The script collects addresses of proxy servers from publicly available resources. Then it tries to connect (asynchronously) through each proxy server to the following websites: google.com, yahoo.com, ya.ru. It collects HTTP response statuses, total time of web-page downloading (throug proxy) and error messages (if error is raised). All this information is stored in proxy.json file.

    {
     'proxies': [<item1>, <item2>, ..., <itemN>]
     'date': <date of creation, utc>
    }

Each item<n> has the following structure (example):

    {
    "ip": xxx.xxx.xxx.xxx,
    "port": xxxx,
    "google_error" : "no",
    "yahoo_error"  : "no",
    "yandex_error" : "unknown error",
    "google_total_time" : 2900,
    "yahoo_total_time" : 1900,
    "yandex_total_time" : None,
    "google_status" : 200,
    "yahoo_status"  : 200,
    "yandex_status" : 503,
    }

• *_total_time values are given in milliseconds; each value representes total time (including connection) required to download html-content (through proxy) from either 'google.com', 'yahoo.com' or 'ya.ru'.
• *_error are attributes which represent the error messages raised during connecting to the website through proxy;
• *_status are HTTP status codes;
• ip proxy server's IP address;
• port proxy server's port;

The list of proxy servers is available as json-file through the link:

https://raw.githubusercontent.com/scidam/proxy-list/master/proxy.json

import json
from urllib.request import urlopen

json_url = "https://raw.githubusercontent.com/scidam/proxy-list/master/proxy.json"

with urlopen("json_url") as url:
    json_proxies = json.loads(url.read().decode('utf-8'))

# use json_proxies
print("The total number of proxies: ", len(json_proxies['proxies']))