fix(ES-679): remove zero-valued Content-Length

.changeset/yellow-ladybugs-add.md

@@ -0,0 +1,5 @@
+---
+"@vue-storefront/sdk": patch
+---
+
+**[FIXED]** `Content-Length` header will no longer be appended to requests if its value is "0" - such situation caused Next.js server to crash

packages/sdk/src/__tests__/integration/modules/middlewareModule.spec.ts

@@ -252,6 +252,67 @@ describe("middlewareModule", () => {
     );
   });
 
+  it("should remove zero-valued Content-Length header as it would crash Next.js server", async () => {
+    const customHttpClient = jest.fn();
+    const sdkConfig = {
+      commerce: buildModule(middlewareModule<Endpoints>, {
+        apiUrl: "http://localhost:8181/commerce",
+        cdnCacheBustingId: "commit-hash",
+        httpClient: customHttpClient,
+        defaultRequestConfig: {
+          headers: {
+            "Content-Length": "0",
+          },
+        },
+      }),
+    };
+    const sdk = initSDK(sdkConfig);
+
+    await sdk.commerce.getProduct({ id: 1 });
+
+    expect(customHttpClient).toHaveBeenCalledWith(
+      "http://localhost:8181/commerce/getProduct",
+      expect.any(Array),
+      expect.objectContaining({
+        headers: {
+          "Content-Type": "application/json",
+          Accept: "application/json",
+        },
+      })
+    );
+  });
+
+  it("should pass non-zero-valued Content-Length header", async () => {
+    const customHttpClient = jest.fn();
+    const sdkConfig = {
+      commerce: buildModule(middlewareModule<Endpoints>, {
+        apiUrl: "http://localhost:8181/commerce",
+        cdnCacheBustingId: "commit-hash",
+        httpClient: customHttpClient,
+        defaultRequestConfig: {
+          headers: {
+            "Content-Length": "1000",
+          },
+        },
+      }),
+    };
+    const sdk = initSDK(sdkConfig);
+
+    await sdk.commerce.getProduct({ id: 1 });
+
+    expect(customHttpClient).toHaveBeenCalledWith(
+      "http://localhost:8181/commerce/getProduct",
+      expect.any(Array),
+      expect.objectContaining({
+        headers: {
+          "Content-Type": "application/json",
+          Accept: "application/json",
+          "Content-Length": "1000",
+        },
+      })
+    );
+  });
+
   it("should use different base URL during SSR if defined", async () => {
     const customHttpClient = jest.fn();
     const sdkConfig = {

packages/sdk/src/modules/middlewareModule/utils/getRequestSender.ts

@@ -68,11 +68,21 @@ export const getRequestSender = (options: Options): RequestSender => {
       Accept: "application/json",
       ...defaultRequestConfig.headers,
     };
-    const mergedHeaders = {
-      ...defaultHeaders,
-      ...methodHeaders,
-      ...headers,
-    };
+    const mergedHeaders = Object.fromEntries(
+      Object.entries({
+        ...defaultHeaders,
+        ...methodHeaders,
+        ...headers,
+      }).reduce<[string, string | string[]][]>(
+        (headersSoFar, [key, value]) =>
+          // Removing Content-Lenght header if it equals 0 because it would crash Next.js server
+          // eslint-disable-next-line eqeqeq
+          key.toLocaleLowerCase() === "content-length" && value == "0"
+            ? headersSoFar
+            : [...headersSoFar, [key, value]],
+        []
+      )
+    );
 
     const computedHeaders: ComputedConfig["headers"] = {};
     Object.entries(mergedHeaders).forEach(([key, value]) => {