app.py

from flask import Flask, request
import threading
import time

app = Flask(__name__)

# Mock database storing user data
users = {
    '1': {'email': 'user1@example.com'},
    '2': {'email': 'user2@example.com'}
}

# Shared variable for email updates
temporary_email_storage = ""

@app.route('/change_email/<user_id>', methods=['POST'])
def change_email(user_id):
    global temporary_email_storage
    new_email = request.form['email']
    print(f"Received request to change email for user {user_id} to {new_email}")

    # Store the email in a shared variable
    temporary_email_storage = new_email
    
    # Simulate a delay to enhance the chance of race conditions
    time.sleep(1)

    # Check if the user exists
    if user_id in users:
        # Update the email from the shared variable
        users[user_id]['email'] = temporary_email_storage
        print(f"Email for user {user_id} changed to {temporary_email_storage}")
        return f"Email changed to {temporary_email_storage} for user {user_id}", 200
    else:
        return "User not found", 404

if __name__ == '__main__':
    app.run(debug=True, threaded=True)