Python异步处理返回进度——使用Flask实现进度条-偶像资源网

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：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\"
         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: \"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 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()

以上为个人经验，希望能给大家一个参考，也希望大家多多支持。

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