Add save() and restore() capability

Author: rhettinger

pubsub/pubsub.py

@@ -13,6 +13,7 @@
 from heapq import merge
 from bisect import bisect
 from sys import intern
+import pickle
 import re
 
 User = str
@@ -101,3 +102,12 @@ def age(post: Post) -> str:
     divisor, unit = time_units[bisect(time_unit_cuts, seconds)]
     units = seconds // divisor
     return '%d %s ago' % (units, unit + ('' if units==1 else 's'))
+
+def save():
+    with open('pubsub.pickle', 'wb') as f:
+        pickle.dump([posts, user_posts, hashtag_index, following, followers, user_info], f)
+
+def restore():
+    global posts, user_posts, hashtag_index, following, followers, user_info
+    with open('pubsub.pickle', 'rb') as f:
+        posts, user_posts, hashtag_index, following, followers, user_info = pickle.load(f)

pubsub/session.py

@@ -34,6 +34,13 @@
 follow('raymondh', followed_user='barry')
 
 if __name__ == '__main__':
+    import pubsub
+
+    pubsub.save()
+    del pubsub.posts, pubsub.user_posts, pubsub.hashtag_index,
+    del pubsub.followers, pubsub.following, pubsub.user_info
+    pubsub.restore()
+
     from pubsub import posts, followers, following, user_info, hashtag_index
     from pubsub import posts_by_user, posts_for_user, search
     from pubsub import get_followers, get_followed, get_user, check_user, age