Add method to handle formatting of IPv6 in URLs

jupyterhub/objects.py

@@ -12,6 +12,7 @@ from . import orm
 from .traitlets import URLPrefix
 from .utils import (
     can_connect,
+    fmt_ip_url,
     make_ssl_context,
     random_port,
     url_path_join,
@@ -49,11 +50,8 @@ class Server(HasTraits):
         Never used in APIs, only logging,
         since it can be non-connectable value, such as '', meaning all interfaces.
         """
-        ip = self.ip
-        if ":" in ip:
-            ip = f"[{ip}]"
-        if ip in {'', '0.0.0.0', '[::]'}:
-            return self.url.replace(self._connect_ip, self.ip or '*', 1)
+        if self.ip in {'', '0.0.0.0', '::'}:
+            return self.url.replace(self._connect_ip, fmt_ip_url(self.ip) or '*', 1)
         return self.url
 
     @observe('bind_url')
@@ -219,5 +217,4 @@ class Hub(Server):
         return url_path_join(self.url, 'api')
 
     def __repr__(self):
-        ip = f"[{self.ip}]" if ":" in self.ip else self.ip
-        return f"<{self.__class__.__name__} {ip}:{self.port}>"
+        return f"<{self.__class__.__name__} {fmt_ip_url(self.ip)}:{self.port}>"

jupyterhub/orm.py

@@ -46,7 +46,7 @@ from sqlalchemy.pool import StaticPool
 from sqlalchemy.types import LargeBinary, Text, TypeDecorator
 from tornado.log import app_log
 
-from .utils import compare_token, hash_token, new_token, random_port, utcnow
+from .utils import compare_token, fmt_ip_url, hash_token, new_token, random_port, utcnow
 
 # top-level variable for easier mocking in tests
 utcnow = partial(utcnow, with_tz=False)
@@ -157,8 +157,7 @@ class Server(Base):
     spawner = relationship("Spawner", back_populates="server", uselist=False)
 
     def __repr__(self):
-        ip = f"[{self.ip}]" if ":" in self.ip else self.ip
-        return f"<Server({ip}:{self.port})>"
+        return f"<Server({fmt_ip_url(self.ip)}:{self.port})>"
 
 
 # lots of things have roles

jupyterhub/spawner.py

@@ -48,6 +48,7 @@ from .traitlets import ByteSpecification, Callable, Command
 from .utils import (
     AnyTimeoutError,
     exponential_backoff,
+    fmt_ip_url,
     maybe_future,
     random_port,
     recursive_update,
@@ -1107,8 +1108,7 @@ class Spawner(LoggingConfigurable):
             base_url = '/'
 
         proto = 'https' if self.internal_ssl else 'http'
-        ip = f"[{self.ip}]" if ":" in self.ip else self.ip
-        bind_url = f"{proto}://{ip}:{self.port}{base_url}"
+        bind_url = f"{proto}://{fmt_ip_url(self.ip)}:{self.port}{base_url}"
         env["JUPYTERHUB_SERVICE_URL"] = bind_url
 
         # the public URLs of this server and the Hub

jupyterhub/utils.py

@@ -273,7 +273,7 @@ async def wait_for_server(ip, port, timeout=10):
         ip = '127.0.0.1'
     elif ip == "::":
         ip = "::1"
-    display_ip = f"[{ip}]" if ":" in ip else ip
+    display_ip = fmt_ip_url(ip)
     app_log.debug("Waiting %ss for server at %s:%s", timeout, display_ip, port)
     tic = time.perf_counter()
     await exponential_backoff(
@@ -967,3 +967,13 @@ def recursive_update(target, new):
 
         else:
             target[k] = v
+
+
+def fmt_ip_url(ip):
+    """
+    Format an IP for use in URLs. IPv6 is wrapped with [], everything else is
+    unchanged
+    """
+    if ":" in ip:
+        return f"[{ip}]"
+    return ip