Implement a short-lived packet cache when client request is the same as previous.

This allows the client to re-send packets safely in case of network issues,
without the server duplicating the action.

Note that server-initiated requests are never cached.
...Which are only AP or Broadcast, so makes no difference, I guess.

1 files changed, 26 insertions, 1 deletions

diff --git a/server.py b/server.py
index 2e56ab7..3f60c08 100755
--- a/server.py
+++ b/server.py
@@ -18,7 +18,7 @@
 #################################################################################
 
 ## Global Modules
-import threading, time, json, syslog
+import threading, time, json, syslog, base64
 LOG_AUTH=(syslog.LOG_NOTICE | syslog.LOG_AUTH)
 # Tweak as needed/desired
 
@@ -53,22 +53,45 @@ class WebSocketConn(WebSocket):
           If the frame is Binary then self.data is a bytearray object.
         """
         print("Message received from %s - %s" % (self.address[0], self.data))
+        print("Cache Recv: %s" % self.cacher)
+        print("Cache Send: %s" % self.caches)
+
+        # Check cache first
+        try:
+            if (base64.b64encode(bytearray(self.data, 'utf-8')) == self.cacher):
+                print("Replying from cache... (%s)" % self.caches)
+                self.send_message(self.caches)
+                if (self.caches == "NACK\n"):
+                    security.score(self, 1)
+                return
+            else:
+                print("Not cached, continue")
+        except:
+            traceback.print_exc()
+            stdout("Cache lookup skipped (ERROR)")
+
+        # Handle packet
         try:
             r=protocol.parse(self.data, self)
             stdout("Status: %s" % str(r[0]), 2)
             stdout("Reply: %s" % r[1], 2)
             if r[0] < PACKET_ACK:
+                self.caches    = "NACK\n"
                 stdout("%s - %s" % (self.address[0], r[1]))
                 syslog.syslog(LOG_AUTH, "%s - %s" % (self.address[0], r[1]))
                 self.send_message("NACK\n")
                 security.score(self, security.get_score(r[0]))
             else:
+                self.caches    = str(r[1])
                 self.send_message(str(r[1]))
         except:
             traceback.print_exc()
             self.send_message("ERROR\n")
+            self.caches = "ERROR\n"
 
         stdout("Message sent", 2)
+        self.cacher = base64.b64encode(bytearray(self.data, 'utf-8'))
+
         #stdout(self.address[0] + u' - %s' % (self.data))
         #self.send_message('ACK')
 
@@ -107,6 +130,8 @@ class WebSocketConn(WebSocket):
         self.MS_auth  = False
         self.token    = "0"
         self.userid   = 0
+        self.caches    = "INIT"
+        self.cacher    = "INIT"
 
     def handle_close(self):
         global clients