fix: add cache expiry for API requests in fetch_paper.py

fetch_paper.py

@@ -12,14 +12,16 @@ from concurrent.futures import ThreadPoolExecutor, as_completed
 API_URL = "https://huggingface.co/api/daily_papers"
 
 cache = {}
+cache_expiry = {}
 
 
 def make_request(url: str):
     # Create a hash of the URL to use as the cache key
     url_hash = hashlib.md5(url.encode()).hexdigest()
+    current_time = datetime.datetime.now()
 
-    # Check if the response is already cached
-    if url_hash in cache:
+    # Check if the response is already cached and not expired
+    if url_hash in cache and (current_time - cache_expiry[url_hash]).seconds < 3600:
         print(f"Cache hit for URL: {url}")
         return cache[url_hash]
 
@@ -37,8 +39,9 @@ def make_request(url: str):
             response.raise_for_status()
             data = response.json()
 
-            # Cache the response
+            # Cache the response and set the expiry time
             cache[url_hash] = data
+            cache_expiry[url_hash] = current_time
 
             return data
         except requests.RequestException as e: