[CST-5729] Change in order to save header only if configured and existing

server.ts

@@ -375,13 +375,13 @@ function cacheCheck(req, res, next) {
 
   // If cached copy exists, return it to the user.
   if (cachedCopy && cachedCopy.page) {
-    if (cachedCopy.headers && Array.isArray(environment.cache.serverSide.headers) && environment.cache.serverSide.headers.length > 0) {
-      environment.cache.serverSide.headers.forEach((header) => {
-        if (cachedCopy.headers[header.toLowerCase()]) {
+    if (cachedCopy.headers) {
+      Object.keys(cachedCopy.headers).forEach((header) => {
+        if (cachedCopy.headers[header]) {
           if (environment.cache.serverSide.debug) {
             console.log(`Restore cached ${header} header`);
           }
-          res.setHeader(header, cachedCopy.headers[header.toLowerCase()]);
+          res.setHeader(header, cachedCopy.headers[header]);
         }
       });
     }
@@ -462,8 +462,8 @@ function saveToCache(req, page: any) {
     // Avoid caching "/reload/[random]" paths (these are hard refreshes after logout)
     if (key.startsWith('/reload')) { return; }
 
-    // Retrieve response headers
-    const headers = req.res.getHeaders();
+    // Retrieve response headers to save, if any
+    const headers = retrieveHeaders(req.res);
     // If bot cache is enabled, save it to that cache if it doesn't exist or is expired
     // (NOTE: has() will return false if page is expired in cache)
     if (botCacheEnabled() && !botCache.has(key)) {
@@ -479,6 +479,21 @@ function saveToCache(req, page: any) {
   }
 }
 
+function retrieveHeaders(response) {
+  const headers = Object.create({});
+  if (Array.isArray(environment.cache.serverSide.headers) && environment.cache.serverSide.headers.length > 0) {
+    environment.cache.serverSide.headers.forEach((header) => {
+      if (response.hasHeader(header)) {
+        if (environment.cache.serverSide.debug) {
+          console.log(`Save ${header} header to cache`);
+        }
+        headers[header] = response.getHeader(header);
+      }
+    });
+  }
+
+  return headers;
+}
 /**
  * Whether a user is authenticated or not
  */

src/config/cache-config.interface.ts

@@ -13,7 +13,7 @@ export interface CacheConfig extends Config {
   serverSide: {
     // Debug server-side caching.  Set to true to see cache hits/misses/refreshes in console logs.
     debug: boolean,
-    // List of headers to restore from the cache hit
+    // List of response headers to save into the cache
     headers: string[],
     // Cache specific to known bots.  Allows you to serve cached contents to bots only.
     botCache: {

src/environments/environment.test.ts

@@ -59,6 +59,7 @@ export const environment: BuildConfig = {
     // In-memory cache of server-side rendered pages. Disabled in test environment (max=0)
     serverSide: {
       debug: false,
+      headers: ['Link'],
       botCache: {
         max: 0,
         timeToLive: 24 * 60 * 60 * 1000, // 1 day