python websocket 发送 sensor 数据

搞了几天，顺便把代码贴这里，需要的 python 包：

gevent，gevent-websocket，bottle，wiringpi-python

gevent 提供了支持 concurrent，以及 concurrent 下的 socket 操作。注意，引入 monkey 后，socket 就是 genvent 封装过的了，不再是系统原生 socket。

连接到 /ws 后，链接为长链接，使用 gevent.Timeout() 提供的 alarm 来周期执行 sensor 读操作，并将读到的数据发送给 client。

默认返回是一个 web client，提供了一个 textarea，将 server 发来的数据显示出来。

from bottle import route, run, request, abort, Bottle, static_file
from gevent import monkey; monkey.patch_all()
from gevent import sleep, Timeout

import wiringpi
import serial

app = Bottle()

host = '0.0.0.0'
port = 8080

SensorData = ''

fdI2c = wiringpi.wiringPiI2CSetup(0x40)
ser = serial.Serial("/dev/ttyUSB0", 9600, timeout = 0.1)

def readSensor():
    global SensorData
    
    serBuffer = ser.readline().rstrip()
    if len(serBuffer) == 0:
        serBuffer = "0";

    strength = wiringpi.wiringPiI2CReadReg16(fdI2c, 0x1c);
    position = wiringpi.wiringPiI2CReadReg16(fdI2c, 0x0c);
    angle = wiringpi.wiringPiI2CReadReg16(fdI2c, 0x0e);
    
    SensorData = serBuffer + ":" \
                 + str(strength) + ":" \
                 + str(position) + ":" \
                 + str(angle);

@app.route('/ws')
def handle_websocket():
    wsock = request.environ.get('wsgi.websocket')
    if not wsock:
        abort(400, 'Expected WebSocket request.')
    while True:
        try:
            global SensorData
            with Timeout(0.5, False) as timeout:
                message = wsock.receive()
            if not message:
                readSensor()
                message = SensorData

            wsock.send("%r" % message)

            message = u''
        except WebSocketError:
            break

@app.route('/')
def send_index():
    return """<html>
<head>
  <script type='application/javascript' src='https://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js'></script>
  <script type="text/javascript">
    var ws = new WebSocket("ws://%(host)s/ws");
    ws.onopen = function() {
        ws.send("Hello, world");
    };
    ws.onmessage = function (evt) {
        $('#chat').val($('#chat').val() + evt.data + '\\n');
    };
  </script>
</head>
<body>
<form action='#' id='chatform' method='get'>
    <textarea id='chat' cols='100' rows='20'></textarea>
</form>

</body>
</html>"""%{'host':request.headers.get('Host')}

from gevent.pywsgi import WSGIServer
from geventwebsocket.handler import WebSocketHandler
from geventwebsocket import WebSocketError

server = WSGIServer((host, port), app, handler_class=WebSocketHandler)

print "access @ http://%s:%s" % (host, port)
server.serve_forever()

来源：https://www.cnblogs.com/pied/p/11972095.html

标签

websocket

软件

gevent

WiringPi

python