open-next/src/adapters/config/util.ts

@@ -24,7 +24,7 @@ export function loadBuildId(nextDir: string) {
 export function loadPagesManifest(nextDir: string) {
   const filePath = path.join(nextDir, "server/pages-manifest.json");
   const json = fs.readFileSync(filePath, "utf-8");
-  return JSON.parse(json);
+  return JSON.parse(json) as Record<string, string>;
 }
 
 export function loadHtmlPages(nextDir: string) {

packages/open-next/src/core/routing/matcher.ts

@@ -437,7 +437,12 @@ export function handleFallbackFalse(
     ? rawPath
     : `/${NextConfig.i18n?.defaultLocale}${rawPath}`;
   // We need to remove the trailing slash if it exists
-  if (NextConfig.trailingSlash && localizedPath.endsWith("/")) {
+  // Not if localizedPath is "/" tho, because that would not make it find `isPregenerated` below since it would be try to match an empty string.
+  if (
+    localizedPath !== "/" &&
+    NextConfig.trailingSlash &&
+    localizedPath.endsWith("/")
+  ) {
     localizedPath = localizedPath.slice(0, -1);
   }
   const matchedStaticRoute = staticRouteMatcher(localizedPath);
@@ -447,6 +452,7 @@ export function handleFallbackFalse(
   const matchedDynamicRoute = dynamicRouteMatcher(localizedPath).filter(
     ({ route }) => !prerenderedFallbackRoutesName.includes(route),
   );
+
   const isPregenerated = Object.keys(routes).includes(localizedPath);
   if (
     routeFallback &&

packages/open-next/src/core/routing/routeMatcher.ts

@@ -1,4 +1,8 @@
-import { AppPathRoutesManifest, RoutesManifest } from "config/index";
+import {
+  AppPathRoutesManifest,
+  RoutesManifest,
+  getStaticAPIRoutes,
+} from "config/index";
 import type { RouteDefinition } from "types/next-types";
 import type { ResolvedRoute, RouteType } from "types/open-next";
 
@@ -53,5 +57,8 @@ function routeMatcher(routeDefinitions: RouteDefinition[]) {
   };
 }
 
-export const staticRouteMatcher = routeMatcher(RoutesManifest.routes.static);
+export const staticRouteMatcher = routeMatcher([
+  ...RoutesManifest.routes.static,
+  ...getStaticAPIRoutes(),
+]);
 export const dynamicRouteMatcher = routeMatcher(RoutesManifest.routes.dynamic);

packages/open-next/src/core/routingHandler.ts

@@ -24,7 +24,6 @@ import {
 } from "./routing/matcher";
 import { handleMiddleware } from "./routing/middleware";
 import {
-  apiPrefix,
   dynamicRouteMatcher,
   staticRouteMatcher,
 } from "./routing/routeMatcher";
@@ -158,13 +157,6 @@ export default async function routingHandler(
       isExternalRewrite = fallbackRewrites.isExternalRewrite;
     }
 
-    // Api routes are not present in the routes manifest except if they're not behind /api
-    // /api even if it's a page route doesn't get generated in the manifest
-    // Ideally we would need to properly check api routes here
-    const isApiRoute =
-      internalEvent.rawPath === apiPrefix ||
-      internalEvent.rawPath.startsWith(`${apiPrefix}/`);
-
     const isNextImageRoute = internalEvent.rawPath.startsWith("/_next/image");
 
     const isRouteFoundBeforeAllRewrites =
@@ -175,7 +167,6 @@ export default async function routingHandler(
     if (
       !(
         isRouteFoundBeforeAllRewrites ||
-        isApiRoute ||
         isNextImageRoute ||
         // We need to check again once all rewrites have been applied
         staticRouteMatcher(internalEvent.rawPath).length > 0 ||