diff --git a/chat_box/consumers.py b/chat_box/consumers.py
deleted file mode 100644
index cb7cd18..0000000
--- a/chat_box/consumers.py
+++ /dev/null
@@ -1,76 +0,0 @@
-import json
-from channels.generic.websocket import AsyncWebsocketConsumer
-from .models import Message
-from django.urls import reverse
-from django.http import HttpResponse, HttpResponseRedirect
-from django.core import serializers
-
-from judge.jinja2.gravatar import gravatar
-from judge.models.profile import Profile
-
-
-class ChatConsumer(AsyncWebsocketConsumer):
-    async def connect(self):
-        self.room_name = 'room'
-        self.room_group_name = 'chat_%s' % self.room_name
-
-        # Join room group
-        await self.channel_layer.group_add(
-            self.room_group_name,
-            self.channel_name,
-        )
-
-        await self.accept()
-
-    async def disconnect(self, close_code):
-        # Leave room group
-        await self.channel_layer.group_discard(
-            self.room_group_name,
-            self.channel_name,
-        )
-
-    # Receive message from WebSocket
-    async def receive(self, text_data):
-        text_data_json = json.loads(text_data)
-        message = text_data_json['message']
-
-        author = self.scope['user']
-        author = Profile.objects.get(user=author)
-
-        message['author'] = author.username
-        message['css_class'] = author.css_class
-        message['image'] = gravatar(author, 32)
-
-        message_saved = save_data_and_return(message, author)
-        message['time'] = message_saved[0]['fields']['time']
-        message['id'] = message_saved[0]['pk']
-
-        # Send message to room group
-        await self.channel_layer.group_send(
-            self.room_group_name,
-            {
-                'type': 'chat_message',
-                'message': message,
-            },
-        )
-
-    # Receive message from room group
-    async def chat_message(self, event):
-        message = event['message']
-        # Send message to WebSocket
-        await self.send(text_data=json.dumps({
-            'message': message,
-        }))
-
-
-# return time
-def save_data_and_return(message, author):
-    new_message = Message(body=message['body'],
-                          author=author,
-                          )
-    new_message.save()
-    json_data = serializers.serialize("json", 
-                                        Message.objects
-                                               .filter(pk=new_message.id)
-                                      )
-    return json.loads(json_data)
\ No newline at end of file
diff --git a/judge/utils/problem_data.py b/judge/utils/problem_data.py
index da26e60..5954895 100644
--- a/judge/utils/problem_data.py
+++ b/judge/utils/problem_data.py
@@ -1,3 +1,4 @@
+import hashlib
 import json
 import os
 import re
@@ -248,7 +249,7 @@ def get_visible_content(data):
 
 
 def get_file_cachekey(file):
-    return file.replace(' ', '===')
+    return hashlib.sha1(file.encode()).hexdigest()
 
 def get_problem_case(problem, files):
     result = {}
diff --git a/templates/chat/chat.html b/templates/chat/chat.html
index 620cc5e..8bc2d49 100644
--- a/templates/chat/chat.html
+++ b/templates/chat/chat.html
@@ -47,7 +47,6 @@
     function remove_day_if_today() {
         $('.message_date').each(function() {
             sent_date = $(this).html()
-            console.log(sent_date);
             if (sent_date === "{{today}}") {
                 $(this).hide();
             }
@@ -124,12 +123,14 @@
                     body: body,
                 };
 
+                $('#chat-input').val('');
+
                 $.post("{{ url('post_chat_message') }}", message)
                     .fail(function(res) {
                         console.log('Fail to send message');
                     })
                     .done(function(res, status) {
-                        $('#chat-input').val('').focus();
+                        $('#chat-input').focus();
                     })
             }
         });
@@ -196,6 +197,10 @@
                 })
         })
 
+        setInterval(function() {
+            $('#refresh-button').click();
+        }, 5 * 60 * 1000);
+
         $('#chat-box').scrollTop($('#chat-box')[0].scrollHeight);
         remove_day_if_today();
         load_dynamic_update({{last_msg}});
@@ -256,4 +261,4 @@
         </div>
     </div>
 
-{% endblock body %}
\ No newline at end of file
+{% endblock body %}