From 02c955c702723236d34f01d4e6fe4c9b5da22a3a Mon Sep 17 00:00:00 2001
From: Nikolai Prokoschenko <nikolai@prokoschenko.de>
Date: Tue, 12 Mar 2013 19:47:20 +0100
Subject: [PATCH] Check for cache freshness

---
 yolk/pypi.py | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/yolk/pypi.py b/yolk/pypi.py
index 3ba3ba0..eecb8ac 100644
--- a/yolk/pypi.py
+++ b/yolk/pypi.py
@@ -1,4 +1,3 @@
-
 """
 
 pypi.py
@@ -26,6 +25,7 @@
     import xmlrpc.client as xmlrpclib
     import pickle
     import urllib.request as urllib2
+import sys
 import os
 import time
 import logging
@@ -208,9 +208,18 @@ def query_cached_package_list(self):
     def fetch_pkg_list(self):
         """Fetch and cache master list of package names from PYPI"""
         self.logger.debug("DEBUG: Fetching package name list from PyPI")
-        package_list = self.list_packages()
-        cPickle.dump(package_list, open(self.pkg_cache_file, "w"))
-        self.pkg_list = package_list
+        
+        if os.path.exists(self.pkg_cache_file):
+            st = os.stat(self.pkg_cache_file)
+            age = time.time() - st.st_mtime
+        else:
+            age = sys.maxint
+            
+        # Only fetch from PyPI if cache older than an hour
+        if age > 60 * 60:        
+            package_list = self.list_packages()
+            cPickle.dump(package_list, open(self.pkg_cache_file, "w"))
+            self.pkg_list = package_list
 
     def search(self, spec, operator):
         '''Query PYPI via XMLRPC interface using search spec'''