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

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

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