Basic flood control

Author: root

README.md

@@ -62,6 +62,9 @@ A: Use `<ENTER>` to send messages. Use `<TAB>` to autocomplete usernames, exampl
 Q: How to find the date and time of the messages?  
 A: Hover over the messages, and a tooltip will show the date and time.
 
+Q: Is there a flood control feature?  
+A: The chat has a very basic flood control: a user cannot send more than 10 messages in 5 seconds.
+
 Q: Is there a way to prevent a particular username from being used by anyone except me?  
 A: The username `admin` is available *if and only if* the username `adminxyz` is entered in the input box. Change `adminxyz` to a private password in the beginning of `talktalktalk.py`, and as a result *noone else than you will be able to use the username `admin`.*
 

talktalktalk.html

@@ -58,6 +58,7 @@
 var users;
 var firstId;
 var lastId;
+var loop;
 
 function is_scrolled_end() { // See http://stackoverflow.com/a/40370876/1422096
     return ((window.innerHeight + window.pageYOffset) >= document.body.offsetHeight);
@@ -117,18 +118,15 @@
         $('#notifications').hide();
     }
 
-    function disconnected_message () {
-        $('#popup').text('Click anywhere or press any key to reload the page.').removeClass('hidden');
+    function popup_message (message, clicktoclosepopup, clicktoreload) {
+        $('#popup').text(message).removeClass('hidden');
         $(':not(.popup)').addClass('opaque');
-        $(document).on('click keydown', function() { $(document).off('click keydown'); $(document).off('keydown'); ws.close(); ready(); })
+        if (clicktoclosepopup)
+            $(document).on('click keydown', function() { $(document).off('click keydown'); $('#popup').addClass('hidden'); $(':not(#popup)').removeClass('opaque'); });
+        else if (clicktoreload)
+            $(document).on('click keydown', function() { $(document).off('click keydown'); $(document).off('keydown'); ws.close(); ready(); });
     }
 
-    function usernamechanged_message () {
-        $('#popup').text('Your username has been changed because the one you entered is reserved.').removeClass('hidden');
-        $(':not(.popup)').addClass('opaque');
-        $(document).on('click keydown', function() { $(document).off('click keydown'); $('#popup').addClass('hidden'); $(':not(#popup)').removeClass('opaque'); })
-    }    
-
     if (!window.WebSocket) {
         $('#popup').text('Your browser is not supported, please use another browser.').removeClass('hidden');
         $('#writing').prop('disabled', true);
@@ -164,17 +162,17 @@
     ws.onclose = function() { 
         setTimeout(function() { 
             if (ws.readyState != 0 && ws.readyState != 1)
-                disconnected_message();
+                popup_message('Click anywhere or press any key to reload the page.', false, true);
          }, 2000);
     };    
 
-    setInterval(function() {
+    loop = setInterval(function() {
         ws.send('ping');
         if (Date.now() - lastPong > 10000) { // disconnected from internet or phone idle mode; in both cases, ws.readyState can be 1 (OPEN) so we can't use that
             ws.send('ping');   // this is your last chance ! we send a packet now, and if in 1 second, nothings happen, this means we're dead
             setTimeout( function() {
                 if (Date.now() - lastPong > 10000)  // you missed your last chance !
-                    disconnected_message();         // disconnected from internet
+                    popup_message('Click anywhere or press any key to reload the page.', false, true);     // disconnected from internet
                 else                                // ok the phone was just idle, let's resume
                     ws.send(JSON.stringify({ "type" : "username", "username" : $('#username').text() }));  // let's send username again, so that other users see me
             }, 1000);
@@ -245,7 +243,13 @@
         else if (data['type'] === 'usernameunavailable') {
             $('#username').text(data['username']);
             localStorage.setItem("username", $('#username').text());
-            usernamechanged_message();
+            popup_message('Your username has been changed because the one you entered is reserved.', true, false);
+        }
+        else if (data['type'] === 'flood') {
+            popup_message('Please do not flood this chat.', false, false);
+            ws.onclose = undefined;
+            clearInterval(loop);
+            ws.close();
         }
         else if (data['type'] === 'displayeduser') {
             displayeduser = data['username'];
@@ -266,7 +270,8 @@
 
     $('#writing').keydown(function(e) {
         if (e.keyCode == 13 && !e.shiftKey) {
-            ws.send(JSON.stringify({ type: 'message', username: $('#username').text(), message: $('#writing').val().trim() }));
+            if ($('#writing').val().trim() !== '')
+                ws.send(JSON.stringify({ type: 'message', username: $('#username').text(), message: $('#writing').val().trim() }));
             $('#writing').val('');     
             e.preventDefault();  
         }

talktalktalk.py

@@ -16,6 +16,7 @@
 from gevent import pywsgi
 from geventwebsocket.handler import WebSocketHandler
 from geventwebsocket.exceptions import WebSocketError
+from collections import deque
 from config import PORT, HOST, ADMINNAME, ADMINHIDDENNAME, ALLOWEDTAGS
 
 idx = 0
@@ -37,6 +38,7 @@ def main():
 
     users = {}
     pings = {}
+    usermessagetimes = {}
 
     def send_userlist():
         for u in users.keys():
@@ -76,20 +78,32 @@ def dbworker():        # when a user disappears during more than 30 seconds (+/-
     @get('/ws', apply=[websocket])
     def chat(ws):
         global idx
+        usermessagetimes[ws] = deque(maxlen=10)
         while True:
             try:
                 receivedmsg = ws.receive()
                 if receivedmsg is not None:
+
                     receivedmsg = receivedmsg.decode('utf8')
                     if len(receivedmsg) > 4096:      # this user is probably a spammer
+                        ws.send(json.dumps({'type' : 'flood'}))
                         break
+
                     pings[ws] = time.time()
+
                     if receivedmsg == 'ping':         # ping/pong packet to make sure connection is still alive
                         ws.send('id' + str(idx-1))    # send the latest message id in return
                         if ws not in users:           # was deleted by dbworker
                             ws.send(json.dumps({'type' : 'username'}))
                     else:
+                        usermessagetimes[ws].append(time.time())                           # flood control
+                        if len(usermessagetimes[ws]) == usermessagetimes[ws].maxlen:
+                            if usermessagetimes[ws][-1] - usermessagetimes[ws][0] < 5:     # if more than 10 messages in 5 seconds (including ping messages)
+                                ws.send(json.dumps({'type' : 'flood'}))                    # disconnect the spammer
+                                break
+
                         msg = json.loads(receivedmsg)
+
                         if msg['type'] == 'message':
                             message = (bleach.clean(msg['message'], tags=ALLOWEDTAGS, strip=True)).strip()