feat: add response header ignoring

src/index.js

@@ -15,6 +15,9 @@ module.exports = function (req, res, logFacilities, config, next) {
   const cacheVaryHeadersConfigured = config.cacheVaryHeaders
     ? config.cacheVaryHeaders
     : [];
+  const cacheIgnoreHeadersConfigured = config.cacheIgnoreHeaders
+    ? config.cacheIgnoreHeaders
+    : [];
   const maximumCachedResponseSize = config.maximumCachedResponseSize
     ? config.maximumCachedResponseSize
     : null;
@@ -174,6 +177,12 @@ module.exports = function (req, res, logFacilities, config, next) {
             .join("\n");
 
         varyCache.set(cacheKey, processedVary);
+
+        // Ignore headers
+        cacheIgnoreHeadersConfigured.forEach((header) => {
+          delete writtenHeaders[header.toLowerCase()];
+        });
+
         cache.set(cacheKeyWithVary, {
           body: responseBody,
           headers: writtenHeaders,
@@ -259,6 +268,9 @@ module.exports.configValidators = {
   cacheVaryHeaders: (value) =>
     Array.isArray(value) &&
     value.every((element) => typeof element === "string"),
+  cacheIgnoreHeaders: (value) =>
+    Array.isArray(value) &&
+    value.every((element) => typeof element === "string"),
   maximumCachedResponseSize: (value) =>
     typeof value === "number" || value === null
 };

tests/index.test.js

@@ -40,6 +40,7 @@ describe("SVR.JS Cache mod", () => {
 
     config = {
       cacheVaryHeaders: ["accept"],
+      cacheIgnoreHeaders: [],
       maximumCachedResponseSize: 1024
     };
 
@@ -120,15 +121,76 @@ describe("SVR.JS Cache mod", () => {
     expect(next).not.toHaveBeenCalled(); // No middleware should be called
   });
 
+  test("should cache the response and serve it on subsequent requests, while ignoring some headers", () => {
+    req.headers.host = "ignore.test.com";
+    req.headers.accept = "application/json";
+
+    // Headers to ignore
+    config.cacheIgnoreHeaders = ["x-header-ignored"];
+
+    parseCacheControl.mockReturnValue({});
+    parseVary.mockReturnValue(["accept"]);
+    shouldCacheResponse.mockReturnValue(true);
+
+    // Mock cache-control headers
+    res.getHeaders.mockReturnValue({ "cache-control": "max-age=300" });
+
+    // First request: cache the response
+    mod(req, res, logFacilities, config, next);
+
+    // Simulate the first response
+    res.writeHead(200, {
+      "content-type": "application/json",
+      "x-header-ignored": "no"
+    });
+    res.end("cached response body");
+
+    // Assertions for the first request
+    expect(next).toHaveBeenCalled(); // Proceed to next middleware during first request
+
+    // Reset mocks for the second invocation
+    jest.clearAllMocks();
+    next.mockReset();
+    res.setHeader = jest.fn();
+    res.removeHeader = jest.fn();
+    res.writeHead = jest.fn();
+    res.write = jest.fn();
+    res.end = jest.fn();
+
+    // Second request: retrieve from cache
+    parseCacheControl.mockReturnValue({});
+    isCacheValid.mockReturnValue(true); // Simulate a valid cache entry
+
+    mod(req, res, logFacilities, config, next);
+
+    // Assertions for the second request
+    expect(logFacilities.resmessage).toHaveBeenCalledWith(
+      "The response is cached."
+    );
+    expect(res.setHeader).toHaveBeenCalledWith("X-SVRJS-Cache", "HIT");
+    expect(res.writeHead).toHaveBeenCalledWith(200, {
+      "cache-control": "max-age=300",
+      "content-type": "application/json"
+    });
+    expect(res.end).toHaveBeenCalledWith(
+      Buffer.from("cached response body", "latin1")
+    );
+    expect(next).not.toHaveBeenCalled(); // No middleware should be called
+  });
+
   test("should validate config values correctly", () => {
     const validConfig = {
       cacheVaryHeaders: ["accept", "user-agent"],
+      cacheIgnoreHeaders: ["set-cookie"],
       maximumCachedResponseSize: 2048
     };
 
     expect(
       mod.configValidators.cacheVaryHeaders(validConfig.cacheVaryHeaders)
     ).toBe(true);
+    expect(
+      mod.configValidators.cacheIgnoreHeaders(validConfig.cacheIgnoreHeaders)
+    ).toBe(true);
     expect(
       mod.configValidators.maximumCachedResponseSize(
         validConfig.maximumCachedResponseSize
@@ -137,12 +199,16 @@ describe("SVR.JS Cache mod", () => {
 
     const invalidConfig = {
       cacheVaryHeaders: "invalid",
+      cacheIgnoreHeaders: "invalid",
       maximumCachedResponseSize: "invalid"
     };
 
     expect(
       mod.configValidators.cacheVaryHeaders(invalidConfig.cacheVaryHeaders)
     ).toBe(false);
+    expect(
+      mod.configValidators.cacheIgnoreHeaders(invalidConfig.cacheIgnoreHeaders)
+    ).toBe(false);
     expect(
       mod.configValidators.maximumCachedResponseSize(
         invalidConfig.maximumCachedResponseSize