Server extensions dict,

and formatted output

notebook/nbextensions.py

@@ -604,7 +604,8 @@ class ListNBExtensionsApp(BaseNBExtensionApp):
                     self.log.info('  {} section'.format(section))
                     
                     load_extensions = data['load_extensions']
-                    [self.log.info('   {1} {0}'.format(x, GREEN_CHECK if load_extensions[x] else RED_EX)) for x in load_extensions]
+                    for x in load_extensions:
+                        self.log.info('   {1} {0}'.format(x, GREEN_CHECK if load_extensions[x] else RED_EX))
     
     def start(self):
         self.list_nbextensions()

notebook/notebookapp.py

@@ -823,9 +823,18 @@ class NotebookApp(JupyterApp):
         self.config.FileContentsManager.root_dir = new
         self.config.MappingKernelManager.root_dir = new
 
+    # TODO: Remove me in notebook 5.0
     server_extensions = List(Unicode(), config=True,
-        help=("Python modules to load as notebook server extensions. "
-              "This is an experimental API, and may change in future releases.")
+        help=("DEPRECATED use the nbserver_extensions dict instead")
+    )
+    def _server_extensions_changed(self, name, old, new):
+        self.log.warning("server_extensions is deprecated, use nbserver_extensions")
+        self.server_extensions = new
+        
+    nbserver_extensions = Dict({}, config=True,
+        help=("Dict of Python modules to load as notebook server extensions."
+              "Entry values can be used to enable and disable the loading of"
+              "the extensions.")
     )
 
     reraise_server_extension_failures = Bool(
@@ -1064,17 +1073,26 @@ class NotebookApp(JupyterApp):
         
         The extension API is experimental, and may change in future releases.
         """
+        
+        # TODO: Remove me in notebook 5.0
         for modulename in self.server_extensions:
-            try:
-                mod = importlib.import_module(modulename)
-                func = getattr(mod, 'load_jupyter_server_extension', None)
-                if func is not None:
-                    func(self)
-            except Exception:
-                if self.reraise_server_extension_failures:
-                    raise
-                self.log.warning("Error loading server extension %s", modulename,
-                              exc_info=True)
+            # Don't override disable state of the extension if it already exist
+            # in the new traitlet
+            if not modulename in self.nbserver_extensions:
+                self.nbserver_extensions[modulename] = True
+        
+        for modulename in self.nbserver_extensions:
+            if self.nbserver_extensions[modulename]:
+                try:
+                    mod = importlib.import_module(modulename)
+                    func = getattr(mod, 'load_jupyter_server_extension', None)
+                    if func is not None:
+                        func(self)
+                except Exception:
+                    if self.reraise_server_extension_failures:
+                        raise
+                    self.log.warning("Error loading server extension %s", modulename,
+                                  exc_info=True)
     
     @catch_config_error
     def initialize(self, argv=None):

notebook/serverextensions.py

@@ -76,18 +76,18 @@ class ToggleServerExtensionApp(ToggleNBExtensionApp):
         cfg = cm.get("jupyter_notebook_config")
         server_extensions = (
             cfg.setdefault("NotebookApp", {})
-            .setdefault("server_extensions", [])
+            .setdefault("nbserver_extensions", {})
         )
         if self._toggle_value:
-            if require not in server_extensions:
-                server_extensions.append(require)
+            server_extensions[require] = True
+        else:
+            if self._toggle_value is None:
+                if require not in server_extensions:
+                    print("server extension not installed")
+                else:
+                    server_extensions[require] = not server_extensions[require]
             else:
-                print("server extension already enabled")
-        elif self._toggle_value is None:
-            if require not in server_extensions:
-                print("server extension already disabled")
-            else:
-                server_extensions.remove(require)
+                server_extensions[require] = False
         cm.update("jupyter_notebook_config", cfg)
 
     def toggle_server_extension_python(self, package):
@@ -121,7 +121,7 @@ class DisableServerExtensionApp(ToggleServerExtensionApp):
 
     name = "jupyter serverextension disable"
     description = "Disable an serverextension using frontend configuration files."
-    _toggle_value = None
+    _toggle_value = False
 
 
 class ListServerExtensionsApp(BaseNBExtensionApp):
@@ -131,6 +131,9 @@ class ListServerExtensionsApp(BaseNBExtensionApp):
     description = "List all server extensions known by the configuration system"
 
     def list_server_extensions(self):
+        GREEN_CHECK = '\033[92m✔️\033[0m'
+        RED_EX = '\033[91m❌\033[0m'
+        
         config_dirs = jupyter_config_path()
         for config_dir in config_dirs:
             self.log.info('config dir: {}'.format(config_dir))
@@ -138,10 +141,10 @@ class ListServerExtensionsApp(BaseNBExtensionApp):
             data = cm.get("jupyter_notebook_config")
             server_extensions = (
                 data.setdefault("NotebookApp", {})
-                .setdefault("server_extensions", [])
+                .setdefault("nbserver_extensions", {})
             )
-            if server_extensions:
-                self.log.info('    {}'.format(server_extensions))
+            for x in server_extensions:
+                self.log.info('    {1} {0}'.format(x, GREEN_CHECK if server_extensions[x] else RED_EX))
 
     def start(self):
         self.list_server_extensions()