lab3完成代码部分

Labs/Lab3/src/Receiver.py

@@ -1,18 +1,22 @@
 import socket
 import random
-import re
+import time
 
 class NetworkLayer:
-    def __init__(self, host="172.29.68.245", port=23666) -> None:
+    def __init__(self, host:str, port:int) -> None:
         self.socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
         self.socket.connect((host, port))
+        print("下层的不可靠传输连接成功，等待发送方传输。")
 
     def udt_send(self, data:str):
         self.socket.send(data.encode())
 
     def udt_rcv(self) -> str:
-        message = self.socket.recv(1024).decode("utf-8")
+        message = self.socket.recv(12).decode("utf-8")
         return message
+    
+    def close(self):
+        self.socket.close()
                 
 
 class ApplicationLayer:
@@ -22,13 +26,13 @@ class ApplicationLayer:
 
 class Receiver:
     def __init__(self, networkLayer:NetworkLayer, applicationLayer:ApplicationLayer):
-        self.expected_seq_num = 0
+        self.expected_seq_num = 1
         self.networkLayer = networkLayer
         self.applicationLayer = applicationLayer
         
     def deliver_data(self, data, seq_num):
         if seq_num == self.expected_seq_num:
-            print(f'成功收到seq_num={seq_num}, data={data}的包。')
+            print(f'成功收到seq_num={seq_num}, data=\"{data}\"的包。')
             self.applicationLayer.data.append(data)
             self.udt_send(seq_num)
             self.expected_seq_num += 1
@@ -39,30 +43,28 @@ class Receiver:
     def udt_send(self, ack_num):
         print(f"发送ACK={ack_num}", end="")
         if random.random() > 0.25:
-            self.networkLayer.socket.send((str(ack_num) + "\n").encode())
+            self.networkLayer.socket.send("{:0>4d}".format(ack_num).encode())
         else:
             print("，此包丢失。", end="")
         print()
 
     def extract(self, message:str):
-        try:
-            parts = message.split(" ")
-            seq_num = int(parts[0])
-            data = parts[1]
-            return seq_num, data
-        except Exception as e:
-            print(e)
-            return None, None
+        seq_num = int(message[:3])
+        data = message[4:]
+        return seq_num, data
 
 if __name__ == "__main__":
-    networkLayer = NetworkLayer()
+    max_seq_num = 20
+    networkLayer = NetworkLayer(host="172.29.68.245", port=23666)
     applicationLayer = ApplicationLayer()
     receiver = Receiver(networkLayer, applicationLayer)
     while True:
         message = networkLayer.udt_rcv()
         if message:
             seq_num, data = receiver.extract(message)
-            if data:
-                receiver.deliver_data(data, seq_num)
-
+            receiver.deliver_data(data, seq_num)
+            if receiver.expected_seq_num == max_seq_num:
+                break
+    print("序列传输完成。")
+    networkLayer.close()