Can I handle POST requests to Flask server in background thread?

Question

I know how to receive data from POST request in main thread:

from flask import Flask, render_template, request

app = Flask(__name__)

@app.route("/", methods=['POST'])
def parse_request():
    my_value = request.form.get('value_key')
    print(my_value)
    return render_template("index.html")

But can I do that in background thread to avoid blocking UI (rendering index.html)?

Answer 1

I'm assuming you want the html rendering and processing of your request to run concurrently. So, you can try threading in Python https://realpython.com/intro-to-python-threading/.

Let say you have a function that performs some processing on the request value, You can try this:

from threading import Thread
from flask import Flask, render_template, request


def process_value(val):
    output = val * 10
    return output

    
app = Flask(__name__)
    

@app.route("/", methods=['POST'])
def parse_request():
    my_value = request.form.get('value_key')
    req_thread = Thread(target=process_value(my_value))
    req_thread.start()
    print(my_value)
    return render_template("index.html")

Thread will allow process_value to run in the background