From d2121c76cbb6db4574f9ef3e88ecb96c891f3a02 Mon Sep 17 00:00:00 2001
From: Lonami Exo <totufals@hotmail.com>
Date: Fri, 29 Dec 2017 19:41:12 +0100
Subject: [PATCH] Fetch and persist each auth_key per DC

---
 telethon/tl/session.py | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/telethon/tl/session.py b/telethon/tl/session.py
index 193c6d44..8c2850bf 100644
--- a/telethon/tl/session.py
+++ b/telethon/tl/session.py
@@ -168,6 +168,17 @@ class Session:
         self._port = port
         self._update_session_table()
 
+        # Fetch the auth_key corresponding to this data center
+        c = self._conn.cursor()
+        c.execute('select auth_key from sessions')
+        tuple_ = c.fetchone()
+        if tuple_:
+            from ..crypto import AuthKey
+            self._auth_key = AuthKey(data=tuple_[0])
+        else:
+            self._auth_key = None
+        c.close()
+
     @property
     def server_address(self):
         return self._server_address
@@ -188,8 +199,7 @@ class Session:
     def _update_session_table(self):
         with self._db_lock:
             c = self._conn.cursor()
-            c.execute('delete from sessions')
-            c.execute('insert into sessions values (?,?,?,?)', (
+            c.execute('insert or replace into sessions values (?,?,?,?)', (
                 self._dc_id,
                 self._server_address,
                 self._port,