Python网络编程（八）-python websockets的使用，实现server和client的通信

川长思鸟来 2022-09-13 11:24 255阅读 0赞

**1. websocket简介：**

python3提供了websockets，用于web应用程序，本节介绍websockets相关内容。

**2.websockets常用方法：**

serve:在server端使用，等待客户端的连接。如果连接成功，返回一个websocket。

connect: 在client端使用，用于建立连接。

send:发送数据，server和client双方都可以使用。

recv:接收数据，server和client双方都可以使用。

close:关闭连接，server和client双方都可以使用。

**3.举例：一个简单的测试程序：**

程序清单：

**Server端代码：**

import asyncio
    import websockets
    
    IP_ADDR = "127.0.0.1"
    IP_PORT = "8888"
    
    # 握手，通过接收hello，发送"123"来进行双方的握手。
    async def serverHands(websocket):
        while True:
            recv_text = await websocket.recv()
            print("recv_text=" + recv_text)
            if recv_text == "hello":
                print("connected success")
                await websocket.send("123")
                return True
            else:
                await websocket.send("connected fail")
    
    
    # 接收从客户端发来的消息并处理，再返给客户端ok
    async def serverRecv(websocket):
        while True:
            recv_text = await websocket.recv()
            print("recv:", recv_text)
            await websocket.send("ok!!!")
    
    
    # 握手并且接收数据
    async def serverRun(websocket, path):
        print(path)
        await serverHands(websocket)
    
        await serverRecv(websocket)
    
    #main function
    if __name__ == '__main__':
        print("======server main begin======")
        server = websockets.serve(serverRun, IP_ADDR, IP_PORT)
        asyncio.get_event_loop().run_until_complete(server)
        asyncio.get_event_loop().run_forever()

serve（），用于等待客户端的连接。如果客户端调用connect方法成功，则返回一个websocket。

**Client端代码：**

import asyncio
    import websockets
    
    IP_ADDR = "127.0.0.1"
    IP_PORT = "8888"
    
    # 握手，通过发送hello，接收"123"来进行双方的握手。
    async def clientHands(websocket):
        while True:
            await websocket.send("hello")
            response_str = await websocket.recv()
            if "123" in response_str:
                print("握手成功")
                return True
    
    
    # 向服务器端发送消息
    async def clientSend(websocket):
        while True:
            input_text = input("input text: ")
            if input_text == "exit":
                print(f'"exit", bye!')
                await websocket.close(reason="exit")
                return False
            await websocket.send(input_text)
            recv_text = await websocket.recv()
            print(f"{recv_text}")
    
    
    # 进行websocket连接
    async def clientRun():
        ipaddress = IP_ADDR + ":" + IP_PORT
        async with websockets.connect("ws://" + ipaddress) as websocket:
            await clientHands(websocket)
    
            await clientSend(websocket)
    
    #main function
    if __name__ == '__main__':
        print("======client main begin======")
        asyncio.get_event_loop().run_until_complete(clientRun())

通过调用connect方法与服务的建立通信。

通过发送"hello"，接收"123"来进行双方握手的校验，只有握手成功，才可以继续发送和接收数据。

**运行结果：**

**客户端运行结果：**

> python myclient.py  
> ======client main begin======  
> 握手成功  
> input text: hello python  
> ok!!!  
> input text: hello c  
> ok!!!  
> input text: hello java  
> ok!!!  
> input text: exit  
> "exit", bye!
> 
> Process finished with exit code 0  
>

**服务端运行结果：**

> python myserver.py  
> ======server main begin======  
> /  
> recv\_text=hello  
> connected success  
> recv: hello python  
> recv: hello c  
> recv: hello java  
> connection handler failed  
> Traceback (most recent call last):  
> File "/Users/aibook/PycharmProjects/py1/venv/lib/python3.8/site-packages/websockets/legacy/server.py", line 224, in handler  
> await self.ws\_handler(self, path)  
> File "/Users/aibook/PycharmProjects/py1/myserver.py", line 33, in serverRun  
> await serverRecv(websocket)  
> File "/Users/aibook/PycharmProjects/py1/myserver.py", line 23, in serverRecv  
> recv\_text = await websocket.recv()  
> File "/Users/aibook/PycharmProjects/py1/venv/lib/python3.8/site-packages/websockets/legacy/protocol.py", line 552, in recv  
> await self.ensure\_open()  
> File "/Users/aibook/PycharmProjects/py1/venv/lib/python3.8/site-packages/websockets/legacy/protocol.py", line 929, in ensure\_open  
> raise self.connection\_closed\_exc()  
> websockets.exceptions.ConnectionClosedOK: received 1000 (OK) exit; then sent 1000 (OK) exit  
>