Send user to custom URL

Send user to configured custom URL upon launch, instead of one constructed
from bound IP address.

Author: Roy-Orbison

jupyter_server/serverapp.py

@@ -2359,9 +2359,9 @@ def _get_urlparts(
         )
         return urlparts
 
-    @property
-    def public_url(self) -> str:
-        parts = self._get_urlparts(include_token=True)
+    def _customize_url(
+        self, parts: type[urllib.parse.ParseResult]
+    ) -> urllib.parse.ParseResult:
         # Update with custom pieces.
         if self.custom_display_url:
             # Parse custom display_url
@@ -2370,6 +2370,12 @@ def public_url(self) -> str:
             custom_updates = {key: item for key, item in custom.items() if item}
             # Update public URL parts with custom pieces.
             parts = parts._replace(**custom_updates)
+        return parts
+
+    @property
+    def public_url(self) -> str:
+        parts = self._get_urlparts(include_token=True)
+        parts = self._customize_url(parts)
         return parts.geturl()
 
     @property
@@ -2394,6 +2400,7 @@ def display_url(self) -> str:
     @property
     def connection_url(self) -> str:
         urlparts = self._get_urlparts(path=self.base_url)
+        urlparts = self._customize_url(urlparts)
         return urlparts.geturl()
 
     def init_signal(self) -> None: