added cache system

frontend/js/api.js

@@ -23,6 +23,80 @@ const api = {
      */
     clearToken() {
         localStorage.removeItem('access_token');
+        this.clearCache();
+    },
+
+    /**
+     * Get data with caching - Returns Response obj or Mock Response
+     * @param {string} url - API endpoint
+     * @param {number} ttlMinutes - Time to live in minutes (default 60)
+     */
+    async getCached(url, ttlMinutes = 60) {
+        const cacheKey = 'cache_' + url;
+        const cachedItem = localStorage.getItem(cacheKey);
+
+        if (cachedItem) {
+            try {
+                const { data, timestamp } = JSON.parse(cachedItem);
+                const age = (Date.now() - timestamp) / 1000 / 60;
+
+                if (age < ttlMinutes) {
+                    console.log(`[Cache] Hit for ${url}`);
+                    // Return a mock response-like object
+                    return {
+                        ok: true,
+                        status: 200,
+                        json: async () => data
+                    };
+                } else {
+                    console.log(`[Cache] Expired for ${url}`);
+                    localStorage.removeItem(cacheKey);
+                }
+            } catch (e) {
+                console.error('[Cache] Error parsing cache', e);
+                localStorage.removeItem(cacheKey);
+            }
+        }
+
+        console.log(`[Cache] Miss for ${url}`);
+        const response = await this.get(url);
+
+        if (response && response.ok) {
+            try {
+                // Clone response to read body and still return it to caller
+                const clone = response.clone();
+                const data = await clone.json();
+
+                localStorage.setItem(cacheKey, JSON.stringify({
+                    data: data,
+                    timestamp: Date.now()
+                }));
+            } catch (e) {
+                console.warn('[Cache] failed to save to localStorage', e);
+            }
+        }
+
+        return response;
+    },
+
+    /**
+     * Invalidate specific cache key
+     */
+    invalidateCache(url) {
+        localStorage.removeItem('cache_' + url);
+        console.log(`[Cache] Invalidated ${url}`);
+    },
+
+    /**
+     * Clear all API cache
+     */
+    clearCache() {
+        Object.keys(localStorage).forEach(key => {
+            if (key.startsWith('cache_')) {
+                localStorage.removeItem(key);
+            }
+        });
+        console.log('[Cache] Cleared all cache');
     },
 
     /**
@@ -37,14 +111,36 @@ const api = {
      * Call this on page load to verify auth status
      */
     async checkAuth() {
-        // Try to get current user - works with Authelia headers or JWT
-        const response = await fetch('/api/auth/me', {
+        const url = '/api/auth/me';
+        // 1. Try Cache (Short TTL: 5 min)
+        const cacheKey = 'cache_' + url;
+        const cachedItem = localStorage.getItem(cacheKey);
+        if (cachedItem) {
+            try {
+                const { data, timestamp } = JSON.parse(cachedItem);
+                if ((Date.now() - timestamp) / 1000 / 60 < 5) {
+                    this._autheliaAuth = true;
+                    return data;
+                }
+            } catch (e) { localStorage.removeItem(cacheKey); }
+        }
+
+        // 2. Fetch from Network
+        const response = await fetch(url, {
             headers: this.getToken() ? { 'Authorization': `Bearer ${this.getToken()}` } : {}
         });
 
         if (response.ok) {
             this._autheliaAuth = true;
-            return await response.json();
+            const data = await response.json();
+
+            // Save to Cache
+            localStorage.setItem(cacheKey, JSON.stringify({
+                data: data,
+                timestamp: Date.now()
+            }));
+
+            return data;
         }
 
         this._autheliaAuth = false;