Add some private projects

soundcloud/soundcloud_problem_statement/python/main.py

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+import socket
+import threading
+
+EVENT_PORT = 9090
+CLIENT_PORT = 9099
+client_pool = {}
+follow_registry = {}
+seq_no_to_message = {}
+
+def event_server():
+    last_seq_no = 0
+
+    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as server:
+        server.bind(("127.0.0.1", EVENT_PORT))
+        server.listen()
+        print("Listening for events on %d" % EVENT_PORT)
+        while True:
+            event_socket, address = server.accept()
+            print('Accepted connection from {}:{}'.format(address[0], address[1]))
+            with event_socket:
+                with event_socket.makefile() as socket_file:
+                    for payload_line in socket_file:
+                        payload = payload_line.strip()
+                        print("Message received: %s" % payload)
+                        payload_parts = payload.split("|")
+
+                        seq_no_to_message[int(payload_parts[0])] = payload_parts
+
+                        while last_seq_no + 1 in seq_no_to_message:
+                            next_seq_no = last_seq_no + 1
+                            next_message = seq_no_to_message[next_seq_no]
+                            del seq_no_to_message[next_seq_no]
+
+                            kind = next_message[1]
+                            next_payload = "|".join(next_message)
+
+                            if kind == "F":
+                                from_user_id = int(next_message[2])
+                                to_user_id = int(next_message[3])
+
+                                if to_user_id not in follow_registry:
+                                    follow_registry[to_user_id] = set([])
+                                follow_registry[to_user_id].add(from_user_id)
+
+                                #if to_user_id in client_pool:
+                                #    client_pool[to_user_id].sendall(bytes(next_payload + "\n", "UTF-8"))
+
+                            elif kind == "U":
+                                from_user_id = int(next_message[2])
+                                to_user_id = int(next_message[3])
+
+                                if to_user_id not in follow_registry:
+                                    follow_registry[to_user_id] = set([])
+                                follow_registry[to_user_id].remove(from_user_id)
+
+                            elif kind == "P":
+                                to_user_id = int(next_message[3])
+
+                                if to_user_id in client_pool:
+                                    client_pool[to_user_id].sendall(bytes(next_payload + "\n", "UTF-8"))
+
+                            elif kind == "B":
+                                for client_id in client_pool:
+                                    client_pool[client_id].sendall(bytes(next_payload + "\n", "UTF-8"))
+
+                            elif kind == "S":
+                                from_user_id = int(next_message[2])
+
+                                if from_user_id in follow_registry:
+                                    for follower in follow_registry[from_user_id]:
+                                        if follower in client_pool:
+                                            client_pool[follower].sendall(bytes(next_payload + "\n", "UTF-8"))
+
+                            last_seq_no = next_seq_no
+
+def client_connection_server():
+    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as server:
+        server.bind(("127.0.0.1", CLIENT_PORT))
+        server.listen()
+        print("Listening for client requests on %d" % CLIENT_PORT)
+        while True:
+            client_socket, address = server.accept()
+            with client_socket.makefile() as f:
+                user_id_string = f.readline()
+                if user_id_string:
+                    user_id = int(user_id_string)
+                    client_pool[user_id] = client_socket
+                    print("User connected: %d (%d total)" % (user_id, len(client_pool)))
+
+if __name__ == "__main__":
+    thread1 = threading.Thread(target=event_server)
+    thread1.start()
+
+    thread2 = threading.Thread(target=client_connection_server)
+    thread2.start()
+
+    thread1.join()
+    thread2.join()