如何在单独的线程中运行websocket服务器？

Question

我正在使用 Python 创建一个桌面应用程序，并使用 Vue 3 编写 GUI，并且我需要在单独的线程中运行 WebSocket 服务器。问题是 WebSocket 服务器必须持续侦听传入连接以实现与客户端的实时通信，并且我不确定如何在新线程中运行它，这是必要的，因为否则 GUI 将无法启动。有谁知道应该如何实施？因为我不知道该怎么做。

主要代码：

import asyncio
import webview
import threading
from services.HttpServer import HttpServerService
from services.WebSocket import WebSocketService
 
def on_loaded(window_ready):
    webview.windows[0].events.loaded -= on_loaded
    print('Val', window_ready);
    if (window_ready):
        webview.windows[0].set_window_size(width=1200, height=800)
 
class App:
    def __init__(self):
        self.http_server_thread = None
        self.websocket_thread = None
        self.client_ui_thread = None
        self.websocket = None
        self.client_ui = None
        self.webview = webview
 
    async def start(self):
        self.http_server_thread = threading.Thread(target=HttpServerService("127.0.0.1", 8001).start)
        self.http_server_thread.daemon = True  # Set the thread as daemon
        self.http_server_thread.start()
 
        self.websocket = WebSocketService("127.0.0.1", 8008)
        self.websocket_thread = threading.Thread(target=await self.websocket.start)
        self.websocket_thread.daemon = True  # Set the thread as daemon
        self.websocket_thread.start()
 
        self.client_ui = webview.create_window("CrowdQuant", url="http://127.0.0.1:8001", width=1024, height=770,
                                               resizable=False, frameless=True)
        self.client_ui.events.loaded += lambda: self.websocket.on_message(variable_name="window_ready",
                                                                          handle_message_fn=lambda
                                                                              window_ready: on_loaded(window_ready))
 
        self.client_ui_thread = threading.Thread(target=webview.start)  # gui="cef"
        self.client_ui_thread.daemon = True  # Set the thread as daemon
        self.client_ui_thread.start()

if __name__ == "__main__":
    asyncio.run(App().start())

WebSocket服务代码：

import json
import asyncio
import websockets
 
class WebSocketService:
    def __init__(self, address="127.0.0.0", port=8008):
        self.socket = None
        self.url = (address, port)
        self.variable_name = None
        self.handle_message_fn = None
        self.server = None
        self.clients = set()
 
    async def start(self):
        await self.start_server()
        await self.start_client()
 
    async def start_server(self):
        while True:
            try:
                self.server = await websockets.serve(self.handle_client_connection, self.url[0], self.url[1])
                print(f"WebSocket server started at ws://{self.url[0]}:{self.url[1]}")
                await self.server.wait_closed()
            except OSError:
                print(f"Address {self.url[0]}:{self.url[1]} already in use. Retrying...")
                await asyncio.sleep(5)
 
    async def handle_client_connection(self, websocket):
        self.clients.add(websocket)
        try:
            async for message in websocket:
                await self.handle_message(message)
        finally:
            self.clients.remove(websocket)
 
    async def stop(self):
        await self.stop_client()
        await self.stop_server()
 
    async def stop_server(self):
        if self.server:
            self.server.close()
            await self.server.wait_closed()
 
    @staticmethod
    def on_error(error):
        print('WebSocket error:', error)

Answer 1

您的实施似乎总体上是在正确的轨道上，但有一些问题需要解决。让我们一步一步地看一下它们。

线程中的异步：您正在尝试将异步与线程一起使用，这并不简单。尽管可以在线程中运行 asyncio，但由于其复杂性和潜在的问题，通常不建议这样做。

启动 WebSocket 服务：由于 asyncio 不容易与设置中的线程集成，因此您应该考虑直接在 asyncio 事件循环中运行 WebSocket 服务器，而不是尝试在单独的线程中运行它。

以下是如何修改代码以将 WebSocket 服务器集成到 asyncio 事件循环中：

import asyncio
import webview
import threading
from services.HttpServer import HttpServerService
from services.WebSocket import WebSocketService

def on_loaded(window_ready):
    webview.windows[0].events.loaded -= on_loaded
    print('Val', window_ready);
    if (window_ready):
        webview.windows[0].set_window_size(width=1200, height=800)

class App:
    def __init__(self):
        self.http_server_thread = None
        self.client_ui_thread = None
        self.websocket = None
        self.client_ui = None
        self.webview = webview

    async def start(self):
        self.http_server_thread = threading.Thread(target=HttpServerService("127.0.0.1", 8001).start)
        self.http_server_thread.daemon = True
        self.http_server_thread.start()

        self.websocket = WebSocketService("127.0.0.1", 8008)
        await self.websocket.start_server()  # Start WebSocket server directly

        self.client_ui = webview.create_window("CrowdQuant", url="http://127.0.0.1:8001", width=1024, height=770,
                                               resizable=False, frameless=True)
        self.client_ui.events.loaded += lambda: self.websocket.on_message(variable_name="window_ready",
                                                                          handle_message_fn=lambda
                                                                              window_ready: on_loaded(window_ready))

        self.client_ui_thread = threading.Thread(target=webview.start)
        self.client_ui_thread.daemon = True
        self.client_ui_thread.start()

if __name__ == "__main__":
    asyncio.run(App().start())

对于 WebSocketService，您可以保持代码不变，因为它已经正确使用了 asyncio。

通过进行这些更改，您应该让 WebSocket 服务器与 GUI 应用程序一起运行，而不需要线程。