Support IPv6 addresses for --server-name (#3695)

* Support IPv6 addresses for --server-name

* Update changelog now that I have a PR number.

---------

Co-authored-by: freddyaboulton <alfonsoboulton@gmail.com>

CHANGELOG.md

@@ -23,7 +23,7 @@ No changes to highlight.
 
 ## Full Changelog:
 
-No changes to highlight.
+- Fixed IPv6 listening to work with bracket [::1] notation. by [@dsully](https://github.com/dsully) in [PR 3695](https://github.com/gradio-app/gradio/pull/3695)
 
 ## Contributors Shoutout:
 

gradio/networking.py

@@ -137,6 +137,14 @@ def start_server(
     else:
         path_to_local_server = "http://{}:{}/".format(url_host_name, port)
 
+    # Strip IPv6 brackets from the address if they exist.
+    # This is needed as http://[::1]:port/ is a valid browser address,
+    # but not a valid IPv6 address, so asyncio will throw an exception.
+    if server_name.startswith("[") and server_name.endswith("]"):
+        host = server_name[1:-1]
+    else:
+        host = server_name
+
     app = App.create_app(blocks)
 
     if blocks.save_to is not None:  # Used for selenium tests
@@ -144,7 +152,7 @@ def start_server(
     config = uvicorn.Config(
         app=app,
         port=port,
-        host=server_name,
+        host=host,
         log_level="warning",
         ssl_keyfile=ssl_keyfile,
         ssl_certfile=ssl_certfile,

test/test_networking.py

@@ -4,6 +4,7 @@ import os
 import urllib
 import warnings
 
+import pytest
 from fastapi.testclient import TestClient
 
 import gradio as gr
@@ -53,13 +54,17 @@ class TestInterfaceErrors:
 
 
 class TestStartServer:
-    def test_start_server(self):
+
+    # Test IPv4 and IPv6 hostnames as they would be passed from --server-name.
+    @pytest.mark.parametrize("host", ["127.0.0.1", "[::1]"])
+    def test_start_server(self, host):
         io = Interface(lambda x: x, "number", "number")
         io.favicon_path = None
         io.config = io.get_config_file()
         io.show_error = True
         io.flagging_callback.setup(gr.Number(), io.flagging_dir)
         io.auth = None
+        io.host = host
 
         port = networking.get_first_available_port(
             networking.INITIAL_PORT_VALUE,