Merge pull request #266 from ShenYuhan/fix_mtime

fix update_cache() with no newwork

paddlehub/common/hub_server.py

@@ -283,17 +283,23 @@ class CacheUpdater(threading.Thread):
         api_url = srv_utils.uri_path(default_hub_server.get_server_url(),
                                      'search')
         cache_path = os.path.join(CACHE_HOME, RESOURCE_LIST_FILE)
+        if os.path.exists(cache_path):
             extra = {
                 "command": "update_cache",
                 "mtime": os.stat(cache_path).st_mtime
             }
+        else:
+            extra = {
+                "command": "update_cache",
+                "mtime": time.strftime("%Y-%m-%d %H:%M:%S", time.localtime())
+            }
         try:
             r = srv_utils.hub_request(api_url, payload, extra)
-        except Exception as err:
-            pass
             if r.get("update_cache", 0) == 1:
                 with open(cache_path, 'w+') as fp:
                     yaml.safe_dump({'resource_list': r['data']}, fp)
+        except Exception as err:
+            pass
 
     def run(self):
         self.update_resource_list_file(self.module, self.version)