Rename ApiCacheManager to add .js file extension

server/managers/ApiCacheManager.js

@@ -0,0 +1,51 @@
+const { LRUCache } = require('lru-cache')
+const Logger = require('../Logger')
+const Database = require('../Database')
+
+class ApiCacheManager {
+
+  defaultCacheOptions = { max: 1000, maxSize: 10 * 1000 * 1000, sizeCalculation: item => item.length }
+  defaultTtlOptions = { ttl: 30 * 60 * 1000 }
+
+  constructor(cache = new LRUCache(this.defaultCacheOptions), ttlOptions = this.defaultTtlOptions) {
+    this.cache = cache
+    this.ttlOptions = ttlOptions
+  }
+
+  init(database = Database) {
+    let hooks = ['afterCreate', 'afterUpdate', 'afterDestroy', 'afterBulkCreate', 'afterBulkUpdate', 'afterBulkDestroy']
+    hooks.forEach(hook => database.sequelize.addHook(hook, (model) => this.clear(model, hook)))
+  }
+
+  clear(model, hook) {
+    Logger.debug(`[ApiCacheManager] ${model.constructor.name}.${hook}: Clearing cache`)
+    this.cache.clear()
+  }
+
+  get middleware() {
+    return (req, res, next) => {
+      const key = { user: req.user.username, url: req.url }
+      const stringifiedKey = JSON.stringify(key)
+      Logger.debug(`[ApiCacheManager] count: ${this.cache.size} size: ${this.cache.calculatedSize}`)
+      const cached = this.cache.get(stringifiedKey)
+      if (cached) {
+        Logger.debug(`[ApiCacheManager] Cache hit: ${stringifiedKey}`)
+        res.send(cached)
+        return
+      }
+      res.originalSend = res.send
+      res.send = (body) => {
+        Logger.debug(`[ApiCacheManager] Cache miss: ${stringifiedKey}`)
+        if (key.url.search(/^\/libraries\/.*?\/personalized/) !== -1) {
+          Logger.debug(`[ApiCacheManager] Caching with ${this.ttlOptions.ttl} ms TTL`)
+          this.cache.set(stringifiedKey, body, this.ttlOptions)
+        } else {
+          this.cache.set(stringifiedKey, body)
+        }
+        res.originalSend(body)
+      }
+      next()
+    }
+  }
+}
+module.exports = ApiCacheManager