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python - 用于 mWebSocket 服务器的 Python WebSocket 客户端

问题描述

我正在尝试在 python 中构建一个 WebSocket 客户端，它通过以太网电缆每秒连接到一个 Arduino Uno，它上面有一个基于 mWebSocket 库的 WebSocket 服务器。工作的 Arduino 代码如下所示：

#include <WebSocketServer.h>
using namespace net;

// Enter a MAC address and IP address for your controller below.
// The IP address will be dependent on your local network:
byte mac[]{0xA8, 0x61, 0x0A, 0xAE, 0x69, 0x13};
IPAddress ip(198, 162, 1, 177);
IPAddress gateway(0,0,0,0);
IPAddress DNSserver(0,0,0,0);
IPAddress subnet(255,255,255,0);

constexpr uint16_t port = 80;
WebSocketServer wss{port};

void setup() {
  // You can use Ethernet.init(pin) to configure the CS pin
  
  Ethernet.init(10);  // Most Arduino shields
  //Ethernet.init(5);   // MKR ETH shield
  //Ethernet.init(0);   // Teensy 2.0
  //Ethernet.init(20);  // Teensy++ 2.0
  //Ethernet.init(15);  // ESP8266 with Adafruit Featherwing Ethernet
  //Ethernet.init(33);  // ESP32 with Adafruit Featherwing Ethernet

  // Open serial communications and wait for port to open:
  Serial.begin(9600);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
  }
  Serial.println("Ethernet WebServer Example");

  // start the Ethernet connection and the server:
  Ethernet.begin(mac,ip,DNSserver,gateway,subnet);

  // Check for Ethernet hardware present
  if (Ethernet.hardwareStatus() == EthernetNoHardware) {
    Serial.println("Ethernet shield was not found.  Sorry, can't run without hardware. :(");
    while (true) {
      delay(1); // do nothing, no point running without Ethernet hardware
    }
  }
  if (Ethernet.linkStatus() == LinkOFF) {
    Serial.println("Ethernet cable is not connected.");
  }

  // start the server
  Serial.print("server is at ");
  Serial.println(Ethernet.localIP());

  wss.onConnection([](WebSocket & ws) {
    const auto protocol = ws.getProtocol(); 
    if (protocol) {
      Serial.print(F("Client protocol: "));
      Serial.println(protocol);
    }

    ws.onMessage([](WebSocket & ws, const WebSocket::DataType dataType,
    const char *message, uint16_t length) {
      switch (dataType) {
        case WebSocket::DataType::TEXT:
          Serial.print(F("Received: "));
          Serial.println(message);
          break;
        case WebSocket::DataType::BINARY:
          Serial.println(F("Received binary data"));
          break;
      }

      ws.send(dataType, message, length);
    });

    ws.onClose([](WebSocket &, const WebSocket::CloseCode, const char *,
    uint16_t) {
      Serial.println(F("Disconnected"));
    });

    Serial.print(F("New client: "));
    Serial.println(ws.getRemoteIP());

    const char message[] {"Hello from Arduino server!"};
    ws.send(WebSocket::DataType::TEXT, message, strlen(message));
  });

  wss.begin();
  Serial.println(Ethernet.localIP());
}

void loop() {
  wss.listen();
}

我已经构建了一个 python 套接字客户端来与这个 Arduino 交互，并希望打印消息“来自 Arduino 服务器的你好！” 通过每个连接发送给客户端。

#!/usr/bin/python3
import asyncio
import websockets
import socket
import time
import datetime
import struct

starttime = time.time() # start value for timed data acquisition

# setup socket 1
s1 = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s1.connect(("198.162.1.177",80))
s1.sendall(b'GET / HTTP/1.1 400')
if True:
    print('Connected')
def acquire():
    
    data = s1.recv(10000)
    print(data)
        
while True:
   acquire()
   time.sleep(1.0 - ((time.time() - starttime) % 1.0)) # continue every  (2.0 seconds)

s1.close()

但是，当我运行上面的代码时。我获得：

Connected
b'H'
b'TTP/1.1 400 Bad Request\r\n'
b''
b''
b''
b''
b''

我在这里缺少什么，我认为连接没有完全建立，即使我可以从我的电脑上 ping Arduino。我是否需要以不同的方式为 WebSocket 客户端考虑 HTTP 标头？

标签： pythonhtmlsocketswebsocketarduino

解决方案

Websocket 连接是由带有升级标头的 HTTP 请求建立的，该标头指定连接客户端想要升级到 Websocket 协议。当服务器收到此消息并在请求中找到升级标头时，它会验证它是否支持的升级结束并将底层连接升级到 websocket 连接。这是您似乎缺少的东西。

此外，当您在客户端代码中导入 websockets 时。您可以使用为您完成这项工作的库函数，您只需使用请求 URL 中指定的“ws/wss”发出 GET 请求。

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