Python futures demo

futures.py

import urllib.request
import concurrent.futures
import time

# Takes a url, downloads the content, then does something with it. Returns
# True if everything went fine
def process_web_request(url):
    try:
        with urllib.request.urlopen(url) as response:
            html = response.read()
            if html:
                do_something_with(html)
                return True
            else: return False
    except Exception as e:
        print("Error %s" % (e,))
        return False

def do_something_with(html):
    # Do something useful here. It won't block the main thread
    print("Got data. Doing stuff with it")
    time.sleep(5)
    print(html)
    
def main():
    executor = concurrent.futures.ThreadPoolExecutor(max_workers=2)
    # Run "process_web_request" on a background thread. You'll see dots being printed to prove
    # that other stuff carries on in the meantime
    executor.submit(process_web_request, 'https://portfolio.nimbustechnologies.co.za/api')
    # Print dots while we wait for 
    for i in range(0,15):
        time.sleep(0.5)
        print(".")
    executor.shutdown(wait=True)
    print("Done")
    
### You should see a few dots get printed, then you'll see the message that the website was fetched.
### After 5 seconds of hard work, (with more dots printed), you'll see the website content printed
if __name__ == '__main__':
    main()