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 time import threading from multiprocessing import pool from tqdm import tqdm def do_work(x): time.sleep(x) return x def 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 flask
main.py
import time from multiprocessing import pool from tqdm import tqdm from flask import flask, make_response, jsonify app = flask(__name__) def do_work(x): time.sleep(x) return x total = 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=main flask run
接口列表
- 执行任务：https://127.0.0.1:5000/run/
- 查看进度：https://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" style="width: 10%">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: "https://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: "https://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 flask from time import sleep from concurrent.futures import threadpoolexecutor # docs https://docs.python.org/3/library/concurrent.futures.html#concurrent.futures.threadpoolexecutor executor = 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()
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