Allow to access external server IP via https. (streamlit#7712)

Fallback to HTTPS endpoint call to check external IP if HTTP call failed.

---------

Co-authored-by: Lars Hillebrand <lars.patrick.hillebrand@iais.fraunhofer.de>
Co-authored-by: Karen Javadyan <kajarenc@gmail.com>

lib/streamlit/net_util.py

@@ -22,8 +22,9 @@
 
 LOGGER = get_logger(__name__)
 
-# URL for checking the current machine's external IP address.
+# URLs for checking the current machine's external IP address.
 _AWS_CHECK_IP: Final = "http://checkip.amazonaws.com"
+_AWS_CHECK_IP_HTTPS: Final = "https://checkip.amazonaws.com"
 
 _external_ip: Optional[str] = None
 _internal_ip: Optional[str] = None
@@ -45,6 +46,9 @@ def get_external_ip() -> Optional[str]:
 
     response = _make_blocking_http_get(_AWS_CHECK_IP, timeout=5)
 
+    if response is None:
+        response = _make_blocking_http_get(_AWS_CHECK_IP_HTTPS, timeout=5)
+
     if _looks_like_an_ip_adress(response):
         _external_ip = response
     else:

lib/tests/streamlit/net_util_test.py

@@ -37,6 +37,20 @@ def test_get_external_ip(self):
             m.get(net_util._AWS_CHECK_IP, exc=requests.exceptions.ConnectTimeout)
             self.assertEqual(None, net_util.get_external_ip())
 
+    def test_get_external_ip_use_http_by_default(self):
+        with requests_mock.mock() as m:
+            m.get(net_util._AWS_CHECK_IP, text="1.2.3.4")
+            m.get(net_util._AWS_CHECK_IP_HTTPS, text="5.6.7.8")
+            self.assertEqual("1.2.3.4", net_util.get_external_ip())
+            self.assertEqual(m.call_count, 1)
+
+    def test_get_external_ip_https_if_http_fails(self):
+        with requests_mock.mock() as m:
+            m.get(net_util._AWS_CHECK_IP, exc=requests.exceptions.ConnectTimeout)
+            m.get(net_util._AWS_CHECK_IP_HTTPS, text="5.6.7.8")
+            self.assertEqual("5.6.7.8", net_util.get_external_ip())
+            self.assertEqual(m.call_count, 2)
+
     def test_get_external_ip_html(self):
         # This tests the case where the external URL returns a web page.
         # https://github.com/streamlit/streamlit/issues/554#issuecomment-604847244