Added simple non-expiring caching to Posts API

refs https://github.com/TryGhost/Toolbox/issues/522

- The public posts "browse" endpoint is causing the most strain on the instance performance. Caching responses with small TTL would allow to reduce the amount of request processing.

ghost/core/core/server/api/endpoints/posts-public.js

@@ -13,6 +13,7 @@ module.exports = {
     docName: 'posts',
 
     browse: {
+        cache: postsPublicService.api?.cache,
         options: [
             'include',
             'filter',

ghost/core/core/server/services/posts-public/service.js

@@ -12,17 +12,29 @@ class PostsPublicServiceWrapper {
 
         let postsCache;
         if (config.get('hostSettings:postsPublicCache:enabled')) {
-            postsCache = adapterManager.getAdapter('cache:postsPublic');
+            const cache = adapterManager.getAdapter('cache:postsPublic');
+            postsCache = new EventAwareCacheWrapper({
+                cache: cache,
+                resetEvents: ['site.changed'],
+                eventRegistry: EventRegistry
+            });
         }
 
-        const {PublicResourcesRepository} = require('@tryghost/public-resource-repository');
+        let cache;
-
+        if (postsCache) {
-        this.postsRepository = new PublicResourcesRepository({
+            // @NOTE: exposing cache through getter and setter to not loose the context of "this"
-            Model: Post,
+            cache = {
-            cache: postsCache
+                get() {
-        });
+                    return postsCache.get(...arguments);
+                },
+                set() {
+                    return postsCache.set(...arguments);
+                }
+            };
+        }
 
         this.api = {
+            cache: cache,
             browse: this.postsRepository.getAll.bind(this.postsRepository)
         };
     }

ghost/public-resource-repository/lib/PublicResourcesRepository.js

@@ -10,7 +10,7 @@ module.exports = class PublicResourcesRepository {
     /**
      * @param {object} deps
      * @param {object} deps.Model Bookshelf Model instance of TagPublic/Post/Author etc.
-     * @param {object} deps.cache cache instance
+     * @param {object} [deps.cache] cache instance
      */
     constructor(deps) {
         this.#Model = deps.Model;