do not require schema version on manifest handler

Author: lkostrowski

.changeset/silent-walls-heal.md

@@ -39,7 +39,7 @@ describe("ManifestActionHandler", () => {
     expect(manifestFactory).toHaveBeenCalledWith({
       appBaseUrl: "http://example.com",
       request: {},
-      schemaVersion: 3.20,
+      schemaVersion: 3.2,
     });
   });
 
@@ -64,18 +64,21 @@ describe("ManifestActionHandler", () => {
     expect(result.status).toBe(405);
     expect(result.body).toBe("Method not allowed");
     expect(manifestFactory).not.toHaveBeenCalled();
-  })
+  });
 
-  it("should return 400 when receives null schema version header from unsupported legacy Saleor version", async () => {
+  /**
+   * api/manifest endpoint is GET and header should be optional. It can be used to install the app eventually,
+   * but also to preview the manifest from the plain GET request
+   */
+  it("should NOT return 400 when receives null schema version header from unsupported legacy Saleor version", async () => {
     adapter.getHeader = vi.fn().mockReturnValue(null);
     const handler = new ManifestActionHandler(adapter);
 
     const manifestFactory = vi.fn().mockResolvedValue(mockManifest);
 
     const result = await handler.handleAction({ manifestFactory });
 
-    expect(result.status).toBe(400);
-    expect(result.body).toBe("Missing schema version header");
-    expect(manifestFactory).not.toHaveBeenCalled();
+    expect(result.status).toBe(200);
+    expect(manifestFactory).toHaveBeenCalled();
   });
 });

src/handlers/actions/manifest-action-handler.test.ts

@@ -14,8 +14,12 @@ export type CreateManifestHandlerOptions<T> = {
   manifestFactory(context: {
     appBaseUrl: string;
     request: T;
-    /** Added in Saleor 3.15 */
-    schemaVersion: number;
+    /**
+     * Schema version is optional. During installation, Saleor will send it,
+     * so manifest can be generated according to the version. But it may
+     * be also requested from plain GET from the browser, so it may not be available
+     */
+    schemaVersion?: number;
   }): AppManifest | Promise<AppManifest>;
 };
 
@@ -36,14 +40,6 @@ export class ManifestActionHandler<I> implements ActionHandlerInterface {
       return invalidMethodResponse;
     }
 
-    if (!schemaVersion) {
-      return {
-        status: 400,
-        bodyType: "string",
-        body: "Missing schema version header",
-      };
-    }
-
     try {
       const manifest = await options.manifestFactory({
         appBaseUrl: baseURL,