added optimised OS codes

CNP/Wireshark/SMTP/smtp-server.py

@@ -0,0 +1,33 @@
+import asyncio
+import uvloop
+from aiosmtpd.controller import Controller
+
+# handler that just prints the message content
+class PrintHandler:
+    async def handle_DATA(self, server, session, envelope):
+        print("Message from:", envelope.mail_from)
+        print("Recipients:", envelope.rcpt_tos)
+        print("Message data:")
+        print(envelope.content.decode('utf8', errors='replace'))
+        print("End of message")
+        # Respond with a success code
+        return '250 Message accepted for delivery'
+
+# uvloop for better performance
+asyncio.set_event_loop_policy(uvloop.EventLoopPolicy())
+
+def run_server():
+    # SMTP server controller, binding to localhost on port 25
+    controller = Controller(PrintHandler(), hostname='127.0.0.1', port=25)
+    controller.start()
+    print("SMTP server running on port 25. Press Ctrl+C to stop.")
+    try:
+        # Run forever
+        asyncio.get_event_loop().run_forever()
+    except KeyboardInterrupt:
+        pass
+    finally:
+        controller.stop()
+
+if __name__ == '__main__':
+    run_server()