Now, you may execute your recipe by going to the folder, RequestsThrottler-0.1.0/requests_throttler.

$ cd RequestsThrottler-0.1.0/requests_throttler

Make sure to give the full addresses as the command-line argument. For example, provide http://cnn.com. Not cnn.com. Otherwise, you will receive an error message similar to the one shown following:

requests.exceptions.MissingSchema: Invalid URL 'cnn.com': No schema supplied. Perhaps you meant http://cnn.com?

Run the recipe using the following command:

$  python 11_10_requests_throttling.py --address="http://cnn.com"
^[[1~[Thread=MainThread - 2017-07-29 19:34:08,897 - INFO]: Starting base throttler 'base-throttler'...
[Thread=MainThread - 2017-07-29 19:34:08,897 - INFO]: Submitting request to base throttler (url: http://cnn.com)...
[Thread=Thread-1 - 2017-07-29 19:34:08,897 - INFO]: Starting main loop...
[Thread=MainThread - 2017-07-29 19:34:08,900 - INFO]: Submitting request to base throttler (url: http://cnn.com)...
[Thread=Thread-1 - 2017-07-29 19:34:08,900 - INFO]: Sending request (url: http://cnn.com/)...
[Thread=MainThread - 2017-07-29 19:34:08,900 - INFO]: Submitting request to base throttler (url: http://cnn.com)...
[Thread=MainThread - 2017-07-29 19:34:08,901 - INFO]: Submitting request to base throttler (url: http://cnn.com)...
[Thread=MainThread - 2017-07-29 19:34:08,901 - INFO]: Submitting request to base throttler (url: http://cnn.com)...
.............
[Thread=Thread-1 - 2017-07-29 19:34:09,184 - INFO]: Request sent! (url: http://cnn.com/)
[Thread=Thread-1 - 2017-07-29 19:34:09,184 - INFO]: Sending request (url: http://cnn.com/)...
<Response [200]>
[Thread=Thread-1 - 2017-07-29 19:34:09,343 - INFO]: Request sent! (url: http://www.cnn.com/)
<Response [200]>
[Thread=Thread-1 - 2017-07-29 19:34:10,401 - INFO]: Sending request (url: http://cnn.com/)...
[Thread=Thread-1 - 2017-07-29 19:34:10,545 - INFO]: Request sent! (url: http://www.cnn.com/)
<Response [200]>
.......
Success: 10, Failures: 0
[Thread=Thread-1 - 2017-07-29 19:34:22,412 - INFO]: Exited from main loop.

The following screenshot shows the output of our recipe:

Listing 11.10 shows our recipe, that sends requests to the website provided as the command-line input, in a throttled manner:

#!/usr/bin/env python 
# Python Network Programming Cookbook, Second Edition
  -- Chapter - 11 
# This program is optimized for Python 2.7.12. 
# It may run on any other version with/without
  modifications. 
 
import argparse 
import requests 
from throttler.base_throttler import BaseThrottler 
 
 
def main(address): 
 
    # Throttle the requests with the BaseThrottler, delaying 1.5s. 
    bt = BaseThrottler(name='base-throttler', delay=1.5) 
 
    # Visit the address provided by the user. Complete URL only. 
    r = requests.Request(method='GET', url=address) 
 
    # 10 requests. 
    reqs = [r for i in range(0, 10)] 
 
    # Submit the requests with the required throttling. 
    with bt: 
        throttled_requests = bt.submit(reqs) 
 
    # Print the response for each of the requests. 
    for r in throttled_requests: 
        print (r.response) 
 
    # Final status of the requests. 
    print ("Success: {s}, Failures: {f}".format(s=bt.successes, 
            f=bt.failures)) 
 
 
if __name__ == '__main__': 
    parser = argparse.ArgumentParser(description=
                                'Requests Throttling') 
    parser.add_argument('--address', action="store",
    dest="address",  default='http://www.google.com') 
    given_args = parser.parse_args()  
    address = given_args.address 
    main (address) 

This recipe performs the accounting action, by making sure each request are sent only after a certain delay. Here we use BaseThrottler, this ensures that each request is started with a 1.5 second delay in between.