CODEWITHSUNDEEP
pythonmultithreadingflask
Johhny
Johhny

Reputation: 35

Flask using thread to run code after/alognside return

I am trying to run code after I return my template in flask

Here is sample code

@app.route("/hello")
def Hello():
    thread = threading.Thread(target=long_running_task)
    thread.start()
    return 'hello'

def long_running_task():
    time.sleep(5)
    return redirect("/goodbye")

Is this possible? Why when this code is ran it does not work as intended? /hello should load, then after 5 seconds it should redirect, but it never redirects and I believe the thread is never ran.

Upvotes: 1

Views: 2162

Answers (1)

ilias-sp
ilias-sp

Reputation: 6705

it does work, but since in your Hello function you return 'Hello' after the thread start, the return redirect("/goodbye") never makes it to the browser. But the processing in the background works, you can add some print statements in the long_running_task code and see the flask console for yourself:

@app.route("/hello")
def Hello():
    thread = threading.Thread(target=long_running_task)
    thread.start()
    return 'hello'

def long_running_task():
    print("long task started")
    time.sleep(5)
    print("long task ended")
    return redirect("/goodbye")

Upvotes: 3

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