fix(zopk): Add Brave API rate limit handling and heartbeat limit fix

Brave free tier was returning 429 for ~50% of queries due to back-to-back
requests. Added 1.1s delay between queries and retry with exponential
backoff (1.5s, 3s). Heartbeat endpoint exempted from Flask-Limiter and
interval increased from 30s to 60s to reduce log noise.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

blueprints/api/routes_analytics.py

@@ -13,6 +13,7 @@ from flask import jsonify, request, session, current_app
 from flask_login import current_user
 
 from database import SessionLocal, UserSession, UserClick, PageView, JSError
+from extensions import limiter
 from . import bp
 
 logger = logging.getLogger(__name__)
@@ -88,6 +89,7 @@ def api_analytics_track():
 
 
 @bp.route('/analytics/heartbeat', methods=['POST'])
+@limiter.exempt
 def api_analytics_heartbeat():
     """Keep session alive and update duration"""
     analytics_session_id = session.get('analytics_session_id')

static/js/analytics-tracker.js

@@ -7,7 +7,7 @@
 (function() {
     'use strict';
 
-    const HEARTBEAT_INTERVAL = 30000; // 30 seconds
+    const HEARTBEAT_INTERVAL = 60000; // 60 seconds
     const SCROLL_DEBOUNCE_MS = 500;
     const TRACK_ENDPOINT = '/api/analytics/track';
     const HEARTBEAT_ENDPOINT = '/api/analytics/heartbeat';

zopk_news_service.py

@@ -21,6 +21,7 @@ Created: 2026-01-11
 
 import os
 import re
+import time
 import hashlib
 import logging
 import unicodedata
@@ -678,6 +679,10 @@ class ZOPKNewsService:
 
                 if progress_callback:
                     progress_callback('search', f"Brave: {query_config['description']} ({len(brave_items)})", i + 1, len(BRAVE_QUERIES))
+
+                # Rate limit: Brave free tier ~1 req/s
+                if i < len(BRAVE_QUERIES) - 1:
+                    time.sleep(1.1)
         else:
             process_log.append({
                 'phase': 'search',
@@ -947,11 +952,14 @@ class ZOPKNewsService:
         }
 
     def _search_brave_single(self, query: str) -> List[NewsItem]:
-        """Search Brave API with a single query"""
+        """Search Brave API with a single query, with retry on 429"""
         if not self.brave_api_key:
             return []
 
         items = []
+        max_retries = 2
+
+        for attempt in range(max_retries + 1):
             try:
                 headers = {
                     'Accept': 'application/json',
@@ -959,8 +967,8 @@ class ZOPKNewsService:
                 }
                 params = {
                     'q': query,
-                'count': 10,  # Fewer results per query (we have 8 queries)
-                'freshness': 'pw',  # past week (more relevant than past month)
+                    'count': 10,
+                    'freshness': 'pw',
                     'country': 'pl',
                     'search_lang': 'pl'
                 }
@@ -986,11 +994,21 @@ class ZOPKNewsService:
                                 published_at=datetime.now(),
                                 image_url=item.get('thumbnail', {}).get('src')
                             ))
+                    break  # success
+                elif response.status_code == 429:
+                    if attempt < max_retries:
+                        wait = 1.5 * (2 ** attempt)  # 1.5s, 3s
+                        logger.warning(f"Brave API 429 for '{query[:30]}', retry {attempt+1} after {wait}s")
+                        time.sleep(wait)
+                    else:
+                        logger.error(f"Brave API 429 for '{query[:30]}' after {max_retries} retries, skipping")
                 else:
                     logger.error(f"Brave API error for '{query[:30]}': {response.status_code}")
+                    break
 
             except Exception as e:
                 logger.error(f"Brave search error: {e}")
+                break
 
         return items