本篇内容主要讲解“Python中怎么使用Flask实现进度条”，感兴趣的朋友不妨来看看。本文介绍的方法操作简单快捷，实用性强。下面就让小编来带大家学习“Python中怎么使用Flask实现进度条”吧!
使用Flask实现进度条
问题描述
Python异步处理，新起一个进程返回处理进度
解决方案
使用 tqdm 和 multiprocessing.Pool
安装
pip install tqdm代码
import timeimport threadingfrom multiprocessing import Poolfrom tqdm import tqdmdef do_work(x): time.sleep(x) return xdef progress(): time.sleep(3) # 3秒后查进度 print(f'任务有: {pbar.total} 已完成:{pbar.n}')tasks = range(10)pbar = tqdm(total=len(tasks))if __name__ == '__main__': thread = threading.Thread(target=progress) thread.start() results = [] with Pool(processes=5) as pool: for result in pool.imap_unordered(do_work, tasks): results.append(result) pbar.update(1) print(results)效果
Flask
安装
pip install flaskmain.py
import timefrom multiprocessing import Poolfrom tqdm import tqdmfrom flask import Flask, make_response, jsonifyapp = Flask(__name__)def do_work(x): time.sleep(x) return xtotal = 5 # 总任务数tasks = range(total)pbar = tqdm(total=len(tasks))@app.route('/run/')def run(): """执行任务""" results = [] with Pool(processes=2) as pool: for _result in pool.imap_unordered(do_work, tasks): results.append(_result) if pbar.n >= total: pbar.n = 0 # 重置 pbar.update(1) response = make_response(jsonify(dict(results=results))) response.headers.add('Access-Control-Allow-Origin', '*') response.headers.add('Access-Control-Allow-Headers', '*') response.headers.add('Access-Control-Allow-Methods', '*') return response@app.route('/progress/')def progress(): """查看进度""" response = make_response(jsonify(dict(n=pbar.n, total=pbar.total))) response.headers.add('Access-Control-Allow-Origin', '*') response.headers.add('Access-Control-Allow-Headers', '*') response.headers.add('Access-Control-Allow-Methods', '*') return response启动（以 Windows 为例）
set FLASK_APP=mainflask run接口列表
执行任务：http://127.0.0.1:5000/run/
查看进度：http://127.0.0.1:5000/progress/
test.html
<!DOCTYPE html><html lang="zh"><head> <meta charset="UTF-8"> <title>进度条</title> <script src="https://cdn.bootcss.com/jquery/3.0.0/jquery.min.js"></script> <script src="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/3.3.7/js/bootstrap.min.js"></script> <link href="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/3.3.7/css/bootstrap.min.css" rel="external nofollow" rel="stylesheet"></head><body><button id="run">执行任务</button><br><br><div class="progress"> <div class="progress-bar" role="progressbar" aria-valuenow="1" aria-valuemin="0" aria-valuemax="100" >0.00% </div></div></body><script> function set_progress_rate(n, total) { //设置进度 var rate = (n / total * 100).toFixed(2); if (n > 0) { $(".progress-bar").attr("aria-valuenow", n); $(".progress-bar").attr("aria-valuemax", total); $(".progress-bar").text(rate + "%"); $(".progress-bar").css("width", rate + "%"); } } $("#run").click(function () { //执行任务 $.ajax({ url: "http://127.0.0.1:5000/run/", type: "GET", success: function (response) { set_progress_rate(100, 100); console.log('执行完成，结果为：' + response['results']); } }); }); setInterval(function () { //每1秒请求一次进度 $.ajax({ url: "http://127.0.0.1:5000/progress/", type: "GET", success: function (response) { console.log(response); var n = response["n"]; var total = response["total"]; set_progress_rate(n, total); } }); }, 1000);</script></html>效果
Flask使用简单异步任务
在Flask中使用简单异步任务最简洁优雅的原生实现：
from flask import Flaskfrom time import sleepfrom concurrent.futures import ThreadPoolExecutor# DOCS https://docs.python.org/3/library/concurrent.futures.html#concurrent.futures.ThreadPoolExecutorexecutor = ThreadPoolExecutor(2)app = Flask(__name__)@app.route('/jobs')def run_jobs(): executor.submit(some_long_task1) executor.submit(some_long_task2, 'hello', 123) return 'Two jobs was launched in background!'def some_long_task1(): print("Task #1 started!") sleep(10) print("Task #1 is done!")def some_long_task2(arg1, arg2): print("Task #2 started with args: %s %s!" % (arg1, arg2)) sleep(5) print("Task #2 is done!")if __name__ == '__main__': app.run()到此，相信大家对“Python中怎么使用Flask实现进度条”有了更深的了解，不妨来实际操作一番吧！这里是编程网网站，更多相关内容可以进入相关频道进行查询，关注我们，继续学习！
