Fastapi Websocket 简明使用

Fastapi Websocket 简明使用

• 1.基于Fastapi 开发websocket 服务器端
• 2.基于Fastapi 开发websocket 客户端
  

环境

• github
• python3.7
• win10
• 依赖

	 pip install fastapi[all] websocket-client -i https://pypi.doubanio.com/simple

基于fastapi 实现 weboskcet

• main.py

from typing import List

from fastapi import FastAPI, WebSocket, WebSocketDisconnect
from fastapi.responses import HTMLResponse

app = FastAPI()

html = """


    
        
    
    
        
WebSocket Chat
        
Your ID: 
        

            
            Send
        
        

        
        
    

"""


class ConnectionManager:
    def __init__(self):
        self.active_connections: List[WebSocket] = []

    async def connect(self, websocket: WebSocket):
        await websocket.accept()
        self.active_connections.append(websocket)

    def disconnect(self, websocket: WebSocket):
        self.active_connections.remove(websocket)

    async def send_personal_message(self, message: str, websocket: WebSocket):
        await websocket.send_text(message)

    async def broadcast(self, message: str):
        for connection in self.active_connections:
            await connection.send_text(message)


manager = ConnectionManager()


@app.get("/")
async def get():
    return HTMLResponse(html)


@app.websocket("/ws/{client_id}")
async def websocket_endpoint(websocket: WebSocket, client_id: int):
    await manager.connect(websocket)
    try:
        while True:
            data = await websocket.receive_text()

            await manager.send_personal_message(f"You wrote: {data}", websocket)
            await manager.broadcast(f"Client #{client_id} says: {data}")
    except WebSocketDisconnect:
        manager.disconnect(websocket)
        await manager.broadcast(f"Client #{client_id} left the chat")

if __name__ == "__main__":
    import uvicorn
    uvicorn.run(
        app='main:app', 
        host="0.0.0.0",
        log_level="debug", 
        port=8000,
        loop="asyncio",
        # workers=4,
    )

• client.py

from fastapi import FastAPI,BackgroundTasks
from starlette.concurrency import run_in_threadpool
def create_app():
    app = FastAPI()
    return app

app = create_app()

@app.on_event("startup")
async def init_scheduler():
    from task import run
    run()
   
    

if __name__ =='__main__':
    import uvicorn
    uvicorn.run(
        app='client:app', 
        host="0.0.0.0",
        log_level="debug", 
        port=8888,
        loop="asyncio",
        # workers=4,
    )

• task.py

import websocket
import threading, time

def on_close(ws):
	'''
		- websocket client 重试机制
	'''
    print ("Retry : %s" % time.ctime())
    time.sleep(2)
    connect_websocket() # 每2s 重试一次
def on_open(ws):
	'''
		- 当系统连接上后的提示
	'''
    print('connection established')

def on_message(wsapp, message):
	'''
		- 接收服务器websocket 发送来的消息
	'''
    print(message)

def connect_websocket():
	'''
		- 尝试连接websocket 服务器
		- 并给该线程设置守护
	'''
    ws = websocket.WebSocketApp(
        "ws://192.168.144.81:8000/ws/2323", 
        on_open = on_open, 
        on_close = on_close,
        cookie="chocolate",
        on_message=on_message
        )
    wst = threading.Thread(target=ws.run_forever)
    wst.daemon = True
    wst.start()

def run():
'''
	- websocket 组件会跟随fastapi 主进程启动
	- 客户端系统会每隔2s 尝试一次连接
'''
    try:
        connect_websocket()
    except Exception as err:
        print(err)
        print("connect failed")