From 3d4cc154d476c78cf51f420d8690e41566c0823a Mon Sep 17 00:00:00 2001
From: Vadym Kaidalov <vadym.kaidalov@refinitiv.com>
Date: Mon, 26 Apr 2021 14:28:14 +0300
Subject: [PATCH 1/3] Add `bandwidthSaveMode` to `ServiceManager`, use it in
 `hub-extension`

---
 packages/docmanager/src/manager.ts           |  3 +-
 packages/docmanager/src/savehandler.ts       | 13 ++++++-
 packages/docmanager/test/savehandler.spec.ts |  2 +-
 packages/filebrowser/src/model.ts            |  4 +-
 packages/hub-extension/src/index.ts          |  2 +
 packages/services/src/kernel/manager.ts      |  2 +-
 packages/services/src/kernelspec/manager.ts  |  2 +-
 packages/services/src/manager.ts             | 41 ++++++++++++++++++--
 packages/services/src/session/manager.ts     |  2 +-
 packages/services/src/terminal/manager.ts    |  2 +-
 10 files changed, 62 insertions(+), 11 deletions(-)

diff --git a/packages/docmanager/src/manager.ts b/packages/docmanager/src/manager.ts
index cfa9387c804a..242e91e0a509 100644
--- a/packages/docmanager/src/manager.ts
+++ b/packages/docmanager/src/manager.ts
@@ -485,7 +485,8 @@ export class DocumentManager implements IDocumentManager {
     });
     const handler = new SaveHandler({
       context,
-      saveInterval: this.autosaveInterval
+      saveInterval: this.autosaveInterval,
+      services: this.services
     });
     Private.saveHandlerProperty.set(context, handler);
     void context.ready.then(() => {
diff --git a/packages/docmanager/src/savehandler.ts b/packages/docmanager/src/savehandler.ts
index 25eb3792089f..be3119b95d1d 100644
--- a/packages/docmanager/src/savehandler.ts
+++ b/packages/docmanager/src/savehandler.ts
@@ -5,6 +5,8 @@ import { IDisposable } from '@lumino/disposable';
 
 import { Signal } from '@lumino/signaling';
 
+import { ServiceManager } from '@jupyterlab/services';
+
 import { DocumentRegistry } from '@jupyterlab/docregistry';
 
 /**
@@ -19,6 +21,7 @@ export class SaveHandler implements IDisposable {
    */
   constructor(options: SaveHandler.IOptions) {
     this._context = options.context;
+    this._services = options.services;
     const interval = options.saveInterval || 120;
     this._minInterval = interval * 1000;
     this._interval = this._minInterval;
@@ -91,7 +94,9 @@ export class SaveHandler implements IDisposable {
       return;
     }
     this._autosaveTimer = window.setTimeout(() => {
-      this._save();
+      if (!this._services.bandwidthSaveMode) {
+        this._save();
+      }
     }, this._interval);
   }
 
@@ -146,6 +151,7 @@ export class SaveHandler implements IDisposable {
   private _minInterval = -1;
   private _interval = -1;
   private _context: DocumentRegistry.Context;
+  private _services: ServiceManager.IManager;
   private _isActive = false;
   private _inDialog = false;
   private _isDisposed = false;
@@ -169,5 +175,10 @@ export namespace SaveHandler {
      * The minimum save interval in seconds (default is two minutes).
      */
     saveInterval?: number;
+
+    /**
+     * A service manager instance.
+     */
+    services: ServiceManager.IManager;
   }
 }
diff --git a/packages/docmanager/test/savehandler.spec.ts b/packages/docmanager/test/savehandler.spec.ts
index e18985332be1..2ff90dedd30d 100644
--- a/packages/docmanager/test/savehandler.spec.ts
+++ b/packages/docmanager/test/savehandler.spec.ts
@@ -38,7 +38,7 @@ describe('docregistry/savehandler', () => {
       factory,
       path: UUID.uuid4() + '.txt'
     });
-    handler = new SaveHandler({ context });
+    handler = new SaveHandler({ context, services: manager });
     return context.initialize(true);
   });
 
diff --git a/packages/filebrowser/src/model.ts b/packages/filebrowser/src/model.ts
index 1d1d7454e527..695e91cc82f9 100644
--- a/packages/filebrowser/src/model.ts
+++ b/packages/filebrowser/src/model.ts
@@ -113,7 +113,9 @@ export class FileBrowserModel implements IDisposable {
         backoff: true,
         max: 300 * 1000
       },
-      standby: 'when-hidden'
+      standby: () => {
+        return services.bandwidthSaveMode || 'when-hidden';
+      }
     });
   }
 
diff --git a/packages/hub-extension/src/index.ts b/packages/hub-extension/src/index.ts
index 9f777fbb301d..15e4eabaaaf6 100644
--- a/packages/hub-extension/src/index.ts
+++ b/packages/hub-extension/src/index.ts
@@ -153,6 +153,7 @@ const connectionlost: JupyterFrontEndPlugin<IConnectionLost> = {
         return;
       }
       showingError = true;
+      manager.bandwidthSaveMode = true;
       const result = await showDialog({
         title: trans.__('Server unavailable or unreachable'),
         body: trans.__(
@@ -164,6 +165,7 @@ const connectionlost: JupyterFrontEndPlugin<IConnectionLost> = {
           Dialog.cancelButton({ label: trans.__('Dismiss') })
         ]
       });
+      manager.bandwidthSaveMode = false;
       showingError = false;
       if (result.button.accept) {
         await app.commands.execute(CommandIDs.restart);
diff --git a/packages/services/src/kernel/manager.ts b/packages/services/src/kernel/manager.ts
index 2f3c0702de9f..97516b13e7ce 100644
--- a/packages/services/src/kernel/manager.ts
+++ b/packages/services/src/kernel/manager.ts
@@ -337,6 +337,6 @@ export namespace KernelManager {
     /**
      * When the manager stops polling the API. Defaults to `when-hidden`.
      */
-    standby?: Poll.Standby;
+    standby?: Poll.Standby | (() => boolean | Poll.Standby);
   }
 }
diff --git a/packages/services/src/kernelspec/manager.ts b/packages/services/src/kernelspec/manager.ts
index 717a771f2bf6..9ce1f92b40b8 100644
--- a/packages/services/src/kernelspec/manager.ts
+++ b/packages/services/src/kernelspec/manager.ts
@@ -147,6 +147,6 @@ export namespace KernelSpecManager {
     /**
      * When the manager stops polling the API. Defaults to `when-hidden`.
      */
-    standby?: Poll.Standby;
+    standby?: Poll.Standby | (() => boolean | Poll.Standby);
   }
 }
diff --git a/packages/services/src/manager.ts b/packages/services/src/manager.ts
index cd4d93131f34..edc86ceb5b14 100644
--- a/packages/services/src/manager.ts
+++ b/packages/services/src/manager.ts
@@ -37,7 +37,12 @@ export class ServiceManager implements ServiceManager.IManager {
     const defaultDrive = options.defaultDrive;
     const serverSettings =
       options.serverSettings ?? ServerConnection.makeSettings();
-    const standby = options.standby ?? 'when-hidden';
+
+    const standby =
+      options.standby ??
+      (() => {
+        return this.bandwidthSaveMode || 'when-hidden';
+      });
     const normalized = { defaultDrive, serverSettings, standby };
 
     const kernelManager = new KernelManager(normalized);
@@ -158,6 +163,23 @@ export class ServiceManager implements ServiceManager.IManager {
     return this._readyPromise;
   }
 
+  /**
+   * Every periodic network polling should be paused while
+   * this is set to true. Extensions should use this value
+   * to decide whether to proceed with the polling.
+   * The extensions may also set this value to true if there is no need
+   * to fetch anything from the server backend basing on some conditions
+   * (e.g. when an error message dialog is displayed).
+   * At the same time, the extensions are responsible for setting
+   * this value back to false.
+   */
+  get bandwidthSaveMode(): boolean {
+    return this._bandwidthSaveMode;
+  }
+  set bandwidthSaveMode(value: boolean) {
+    this._bandwidthSaveMode = value;
+  }
+
   private _onConnectionFailure(sender: any, err: Error): void {
     this._connectionFailure.emit(err);
   }
@@ -166,6 +188,7 @@ export class ServiceManager implements ServiceManager.IManager {
   private _readyPromise: Promise<void>;
   private _connectionFailure = new Signal<this, Error>(this);
   private _isReady = false;
+  private _bandwidthSaveMode = false;
 }
 
 /**
@@ -235,6 +258,18 @@ export namespace ServiceManager {
      * A signal emitted when there is a connection failure with the server.
      */
     readonly connectionFailure: ISignal<IManager, Error>;
+
+    /**
+     * Every periodic network polling should be paused while
+     * this is set to true. Extensions should use this value
+     * to decide whether to proceed with the polling.
+     * The extensions may also set this value to true if there is no need
+     * to fetch anything from the server backend basing on some conditions
+     * (e.g. when an error message dialog is displayed).
+     * At the same time, the extensions are responsible for setting
+     * this value back to false.
+     */
+    bandwidthSaveMode: boolean;
   }
 
   /**
@@ -252,8 +287,8 @@ export namespace ServiceManager {
     readonly defaultDrive?: Contents.IDrive;
 
     /**
-     * When the manager stops polling the API. Defaults to `when-hidden`.
+     * When the manager stops polling the API.
      */
-    standby?: Poll.Standby;
+    standby?: Poll.Standby | (() => boolean | Poll.Standby);
   }
 }
diff --git a/packages/services/src/session/manager.ts b/packages/services/src/session/manager.ts
index 1e9d092a5516..c0b2f9aff56f 100644
--- a/packages/services/src/session/manager.ts
+++ b/packages/services/src/session/manager.ts
@@ -355,7 +355,7 @@ export namespace SessionManager {
     /**
      * When the manager stops polling the API. Defaults to `when-hidden`.
      */
-    standby?: Poll.Standby;
+    standby?: Poll.Standby | (() => boolean | Poll.Standby);
 
     /**
      * Kernel Manager
diff --git a/packages/services/src/terminal/manager.ts b/packages/services/src/terminal/manager.ts
index 74840efe40f4..1c2dd89ba7c1 100644
--- a/packages/services/src/terminal/manager.ts
+++ b/packages/services/src/terminal/manager.ts
@@ -289,6 +289,6 @@ export namespace TerminalManager {
     /**
      * When the manager stops polling the API. Defaults to `when-hidden`.
      */
-    standby?: Poll.Standby;
+    standby?: Poll.Standby | (() => boolean | Poll.Standby);
   }
 }

From 7444026795553f7b755ffabc575682180feb5ee9 Mon Sep 17 00:00:00 2001
From: Vadym Kaidalov <vadym.kaidalov@refinitiv.com>
Date: Wed, 28 Apr 2021 16:41:10 +0300
Subject: [PATCH 2/3] Move `bandwidthSaveMode` to `JupyterLab.IInfo` of
 `@jupyterlab/application`

---
 packages/application/src/lab.ts              | 31 ++++++++++++++--
 packages/docmanager-extension/src/index.ts   | 14 +++++--
 packages/docmanager/src/manager.ts           | 13 ++++++-
 packages/docmanager/src/savehandler.ts       | 18 ++++-----
 packages/docmanager/test/savehandler.spec.ts |  2 +-
 packages/filebrowser-extension/src/index.ts  | 16 ++++++--
 packages/filebrowser/src/model.ts            |  9 +++--
 packages/hub-extension/src/index.ts          | 19 ++++++++--
 packages/services/src/manager.ts             | 39 +-------------------
 9 files changed, 95 insertions(+), 66 deletions(-)

diff --git a/packages/application/src/lab.ts b/packages/application/src/lab.ts
index eedc94feb363..b6d5f3c10b89 100644
--- a/packages/application/src/lab.ts
+++ b/packages/application/src/lab.ts
@@ -7,6 +7,8 @@ import { Base64ModelFactory } from '@jupyterlab/docregistry';
 
 import { IRenderMime } from '@jupyterlab/rendermime-interfaces';
 
+import { ServiceManager } from '@jupyterlab/services';
+
 import { Token } from '@lumino/coreutils';
 
 import { JupyterFrontEnd, JupyterFrontEndPlugin } from './frontend';
@@ -25,7 +27,17 @@ export class JupyterLab extends JupyterFrontEnd<ILabShell> {
    * Construct a new JupyterLab object.
    */
   constructor(options: JupyterLab.IOptions = { shell: new LabShell() }) {
-    super({ ...options, shell: options.shell || new LabShell() });
+    super({
+      ...options,
+      shell: options.shell || new LabShell(),
+      serviceManager:
+        options.serviceManager ||
+        new ServiceManager({
+          standby: () => {
+            return this._info.bandwidthSaveMode || 'when-hidden';
+          }
+        })
+    });
     this.restored = this.shell.restored
       .then(() => undefined)
       .catch(() => undefined);
@@ -164,7 +176,7 @@ export class JupyterLab extends JupyterFrontEnd<ILabShell> {
     });
   }
 
-  private _info: JupyterLab.IInfo;
+  private _info: JupyterLab.IInfo = JupyterLab.defaultInfo;
   private _paths: JupyterFrontEnd.IPaths;
 }
 
@@ -214,6 +226,18 @@ export namespace JupyterLab {
      * Whether files are cached on the server.
      */
     readonly filesCached: boolean;
+
+    /**
+     * Every periodic network polling should be paused while this is set
+     * to `true`. Extensions should use this value to decide whether to proceed
+     * with the polling.
+     * The extensions may also set this value to `true` if there is no need to
+     * fetch anything from the server backend basing on some conditions
+     * (e.g. when an error message dialog is displayed).
+     * At the same time, the extensions are responsible for setting this value
+     * back to `false`.
+     */
+    bandwidthSaveMode: boolean;
   }
 
   /**
@@ -224,7 +248,8 @@ export namespace JupyterLab {
     deferred: { patterns: [], matches: [] },
     disabled: { patterns: [], matches: [] },
     mimeExtensions: [],
-    filesCached: PageConfig.getOption('cacheFiles').toLowerCase() === 'true'
+    filesCached: PageConfig.getOption('cacheFiles').toLowerCase() === 'true',
+    bandwidthSaveMode: false
   };
 
   /**
diff --git a/packages/docmanager-extension/src/index.ts b/packages/docmanager-extension/src/index.ts
index 358aa0f02ff6..bdb42fee1faf 100644
--- a/packages/docmanager-extension/src/index.ts
+++ b/packages/docmanager-extension/src/index.ts
@@ -9,7 +9,8 @@ import {
   ILabShell,
   ILabStatus,
   JupyterFrontEnd,
-  JupyterFrontEndPlugin
+  JupyterFrontEndPlugin,
+  JupyterLab
 } from '@jupyterlab/application';
 
 import {
@@ -99,7 +100,8 @@ const docManagerPlugin: JupyterFrontEndPlugin<IDocumentManager> = {
     ICommandPalette,
     ILabShell,
     IMainMenu,
-    ISessionContextDialogs
+    ISessionContextDialogs,
+    JupyterLab.IInfo
   ],
   activate: (
     app: JupyterFrontEnd,
@@ -109,7 +111,8 @@ const docManagerPlugin: JupyterFrontEndPlugin<IDocumentManager> = {
     palette: ICommandPalette | null,
     labShell: ILabShell | null,
     mainMenu: IMainMenu | null,
-    sessionDialogs: ISessionContextDialogs | null
+    sessionDialogs: ISessionContextDialogs | null,
+    info: JupyterLab.IInfo | null
   ): IDocumentManager => {
     const trans = translator.load('jupyterlab');
     const manager = app.serviceManager;
@@ -147,7 +150,10 @@ const docManagerPlugin: JupyterFrontEndPlugin<IDocumentManager> = {
       when,
       setBusy: (status && (() => status.setBusy())) ?? undefined,
       sessionDialogs: sessionDialogs || undefined,
-      translator
+      translator,
+      bandwidthSaveModeCallback: () => {
+        return info?.bandwidthSaveMode || false;
+      }
     });
 
     // Register the file operations commands.
diff --git a/packages/docmanager/src/manager.ts b/packages/docmanager/src/manager.ts
index 242e91e0a509..0f85fa97c10a 100644
--- a/packages/docmanager/src/manager.ts
+++ b/packages/docmanager/src/manager.ts
@@ -49,6 +49,8 @@ export class DocumentManager implements IDocumentManager {
    */
   constructor(options: DocumentManager.IOptions) {
     this.translator = options.translator || nullTranslator;
+    this._bandwidthSaveModeCallback =
+      options.bandwidthSaveModeCallback || (() => false);
     this.registry = options.registry;
     this.services = options.manager;
     this._dialogs = options.sessionDialogs || sessionContextDialogs;
@@ -485,8 +487,8 @@ export class DocumentManager implements IDocumentManager {
     });
     const handler = new SaveHandler({
       context,
-      saveInterval: this.autosaveInterval,
-      services: this.services
+      bandwidthSaveModeCallback: this._bandwidthSaveModeCallback,
+      saveInterval: this.autosaveInterval
     });
     Private.saveHandlerProperty.set(context, handler);
     void context.ready.then(() => {
@@ -609,6 +611,7 @@ export class DocumentManager implements IDocumentManager {
   private _when: Promise<void>;
   private _setBusy: (() => IDisposable) | undefined;
   private _dialogs: ISessionContext.IDialogs;
+  private _bandwidthSaveModeCallback: () => boolean;
 }
 
 /**
@@ -653,6 +656,12 @@ export namespace DocumentManager {
      * The applicaton language translator.
      */
     translator?: ITranslator;
+
+    /**
+     * Autosaving should be paused while this callback function returns `true`.
+     * By default, it always returns `false`.
+     */
+    bandwidthSaveModeCallback?: () => boolean;
   }
 
   /**
diff --git a/packages/docmanager/src/savehandler.ts b/packages/docmanager/src/savehandler.ts
index be3119b95d1d..f44dcd125f43 100644
--- a/packages/docmanager/src/savehandler.ts
+++ b/packages/docmanager/src/savehandler.ts
@@ -5,8 +5,6 @@ import { IDisposable } from '@lumino/disposable';
 
 import { Signal } from '@lumino/signaling';
 
-import { ServiceManager } from '@jupyterlab/services';
-
 import { DocumentRegistry } from '@jupyterlab/docregistry';
 
 /**
@@ -21,7 +19,8 @@ export class SaveHandler implements IDisposable {
    */
   constructor(options: SaveHandler.IOptions) {
     this._context = options.context;
-    this._services = options.services;
+    this._bandwidthSaveModeCallback =
+      options.bandwidthSaveModeCallback || (() => false);
     const interval = options.saveInterval || 120;
     this._minInterval = interval * 1000;
     this._interval = this._minInterval;
@@ -94,7 +93,7 @@ export class SaveHandler implements IDisposable {
       return;
     }
     this._autosaveTimer = window.setTimeout(() => {
-      if (!this._services.bandwidthSaveMode) {
+      if (!this._bandwidthSaveModeCallback()) {
         this._save();
       }
     }, this._interval);
@@ -151,7 +150,7 @@ export class SaveHandler implements IDisposable {
   private _minInterval = -1;
   private _interval = -1;
   private _context: DocumentRegistry.Context;
-  private _services: ServiceManager.IManager;
+  private _bandwidthSaveModeCallback: () => boolean;
   private _isActive = false;
   private _inDialog = false;
   private _isDisposed = false;
@@ -172,13 +171,14 @@ export namespace SaveHandler {
     context: DocumentRegistry.Context;
 
     /**
-     * The minimum save interval in seconds (default is two minutes).
+     * Autosaving should be paused while this callback function returns `true`.
+     * By default, it always returns `false`.
      */
-    saveInterval?: number;
+    bandwidthSaveModeCallback?: () => boolean;
 
     /**
-     * A service manager instance.
+     * The minimum save interval in seconds (default is two minutes).
      */
-    services: ServiceManager.IManager;
+    saveInterval?: number;
   }
 }
diff --git a/packages/docmanager/test/savehandler.spec.ts b/packages/docmanager/test/savehandler.spec.ts
index 2ff90dedd30d..e18985332be1 100644
--- a/packages/docmanager/test/savehandler.spec.ts
+++ b/packages/docmanager/test/savehandler.spec.ts
@@ -38,7 +38,7 @@ describe('docregistry/savehandler', () => {
       factory,
       path: UUID.uuid4() + '.txt'
     });
-    handler = new SaveHandler({ context, services: manager });
+    handler = new SaveHandler({ context });
     return context.initialize(true);
   });
 
diff --git a/packages/filebrowser-extension/src/index.ts b/packages/filebrowser-extension/src/index.ts
index aaf5a192cc6b..3605e69f347e 100644
--- a/packages/filebrowser-extension/src/index.ts
+++ b/packages/filebrowser-extension/src/index.ts
@@ -11,7 +11,8 @@ import {
   ITreePathUpdater,
   IRouter,
   JupyterFrontEnd,
-  JupyterFrontEndPlugin
+  JupyterFrontEndPlugin,
+  JupyterLab
 } from '@jupyterlab/application';
 
 import {
@@ -253,14 +254,20 @@ const factory: JupyterFrontEndPlugin<IFileBrowserFactory> = {
   id: '@jupyterlab/filebrowser-extension:factory',
   provides: IFileBrowserFactory,
   requires: [IDocumentManager, ITranslator],
-  optional: [IStateDB, IRouter, JupyterFrontEnd.ITreeResolver],
+  optional: [
+    IStateDB,
+    IRouter,
+    JupyterFrontEnd.ITreeResolver,
+    JupyterLab.IInfo
+  ],
   activate: async (
     app: JupyterFrontEnd,
     docManager: IDocumentManager,
     translator: ITranslator,
     state: IStateDB | null,
     router: IRouter | null,
-    tree: JupyterFrontEnd.ITreeResolver | null
+    tree: JupyterFrontEnd.ITreeResolver | null,
+    info: JupyterLab.IInfo | null
   ): Promise<IFileBrowserFactory> => {
     const { commands } = app;
     const tracker = new WidgetTracker<FileBrowser>({ namespace });
@@ -274,6 +281,9 @@ const factory: JupyterFrontEndPlugin<IFileBrowserFactory> = {
         manager: docManager,
         driveName: options.driveName || '',
         refreshInterval: options.refreshInterval,
+        refreshStandby: () => {
+          return info?.bandwidthSaveMode || 'when-hidden';
+        },
         state:
           options.state === null
             ? undefined
diff --git a/packages/filebrowser/src/model.ts b/packages/filebrowser/src/model.ts
index 695e91cc82f9..f296e1f4da24 100644
--- a/packages/filebrowser/src/model.ts
+++ b/packages/filebrowser/src/model.ts
@@ -113,9 +113,7 @@ export class FileBrowserModel implements IDisposable {
         backoff: true,
         max: 300 * 1000
       },
-      standby: () => {
-        return services.bandwidthSaveMode || 'when-hidden';
-      }
+      standby: options.refreshStandby || 'when-hidden'
     });
   }
 
@@ -700,6 +698,11 @@ export namespace FileBrowserModel {
      */
     refreshInterval?: number;
 
+    /**
+     * When the model stops polling the API. Defaults to `when-hidden`.
+     */
+    refreshStandby?: Poll.Standby | (() => boolean | Poll.Standby);
+
     /**
      * An optional state database. If provided, the model will restore which
      * folder was last opened when it is restored.
diff --git a/packages/hub-extension/src/index.ts b/packages/hub-extension/src/index.ts
index 15e4eabaaaf6..c7b76b4a946f 100644
--- a/packages/hub-extension/src/index.ts
+++ b/packages/hub-extension/src/index.ts
@@ -13,7 +13,8 @@ import {
   ConnectionLost,
   IConnectionLost,
   JupyterFrontEnd,
-  JupyterFrontEndPlugin
+  JupyterFrontEndPlugin,
+  JupyterLab
 } from '@jupyterlab/application';
 
 import { URLExt } from '@jupyterlab/coreutils';
@@ -128,10 +129,12 @@ const hubExtension: JupyterFrontEndPlugin<void> = {
 const connectionlost: JupyterFrontEndPlugin<IConnectionLost> = {
   id: '@jupyterlab/apputils-extension:connectionlost',
   requires: [JupyterFrontEnd.IPaths, ITranslator],
+  optional: [JupyterLab.IInfo],
   activate: (
     app: JupyterFrontEnd,
     paths: JupyterFrontEnd.IPaths,
-    translator: ITranslator
+    translator: ITranslator,
+    info: JupyterLab.IInfo | null
   ): IConnectionLost => {
     const trans = translator.load('jupyterlab');
     const hubPrefix = paths.urls.hubPrefix || '';
@@ -152,8 +155,12 @@ const connectionlost: JupyterFrontEndPlugin<IConnectionLost> = {
       if (showingError) {
         return;
       }
+
       showingError = true;
-      manager.bandwidthSaveMode = true;
+      if (info) {
+        info.bandwidthSaveMode = true;
+      }
+
       const result = await showDialog({
         title: trans.__('Server unavailable or unreachable'),
         body: trans.__(
@@ -165,8 +172,12 @@ const connectionlost: JupyterFrontEndPlugin<IConnectionLost> = {
           Dialog.cancelButton({ label: trans.__('Dismiss') })
         ]
       });
-      manager.bandwidthSaveMode = false;
+
+      if (info) {
+        info.bandwidthSaveMode = false;
+      }
       showingError = false;
+
       if (result.button.accept) {
         await app.commands.execute(CommandIDs.restart);
       }
diff --git a/packages/services/src/manager.ts b/packages/services/src/manager.ts
index edc86ceb5b14..a328f5730e91 100644
--- a/packages/services/src/manager.ts
+++ b/packages/services/src/manager.ts
@@ -37,12 +37,7 @@ export class ServiceManager implements ServiceManager.IManager {
     const defaultDrive = options.defaultDrive;
     const serverSettings =
       options.serverSettings ?? ServerConnection.makeSettings();
-
-    const standby =
-      options.standby ??
-      (() => {
-        return this.bandwidthSaveMode || 'when-hidden';
-      });
+    const standby = options.standby ?? 'when-hidden';
     const normalized = { defaultDrive, serverSettings, standby };
 
     const kernelManager = new KernelManager(normalized);
@@ -163,23 +158,6 @@ export class ServiceManager implements ServiceManager.IManager {
     return this._readyPromise;
   }
 
-  /**
-   * Every periodic network polling should be paused while
-   * this is set to true. Extensions should use this value
-   * to decide whether to proceed with the polling.
-   * The extensions may also set this value to true if there is no need
-   * to fetch anything from the server backend basing on some conditions
-   * (e.g. when an error message dialog is displayed).
-   * At the same time, the extensions are responsible for setting
-   * this value back to false.
-   */
-  get bandwidthSaveMode(): boolean {
-    return this._bandwidthSaveMode;
-  }
-  set bandwidthSaveMode(value: boolean) {
-    this._bandwidthSaveMode = value;
-  }
-
   private _onConnectionFailure(sender: any, err: Error): void {
     this._connectionFailure.emit(err);
   }
@@ -188,7 +166,6 @@ export class ServiceManager implements ServiceManager.IManager {
   private _readyPromise: Promise<void>;
   private _connectionFailure = new Signal<this, Error>(this);
   private _isReady = false;
-  private _bandwidthSaveMode = false;
 }
 
 /**
@@ -258,18 +235,6 @@ export namespace ServiceManager {
      * A signal emitted when there is a connection failure with the server.
      */
     readonly connectionFailure: ISignal<IManager, Error>;
-
-    /**
-     * Every periodic network polling should be paused while
-     * this is set to true. Extensions should use this value
-     * to decide whether to proceed with the polling.
-     * The extensions may also set this value to true if there is no need
-     * to fetch anything from the server backend basing on some conditions
-     * (e.g. when an error message dialog is displayed).
-     * At the same time, the extensions are responsible for setting
-     * this value back to false.
-     */
-    bandwidthSaveMode: boolean;
   }
 
   /**
@@ -287,7 +252,7 @@ export namespace ServiceManager {
     readonly defaultDrive?: Contents.IDrive;
 
     /**
-     * When the manager stops polling the API.
+     * When the manager stops polling the API. Defaults to `when-hidden`.
      */
     standby?: Poll.Standby | (() => boolean | Poll.Standby);
   }

From 2775683f5ad0ff87b1c573e14e09df8decab2265 Mon Sep 17 00:00:00 2001
From: Vadym Kaidalov <vadym.kaidalov@refinitiv.com>
Date: Tue, 10 Aug 2021 22:48:44 +0300
Subject: [PATCH 3/3] Rename `bandwidthSaveMode` to `isConnected` in
 `JupyterLab.IInfo`

---
 packages/application/src/lab.ts             | 12 ++++++------
 packages/docmanager-extension/src/index.ts  |  7 +++++--
 packages/docmanager/src/manager.ts          | 13 ++++++-------
 packages/docmanager/src/savehandler.ts      | 13 ++++++-------
 packages/filebrowser-extension/src/index.ts |  5 ++++-
 packages/hub-extension/src/index.ts         |  4 ++--
 6 files changed, 29 insertions(+), 25 deletions(-)

diff --git a/packages/application/src/lab.ts b/packages/application/src/lab.ts
index aa001fdbccd1..6bf610aa9059 100644
--- a/packages/application/src/lab.ts
+++ b/packages/application/src/lab.ts
@@ -26,7 +26,7 @@ export class JupyterLab extends JupyterFrontEnd<ILabShell> {
         options.serviceManager ||
         new ServiceManager({
           standby: () => {
-            return this._info.bandwidthSaveMode || 'when-hidden';
+            return !this._info.isConnected || 'when-hidden';
           }
         })
     });
@@ -221,15 +221,15 @@ export namespace JupyterLab {
 
     /**
      * Every periodic network polling should be paused while this is set
-     * to `true`. Extensions should use this value to decide whether to proceed
+     * to `false`. Extensions should use this value to decide whether to proceed
      * with the polling.
-     * The extensions may also set this value to `true` if there is no need to
+     * The extensions may also set this value to `false` if there is no need to
      * fetch anything from the server backend basing on some conditions
      * (e.g. when an error message dialog is displayed).
      * At the same time, the extensions are responsible for setting this value
-     * back to `false`.
+     * back to `true`.
      */
-    bandwidthSaveMode: boolean;
+    isConnected: boolean;
   }
 
   /**
@@ -241,7 +241,7 @@ export namespace JupyterLab {
     disabled: { patterns: [], matches: [] },
     mimeExtensions: [],
     filesCached: PageConfig.getOption('cacheFiles').toLowerCase() === 'true',
-    bandwidthSaveMode: false
+    isConnected: true
   };
 
   /**
diff --git a/packages/docmanager-extension/src/index.ts b/packages/docmanager-extension/src/index.ts
index 0ae2a9100955..279d5c2c07be 100644
--- a/packages/docmanager-extension/src/index.ts
+++ b/packages/docmanager-extension/src/index.ts
@@ -143,8 +143,11 @@ const docManagerPlugin: JupyterFrontEndPlugin<IDocumentManager> = {
       translator,
       collaborative: true,
       docProviderFactory: docProviderFactory ?? undefined,
-      bandwidthSaveModeCallback: () => {
-        return info?.bandwidthSaveMode || false;
+      isConnectedCallback: () => {
+        if (info) {
+          return info.isConnected;
+        }
+        return true;
       }
     });
 
diff --git a/packages/docmanager/src/manager.ts b/packages/docmanager/src/manager.ts
index b94cccf2655d..d2089dde586a 100644
--- a/packages/docmanager/src/manager.ts
+++ b/packages/docmanager/src/manager.ts
@@ -37,13 +37,12 @@ export class DocumentManager implements IDocumentManager {
    */
   constructor(options: DocumentManager.IOptions) {
     this.translator = options.translator || nullTranslator;
-    this._bandwidthSaveModeCallback =
-      options.bandwidthSaveModeCallback || (() => false);
     this.registry = options.registry;
     this.services = options.manager;
     this._collaborative = !!options.collaborative;
     this._dialogs = options.sessionDialogs || sessionContextDialogs;
     this._docProviderFactory = options.docProviderFactory;
+    this._isConnectedCallback = options.isConnectedCallback || (() => true);
 
     this._opener = options.opener;
     this._when = options.when || options.manager.ready;
@@ -479,7 +478,7 @@ export class DocumentManager implements IDocumentManager {
     });
     const handler = new SaveHandler({
       context,
-      bandwidthSaveModeCallback: this._bandwidthSaveModeCallback,
+      isConnectedCallback: this._isConnectedCallback,
       saveInterval: this.autosaveInterval
     });
     Private.saveHandlerProperty.set(context, handler);
@@ -605,7 +604,7 @@ export class DocumentManager implements IDocumentManager {
   private _dialogs: ISessionContext.IDialogs;
   private _docProviderFactory: IDocumentProviderFactory | undefined;
   private _collaborative: boolean;
-  private _bandwidthSaveModeCallback: () => boolean;
+  private _isConnectedCallback: () => boolean;
 }
 
 /**
@@ -663,10 +662,10 @@ export namespace DocumentManager {
     collaborative?: boolean;
 
     /**
-     * Autosaving should be paused while this callback function returns `true`.
-     * By default, it always returns `false`.
+     * Autosaving should be paused while this callback function returns `false`.
+     * By default, it always returns `true`.
      */
-    bandwidthSaveModeCallback?: () => boolean;
+    isConnectedCallback?: () => boolean;
   }
 
   /**
diff --git a/packages/docmanager/src/savehandler.ts b/packages/docmanager/src/savehandler.ts
index 9aed0ce30e31..1ea9b71ff55f 100644
--- a/packages/docmanager/src/savehandler.ts
+++ b/packages/docmanager/src/savehandler.ts
@@ -17,8 +17,7 @@ export class SaveHandler implements IDisposable {
    */
   constructor(options: SaveHandler.IOptions) {
     this._context = options.context;
-    this._bandwidthSaveModeCallback =
-      options.bandwidthSaveModeCallback || (() => false);
+    this._isConnectedCallback = options.isConnectedCallback || (() => true);
     const interval = options.saveInterval || 120;
     this._minInterval = interval * 1000;
     this._interval = this._minInterval;
@@ -91,7 +90,7 @@ export class SaveHandler implements IDisposable {
       return;
     }
     this._autosaveTimer = window.setTimeout(() => {
-      if (!this._bandwidthSaveModeCallback()) {
+      if (this._isConnectedCallback()) {
         this._save();
       }
     }, this._interval);
@@ -148,7 +147,7 @@ export class SaveHandler implements IDisposable {
   private _minInterval = -1;
   private _interval = -1;
   private _context: DocumentRegistry.Context;
-  private _bandwidthSaveModeCallback: () => boolean;
+  private _isConnectedCallback: () => boolean;
   private _isActive = false;
   private _inDialog = false;
   private _isDisposed = false;
@@ -169,10 +168,10 @@ export namespace SaveHandler {
     context: DocumentRegistry.Context;
 
     /**
-     * Autosaving should be paused while this callback function returns `true`.
-     * By default, it always returns `false`.
+     * Autosaving should be paused while this callback function returns `false`.
+     * By default, it always returns `true`.
      */
-    bandwidthSaveModeCallback?: () => boolean;
+    isConnectedCallback?: () => boolean;
 
     /**
      * The minimum save interval in seconds (default is two minutes).
diff --git a/packages/filebrowser-extension/src/index.ts b/packages/filebrowser-extension/src/index.ts
index 91f883a2a1dc..cd39f4e90cdc 100644
--- a/packages/filebrowser-extension/src/index.ts
+++ b/packages/filebrowser-extension/src/index.ts
@@ -275,7 +275,10 @@ const factory: JupyterFrontEndPlugin<IFileBrowserFactory> = {
         driveName: options.driveName || '',
         refreshInterval: options.refreshInterval,
         refreshStandby: () => {
-          return info?.bandwidthSaveMode || 'when-hidden';
+          if (info) {
+            return !info.isConnected || 'when-hidden';
+          }
+          return 'when-hidden';
         },
         state:
           options.state === null
diff --git a/packages/hub-extension/src/index.ts b/packages/hub-extension/src/index.ts
index 5099c60edeef..647125a74fa0 100644
--- a/packages/hub-extension/src/index.ts
+++ b/packages/hub-extension/src/index.ts
@@ -155,7 +155,7 @@ const connectionlost: JupyterFrontEndPlugin<IConnectionLost> = {
 
       showingError = true;
       if (info) {
-        info.bandwidthSaveMode = true;
+        info.isConnected = false;
       }
 
       const result = await showDialog({
@@ -171,7 +171,7 @@ const connectionlost: JupyterFrontEndPlugin<IConnectionLost> = {
       });
 
       if (info) {
-        info.bandwidthSaveMode = false;
+        info.isConnected = true;
       }
       showingError = false;