add no_proxy support to python client (#10648)

* add no_proxy support to python client

* add unittest for no_proxy supporting, python client

* update samples for no_proxy supporting, python client

* fix input parameter in samples/openapi3/.../tests_manual/test_extra_pool_config_options.py

* re-implement no_proxy support to python client according to PR conversation #10648

* re-update samples for no_proxy supporting, python client

samples/openapi3/client/features/dynamic-servers/python/dynamic_servers/configuration.py

@@ -179,6 +179,9 @@ class Configuration(object):
         self.proxy = None
         """Proxy URL
         """
+        self.no_proxy = None
+        """bypass proxy for host in the no_proxy list.
+        """
         self.proxy_headers = None
         """Proxy headers
         """

samples/openapi3/client/features/dynamic-servers/python/dynamic_servers/rest.py

@@ -14,8 +14,10 @@ import logging
 import re
 import ssl
 from urllib.parse import urlencode
-
+from urllib.parse import urlparse
+from urllib.request import proxy_bypass_environment
 import urllib3
+import ipaddress
 
 from dynamic_servers.exceptions import ApiException, UnauthorizedException, ForbiddenException, NotFoundException, ServiceException, ApiValueError
 
@@ -72,7 +74,7 @@ class RESTClientObject(object):
                 maxsize = 4
 
         # https pool manager
-        if configuration.proxy:
+        if configuration.proxy and not should_bypass_proxies(configuration.host, no_proxy=configuration.no_proxy or ''):
             self.pool_manager = urllib3.ProxyManager(
                 num_pools=pools_size,
                 maxsize=maxsize,
@@ -290,3 +292,55 @@ class RESTClientObject(object):
                             _preload_content=_preload_content,
                             _request_timeout=_request_timeout,
                             body=body)
+
+# end of class RESTClientObject
+def is_ipv4(target):
+    """ Test if IPv4 address or not
+    """
+    try:
+       chk = ipaddress.IPv4Address(target)
+       return True
+    except ipaddress.AddressValueError:
+       return False
+
+def in_ipv4net(target, net):
+    """ Test if target belongs to given IPv4 network
+    """
+    try:
+        nw = ipaddress.IPv4Network(net)
+        ip = ipaddress.IPv4Address(target)
+        if ip in nw:
+            return True
+        return False
+    except ipaddress.AddressValueError:
+        return False
+    except ipaddress.NetmaskValueError:
+        return False
+
+def should_bypass_proxies(url, no_proxy=None):
+    """ Yet another requests.should_bypass_proxies
+    Test if proxies should not be used for a particular url.
+    """
+
+    parsed = urlparse(url)
+
+    # special cases
+    if parsed.hostname in [None, '']:
+        return True
+
+    # special cases
+    if no_proxy in [None , '']:
+        return False
+    if no_proxy == '*':
+        return True
+
+    no_proxy = no_proxy.lower().replace(' ','');
+    entries = (
+        host for host in no_proxy.split(',') if host
+    )
+
+    if is_ipv4(parsed.hostname):
+        for item in entries:
+           if in_ipv4net(parsed.hostname, item):
+               return True
+    return proxy_bypass_environment(parsed.hostname, {'no': no_proxy} )