fix dataRoutes omitting basePath

.changeset/happy-pandas-hope.md

@@ -0,0 +1,6 @@
+---
+"@opennextjs/aws": patch
+"tests-unit": patch
+---
+
+fix dataRoutes omitting basePath in page router (#897)

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

@@ -381,8 +381,8 @@ export function fixDataPage(
   buildId: string,
 ): InternalEvent | InternalResult {
   const { rawPath, query } = internalEvent;
-  const dataPattern = `${NextConfig.basePath ?? ""}/_next/data/${buildId}`;
-
+  const basePath = NextConfig.basePath ?? "";
+  const dataPattern = `${basePath}/_next/data/${buildId}`;
   // Return 404 for data requests that don't match the buildId
   if (rawPath.startsWith("/_next/data") && !rawPath.startsWith(dataPattern)) {
     return {
@@ -397,9 +397,9 @@ export function fixDataPage(
   }
 
   if (rawPath.startsWith(dataPattern) && rawPath.endsWith(".json")) {
-    const newPath = rawPath
+    const newPath = `${basePath}${rawPath
       .slice(dataPattern.length, -".json".length)
-      .replace(/^\/index$/, "/");
+      .replace(/^\/index$/, "/")}`;
     query.__nextDataReq = "1";
 
     return {

packages/tests-unit/tests/core/routing/matcher.test.ts

@@ -598,18 +598,19 @@ describe("fixDataPage", () => {
   });
 
   it("should remove json extension from data requests (with base path) and add __nextDataReq to query", () => {
-    NextConfig.basePath = "/base";
+    const mockBasePath = "/base";
+    NextConfig.basePath = mockBasePath;
 
     const event = createEvent({
-      url: "https://on/base/_next/data/abc/test/file.json?hello=world",
+      url: `https://on${mockBasePath}/_next/data/abc/test/file.json?hello=world`,
     });
 
     const response = fixDataPage(event, "abc");
 
     expect(response).toEqual({
       ...event,
-      rawPath: "/test/file",
-      url: "https://on/test/file?hello=world&__nextDataReq=1",
+      rawPath: `${mockBasePath}/test/file`,
+      url: `https://on${mockBasePath}/test/file?hello=world&__nextDataReq=1`,
     });
 
     NextConfig.basePath = undefined;