Force using IPv4 when the machine supports IPv6 networks

Instagram seems to be ignoring connections coming from IPv6 networks, and
the scraper does not run when running on machines with IPv6 support. This
commit makes ensures that the scraper is using IPv4 connections.

instagram_scraper/app.py

@@ -13,6 +13,7 @@
 import os
 import pickle
 import re
+import socket
 import sys
 import textwrap
 import time
@@ -26,6 +27,7 @@
 import threading
 import concurrent.futures
 import requests
+import requests.packages.urllib3.util.connection as urllib3_connection
 import tqdm
 
 from instagram_scraper.constants import *
@@ -52,8 +54,14 @@ def write(self, x):
     def flush(self):
         return getattr(self.file, 'flush', lambda: None)()
 
+def allowed_gai_family():
+    family = socket.AF_INET  # force IPv4
+    return family
+
 original_stdout, original_stderr = sys.stdout, sys.stderr
 sys.stdout, sys.stderr = map(LockedStream, (sys.stdout, sys.stderr))
+# Force using IPv4 connections, when the machine where this code runs uses IPv6
+urllib3_connection.allowed_gai_family = allowed_gai_family
 
 def threaded_input(prompt):
     with input_lock: