这篇文章主要讲解了python轮询机制怎么控制led，内容清晰明了，对此有兴趣的小伙伴可以学习一下，相信大家阅读完之后会有帮助。

我就废话不多说了，大家还是直接看代码吧！

# -*- coding:utf-8 -*- # File: ceshitianqi import urllib2import jsonimport timeimport datetimeimport serial import randomimport osimport sys APIKEY = 'ZPdLyl***=' #改成你的APIKEYser=serial.Serial("/dev/ttyUSB2",9600,timeout=1) def read(key): ser.write(key) print("output:"+key) time.sleep(1) response = ser.readall() print(response) print(type(response)) return response def http_put(key): val = read(key) #获取Arduino的数据 CurTime = datetime.datetime.now() url='http://api.heclouds.com/devices/**1/datapoints' #values={'datastreams':[{"id":"temp","datapoints":[{"at":CurTime.isoformat(),"value":val}]}]} print(type(val)) if key== "a" : values={'datastreams':[{"id":"humidity","datapoints":[{"at":CurTime.isoformat(),"value":val}]}]} if key== "b" : values={'datastreams':[{"id":"temperature","datapoints":[{"at":CurTime.isoformat(),"value":val}]}]} jdata = json.dumps(values) # 对数据进行JSON格式化编码 #打印json内容 print jdata request = urllib2.Request(url, jdata) request.add_header('api-key', APIKEY) request.get_method = lambda:'POST' # 设置HTTP的访问方式 request = urllib2.urlopen(request) return request.read() str = ("a","b")while True:for i in str: f = open('1.txt')e = f.read()if e == "1\n":ser.write("c")if e == "0\n":ser.write("d") f.close() resp = http_put(i) time.sleep(2)

轮询1.txt

1则点亮

0则关闭

补充知识：python笔记(轮询、长轮询)

一、轮询

views.py

from flask import Flask,render_template,request,jsonifyapp = Flask(__name__)USERS = { '1':{'name':'贝贝','count':1}, '2':{'name':'小东北','count':0}, '3':{'name':'何伟明','count':0},}@app.route('/user/list')def user_list(): import time return render_template('user_list.html',users=USERS)@app.route('/vote',methods=['POST'])def vote(): uid = request.form.get('uid') USERS[uid]['count'] += 1 return "投票成功"@app.route('/get/vote',methods=['GET'])def get_vote(): return jsonify(USERS)if __name__ == '__main__': app.run(threaded=True)

html

<!DOCTYPE html><html lang="zh-CN"><head> <meta charset="UTF-8"> <title>Title</title> <meta name="viewport" content="width=device-width, initial-scale=1"> <style> li{ cursor: pointer; } </style></head><body> <ul id="userList"> {% for key,val in users.items() %} <li uid="{{key}}">{{val.name}} ({{val.count}})</li> {% endfor %} </ul> <script src="https://cdn.bootcss.com/jquery/3.3.0/jquery.min.js"></script> <script> $(function () { $('#userList').on('dblclick','li',function () { var uid = $(this).attr('uid'); $.ajax({ url:'/vote', type:'POST', data:{uid:uid}, success:function (arg) { console.log(arg); } }) }); }); /* 获取投票信息 */ function get_vote() { $.ajax({ url:'/get/vote', type:"GET", dataType:'JSON', success:function (arg) { $('#userList').empty(); $.each(arg,function (k,v) { var li = document.createElement('li'); li.setAttribute('uid',k); li.innerText = v.name + "(" + v.count + ')' ; $('#userList').append(li); }) } }) } setInterval(get_vote,3000); </script></body></html>

二、长轮询

views.py

from flask import Flask,render_template,request,jsonify,sessionimport uuidimport queueapp = Flask(__name__)app.secret_key = 'asdfasdfasd'USERS = { '1':{'name':'贝贝','count':1}, '2':{'name':'小东北','count':0}, '3':{'name':'何伟明','count':0},}QUEQUE_DICT = {}@app.route('/user/list')def user_list(): user_uuid = str(uuid.uuid4()) QUEQUE_DICT[user_uuid] = queue.Queue() session['current_user_uuid'] = user_uuid return render_template('user_list.html',users=USERS)@app.route('/vote',methods=['POST'])def vote(): uid = request.form.get('uid') USERS[uid]['count'] += 1 for q in QUEQUE_DICT.values(): q.put(USERS) return "投票成功"@app.route('/get/vote',methods=['GET'])def get_vote(): user_uuid = session['current_user_uuid'] q = QUEQUE_DICT[user_uuid] ret = {'status':True,'data':None} try: users = q.get(timeout=5) ret['data'] = users except queue.Empty: ret['status'] = False return jsonify(ret)if __name__ == '__main__': app.run(threaded=True)

html

<!DOCTYPE html><html lang="zh-CN"><head> <meta charset="UTF-8"> <title>Title</title> <meta name="viewport" content="width=device-width, initial-scale=1"> <style> li{ cursor: pointer; } </style></head><body> <ul id="userList"> {% for key,val in users.items() %} <li uid="{{key}}">{{val.name}} ({{val.count}})</li> {% endfor %} </ul> <script src="https://cdn.bootcss.com/jquery/3.3.0/jquery.min.js"></script> <script> $(function () { $('#userList').on('click','li',function () { var uid = $(this).attr('uid'); $.ajax({ url:'/vote', type:'POST', data:{uid:uid}, success:function (arg) { console.log(arg); } }) }); get_vote(); }); /* 获取投票信息 */ function get_vote() { $.ajax({ url:'/get/vote', type:"GET", dataType:'JSON', success:function (arg) { if(arg.status){ $('#userList').empty(); $.each(arg.data,function (k,v) { var li = document.createElement('li'); li.setAttribute('uid',k); li.innerText = v.name + "(" + v.count + ')' ; $('#userList').append(li); }) } get_vote(); } }) } </script></body></html>

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