Dynamic Discovery, Client-Server

client.py

 import socket
 import threading
+from datetime import datetime
 
-def receive_messages():
-    while True:
-        try:
-            # Empfange Nachricht vom Server
-            data = client_socket.recv(1024)
-            print(data.decode('utf-8'))
-        except:
-            break
-
-# Client-Konfiguration
-host = '127.0.0.1'
-port = 5555
-
-# Verbinde zum Server
-client_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-client_socket.connect((host, port))
-print(f'Du bist jetzt im Chat')
-
-
-# Starte einen Thread, um Nachrichten vom Server zu empfangen
-receive_thread = threading.Thread(target=receive_messages)
-receive_thread.start()
-
-# Haupt-Thread zum Senden von Nachrichten
-while True:
-    message = input()
-    client_socket.send(message.encode('utf-8'))
+# Broadcast address and port
+BROADCAST_IP = "192.168.0.255"
+BROADCAST_PORT = 5973
+
+# Local host information
+MY_HOST = socket.gethostname()
+MY_IP = socket.gethostbyname(MY_HOST)
+
+
+
+class Client():
+    def __init__(self):
+        self.currentLeader = ''
+        self.server_socket = None
+
+    # print the current date and time
+    def printwt(self, msg):
+        current_date_time = datetime.now().strftime('%Y-%m-%d %H:%M:%S')
+        print(f'[{current_date_time}] {msg}')    
+
+    # dynamic discoverey: client sends request to server group and gets the IP of server as reply
+    def BroadcastSendAndReceive(self):
+
+        message = 'New client wants to connect: ' + MY_IP
+
+        # Create a UDP socket
+        broadcast_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+        # Send message on broadcast address
+        broadcast_socket.sendto(str.encode(message), (BROADCAST_IP, BROADCAST_PORT))
+
+        # Send broadcast message
+
+        self.printwt("Sent my IP to server group")
+
+        while True:     
+            try:
+                # receive reply data (server IP) from the other participants
+                reply, addr = broadcast_socket.recvfrom(1024)
+
+                if reply:
+                    # decode received data
+                    reply_addr = reply.decode()
+                    self.currentLeader = reply_addr
+                    self.printwt(f'Got Leader address: {self.currentLeader}')
+
+                    # Connect to the server using TCP
+                    self.server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+                    self.server_socket.connect((self.currentLeader, 5555))
+                    print("You have entered the chat room")
+
+                     # Starte einen Thread, um Nachrichten zu empfangen
+                    receive_thread = threading.Thread(target=self.receive_messages)
+                    receive_thread.start()
+
+                    # Haupt-Thread zum Senden von Nachrichten
+                    while True:
+                        message = input()
+                        timestamped_message = f'[{datetime.now().strftime("%Y-%m-%d %H:%M:%S")}] {message}'
+                        self.server_socket.send(timestamped_message.encode('utf-8'))
+                        
+            except socket.timeout:
+                pass
+
+    def receive_messages(self):
+        while True:
+            try:
+                data = self.server_socket.recv(1024)
+                if not data:
+                    break
+                print(data.decode('utf-8'))
+            except:
+                break
+
+
+
+
+# starting all simultaneously working procedures
+if __name__ == "__main__":
+    client = Client()
+
+    thread1 = threading.Thread(target = client.BroadcastSendAndReceive)
+    thread1.start()
+    thread1.join()
\ No newline at end of file

server.py

 import socket
 import threading
+from datetime import datetime
 
-def handle_client(client_socket, client_address):
-    while True:
-        try:
-            # Empfange Nachricht vom Client
-            data = client_socket.recv(1024)
-            if not data:
-                break
+# Listening port
+BROADCAST_PORT = 5973
+
+# Local host information
+MY_HOST = socket.gethostname()
+MY_IP = socket.gethostbyname(MY_HOST)
+
+class Server():
+    def __init__(self):
+        self.leader_IP = '' # fix the leader IP
+        self.clients = []
+
+    def printwt(self, msg):
+        current_date_time = datetime.now().strftime('%Y-%m-%d %H:%M:%S')
+        print(f'[{current_date_time}] {msg}')
+
+    # Listen to client broadcast (request) and reply with Server IP
+    def ListenForClientAndReply(self):
+        # Create a UDP socket
+        listen_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+        # Set the socket to broadcast and enable reusing addresses
+        listen_socket.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
+        listen_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+        # Bind socket to address and port
+        listen_socket.bind((MY_IP, BROADCAST_PORT))
 
-            # Sende die empfangene Nachricht an alle anderen Clients
-            broadcast(data, client_socket, client_address)
-        except:
-            break
+        print("Listening to broadcast messages")
 
-    # Client-Socket schließen
-    client_socket.close()
+        # Receiving broadcast massage
+        while True:
+            data, addr = listen_socket.recvfrom(1024)
 
-def broadcast(message, sender_socket, sender_address):
-    for client in clients:
-        try:
-            # Sende die Nachricht an alle Clients, außer an den Absender
-            if client != sender_socket:
-                client.send(f"{sender_address}: {message}".encode('utf-8'))
-        except:
-            # Entferne defekte Verbindungen
-            clients.remove(client)
+            if data:
+                self.printwt(data.decode())
 
-# Server-Konfiguration
-host = '127.0.0.1'
-port = 5555
+        # if Iam the leader, answer the client including my IP
+                # if MY_IP == self.leader_IP:
+                if data:
+                    reply_message = MY_IP
+                    listen_socket.sendto(str.encode(reply_message), addr)
+                    self.printwt('Replied my IP to new client')
 
-# Socket erstellen und binden
-server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-server_socket.bind((host, port))
-server_socket.listen(5)
+    def handle_client(self, client_socket, client_address):
+        self.clients.append(client_socket)
 
-print(f'Server lauscht auf {host}:{port}')
+        while True:
+            try:
+                data = client_socket.recv(1024)
+                if not data:
+                    break
+                self.broadcast(data, client_socket)
+
+            except:
+                self.clients.remove(client_socket)
+                break
+
+    def broadcast(self, message, sender_socket):
+        for client in self.clients:
+            try:
+                if client != sender_socket:
+                    client.send(message)
+            except:
+                self.clients.remove(client)
 
-# Liste für die verbundenen Clients
-clients = []
 
-while True:
-    # Warten auf eine Verbindung
-    client_socket, client_address = server_socket.accept()
+# starting all simultaneously working procedures
+if __name__== '__main__':
+    server = Server()
 
-    # Neuen Thread für jeden verbundenen Client erstellen
-    client_thread = threading.Thread(target=handle_client, args=(client_socket, client_address))
-    client_thread.start()
+    thread1 = threading.Thread(target = server.ListenForClientAndReply)
+    thread1.start()
+
+    # Socket erstellen und binden
+    server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+    server_socket.bind((MY_IP, 5555))
+    server_socket.listen(5)
+
+    while True:
+        client_socket, client_address = server_socket.accept()
 
-    # Client-Socket zur Liste hinzufügen
-    clients.append(client_socket)
+        client_thread = threading.Thread(target=server.handle_client, args=(client_socket, client_address))
+        client_thread.start()
\ No newline at end of file