Restore default writing of browser open redirect file, add opt-in to …

…skip (#1144)

fixes undefined

jupyter_server/serverapp.py

@@ -1573,6 +1573,10 @@ def _default_info_file(self):
         info_file = "jpserver-%s.json" % os.getpid()
         return os.path.join(self.runtime_dir, info_file)
 
+    no_browser_open_file = Bool(
+        False, help="If True, do not write redirect HTML file disk, or show in messages."
+    )
+
     browser_open_file = Unicode()
 
     @default("browser_open_file")
@@ -2815,9 +2819,11 @@ def start_app(self):
 
         self.write_server_info_file()
 
+        if not self.no_browser_open_file:
+            self.write_browser_open_files()
+
         # Handle the browser opening.
         if self.open_browser and not self.sock:
-            self.write_browser_open_files()
             self.launch_browser()
 
         if self.identity_provider.token and self.identity_provider.token_generated:
@@ -2840,17 +2846,26 @@ def start_app(self):
                     )
                 )
             else:
-                self.log.critical(
-                    "\n".join(
-                        [
-                            "\n",
+                if self.no_browser_open_file:
+                    message = [
+                        "\n",
+                        _i18n("To access the server, copy and paste one of these URLs:"),
+                        "    %s" % self.display_url,
+                    ]
+                else:
+                    message = [
+                        "\n",
+                        _i18n(
                             "To access the server, open this file in a browser:",
-                            "    %s" % urljoin("file:", pathname2url(self.browser_open_file)),
+                        ),
+                        "    %s" % urljoin("file:", pathname2url(self.browser_open_file)),
+                        _i18n(
                             "Or copy and paste one of these URLs:",
-                            "    %s" % self.display_url,
-                        ]
-                    )
-                )
+                        ),
+                        "    %s" % self.display_url,
+                    ]
+
+                self.log.critical("\n".join(message))
 
     async def _cleanup(self):
         """General cleanup of files, extensions and kernels created

tests/test_serverapp.py

@@ -18,6 +18,7 @@
     list_running_servers,
     random_ports,
 )
+from jupyter_server.utils import pathname2url, urljoin
 
 
 def test_help_output():
@@ -484,3 +485,12 @@ async def test_shutdown_no_activity(jp_serverapp):
 def test_running_server_info(jp_serverapp):
     app: ServerApp = jp_serverapp
     app.running_server_info(True)
+
+
+@pytest.mark.parametrize("should_exist", [True, False])
+def test_browser_open_files(jp_configurable_serverapp, should_exist, caplog):
+    app = jp_configurable_serverapp(no_browser_open_file=not should_exist)
+    assert os.path.exists(app.browser_open_file) == should_exist
+    url = urljoin("file:", pathname2url(app.browser_open_file))
+    url_messages = [rec.message for rec in caplog.records if url in rec.message]
+    assert url_messages if should_exist else not url_messages