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This article mainly explains "how to use Flask to achieve the progress bar in Python". Interested friends may wish to have a look. The method introduced in this paper is simple, fast and practical. Now let the editor take you to learn "how to use Flask in Python to achieve progress bar"!

Using Flask to implement the problem description of progress bar

Python asynchronous processing, and a new process returns the processing progress

Solution

Using tqdm and multiprocessing.Pool

Installation

Pip install tqdm

Code

Import timeimport threadingfrom multiprocessing import Poolfrom tqdm import tqdmdef do_work (x): time.sleep (x) return xdef progress (): time.sleep (3) # check the progress print (f 'task: {pbar.total} completed: {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)

Effect.

Flask

Installation

Pip install flask

Main.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 # Total tasks tasks = range (total) pbar = tqdm (total=len (tasks)) @ app.route ('/ run/') def run (): "" execute tasks "" 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 # reset 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 (): "View progress" 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

Start (take Windows as an example)

Set FLASK_APP=mainflask run

Interface list

Perform Task: http://127.0.0.1:5000/run/

Check progress: http://127.0.0.1:5000/progress/

Test.html

Progress bar executes tasks

0.005% function set_progress_rate (n, total) {/ / set progress 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 () {/ / execute task $.ajax ({url: "http://127.0.0.1:5000/run/", type:" GET ", success: function (response) {set_progress_rate (100,100) Console.log ('execution completed, the result is:' + response ['results']);});}) SetInterval (function () {/ / request progress $.ajax every second ({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)

Effect.

Flask uses simple asynchronous tasks

Use the most concise and elegant native implementation of simple asynchronous tasks in Flask:

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 backgroundconstrucdef 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 () so far, I believe you have a better understanding of "how to use Flask to implement the progress bar in Python" You might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

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