fix / improve types

superset-frontend/src/setup/setupApp.ts

@@ -24,6 +24,7 @@ import {
   ClientErrorObject,
 } from '@superset-ui/core';
 import setupErrorMessages from 'src/setup/setupErrorMessages';
+import parseCookie from 'src/utils/parseCookie';
 
 // eslint-disable-next-line @typescript-eslint/no-unused-vars
 declare global {
@@ -59,6 +60,22 @@ function toggleCheckbox(apiUrlPrefix: string, selector: string) {
     );
 }
 
+function syncBrowserThemePreferenceWithCookie() {
+  try {
+    const currentPreference = window.matchMedia('(prefers-color-scheme: dark)')
+      .matches
+      ? 'dark'
+      : 'light';
+    const cookies = parseCookie();
+
+    if (cookies.superset_theme !== currentPreference) {
+      document.cookie = `superset_theme=${currentPreference}; path=/; SameSite=Lax; secure`;
+    }
+  } catch (err) {
+    console.warn('Failed to sync theme preference', err);
+  }
+}
+
 export default function setupApp() {
   $(document).ready(function () {
     $(':checkbox[data-checkbox-api-prefix]').change(function (
@@ -94,6 +111,9 @@ export default function setupApp() {
   window.$ = $;
   window.jQuery = $;
 
+  // set up the OS-level preference around light/dark mode
+  syncBrowserThemePreferenceWithCookie();
+
   // set up app wide custom error messages
   setupErrorMessages();
 }

superset-frontend/src/theme/ThemeController.tsx

@@ -25,6 +25,7 @@ import {
   themeObject,
 } from '@superset-ui/core';
 import { ThemeMode } from '@superset-ui/core/theme/types';
+import getBootstrapData from 'src/utils/getBootstrapData';
 
 export class LocalStorageAdapter implements ThemeStorage {
   getItem(key: string): string | null {
@@ -70,7 +71,13 @@ export class ThemeController {
     this.storageKey = options.storageKey || 'superset-theme';
     this.modeStorageKey = options.modeStorageKey || `${this.storageKey}-mode`;
     this.defaultTheme = options.defaultTheme || {};
-    this.themeObject = options.themeObject;
+
+    // Load themeObject — either passed in or auto-loaded from bootstrap
+    if (options.themeObject) {
+      this.themeObject = options.themeObject;
+    } else {
+      this.themeObject = ThemeController.getThemeFromBootstrapData();
+    }
 
     // Load customizations from storage
     const savedThemeJson = this.storage.getItem(this.storageKey);
@@ -103,8 +110,32 @@ export class ThemeController {
   }
 
   /**
-   * Cleans up listeners. Should be called when the controller is no longer needed.
+   * Load theme object directly from bootstrapData if not provided explicitly
+   * Note that there is special logic/handling to support getting the first request
+   * where the backend doesn't know about user preferences yet.
+   * In that case, since the backend doesn't know about the user preferences,
+   * it will return both themes to the back as part of the bootstrap data, leaving
+   * the decision to the frontend to pick the right one under `bootstrapData.themes`
+   * once the backend knows about the user preferences, it will return only `bootstrapData.theme`
+   * which takes precedence over `bootstrapData.themes` (not available in this case)
    */
+  private static getThemeFromBootstrapData(): Theme {
+    const bootstrapData = getBootstrapData().common;
+
+    let themeConfig: AnyThemeConfig = {};
+
+    if (bootstrapData.theme) {
+      themeConfig = bootstrapData.theme;
+    } else if (bootstrapData.themes) {
+      const systemMode = ThemeController.getSystemMode();
+      const preferred = systemMode;
+      if (bootstrapData.themes[preferred]) {
+        themeConfig = bootstrapData.themes[preferred];
+      }
+    }
+    return Theme.fromConfig(themeConfig);
+  }
+
   public destroy(): void {
     this.mediaQuery.removeEventListener('change', this.handleSystemThemeChange);
   }
@@ -138,7 +169,6 @@ export class ThemeController {
     if (!newCustomizations.algorithm) {
       this.currentMode = ThemeMode.LIGHT;
     }
-
     if (newCustomizations?.algorithm) {
       this.currentMode = newCustomizations.algorithm as ThemeMode;
     }
@@ -184,7 +214,6 @@ export class ThemeController {
     if (this.systemMode === newSystemMode) return;
 
     this.systemMode = newSystemMode;
-    // If the current mode is SYSTEM, we need to re-apply the theme
     if (this.currentMode === ThemeMode.SYSTEM) {
       this.applyTheme();
       this.notifyListeners();
@@ -221,7 +250,6 @@ export class ThemeController {
 
   private persist(): void {
     this.storage.setItem(this.modeStorageKey, this.currentMode);
-
     const { algorithm, ...persistedCustomizations } = this.customizations;
     this.storage.setItem(
       this.storageKey,

superset-frontend/src/types/bootstrapTypes.ts

@@ -11,6 +11,7 @@ import { TimeLocaleDefinition } from 'd3-time-format';
 import { isPlainObject } from 'lodash';
 import { Languages } from 'src/features/home/LanguagePicker';
 import type { FlashMessage } from 'src/components';
+import type { SerializableThemeConfig } from '@superset-ui/core/theme/types';
 
 /**
  * Licensed to the Apache Software Foundation (ASF) under one
@@ -153,7 +154,12 @@ export interface CommonBootstrapData {
   language_pack: LanguagePack;
   extra_categorical_color_schemes: ColorSchemeConfig[];
   extra_sequential_color_schemes: SequentialSchemeConfig[];
-  theme: JsonObject;
+  // Depending on if the cookie is set, either theme or themes will be defined.
+  theme?: SerializableThemeConfig;
+  themes?: {
+    light: SerializableThemeConfig;
+    dark: SerializableThemeConfig;
+  };
   menu_data: MenuData;
   d3_format: Partial<FormatLocaleDefinition>;
   d3_time_format: Partial<TimeLocaleDefinition>;

superset-frontend/src/views/RootContextProviders.tsx

@@ -18,7 +18,7 @@
  */
 
 import { Route } from 'react-router-dom';
-import { getExtensionsRegistry, themeObject } from '@superset-ui/core';
+import { getExtensionsRegistry } from '@superset-ui/core';
 import { Provider as ReduxProvider } from 'react-redux';
 import { QueryParamProvider } from 'use-query-params';
 import { DndProvider } from 'react-dnd';
@@ -33,10 +33,7 @@ import '../preamble';
 
 const { common } = getBootstrapData();
 
-if (Object.keys(common?.theme || {}).length > 0) {
-  themeObject.setConfig(common.theme);
-}
-const themeController = new ThemeController({ themeObject });
+const themeController = new ThemeController();
 
 const extensionsRegistry = getExtensionsRegistry();
 export const RootContextProviders: React.FC = ({ children }) => {

superset/config.py

@@ -563,12 +563,12 @@ DEFAULT_FEATURE_FLAGS: dict[str, bool] = {
     # Adds a switch to the navbar to easily switch between light and dark themes.
     # This is intended to use for development, visual review, and theming-debugging
     # purposes.
-    "THEME_ENABLE_DARK_THEME_SWITCH": False,
+    "THEME_ENABLE_DARK_THEME_SWITCH": True,
     # Adds a theme editor as a modal dialog in the navbar. Allows people to type in JSON
     # and see the changes applied to the current theme.
     # This is intended to use for theme creation, visual review and theming-debugging
     # purposes.
-    "THEME_ALLOW_THEME_EDITOR_BETA": False,
+    "THEME_ALLOW_THEME_EDITOR_BETA": True,
     # Allow users to optionally specify date formats in email subjects, which will
     # be parsed if enabled
     "DATE_FORMAT_IN_EMAIL_SUBJECT": False,
@@ -669,17 +669,17 @@ COMMON_BOOTSTRAP_OVERRIDES_FUNC: Callable[  # noqa: E731
 # This is merely a default
 EXTRA_CATEGORICAL_COLOR_SCHEMES: list[dict[str, Any]] = []
 
-# THEME is used for setting a custom theme to Superset, it follows the ant design
-# theme structure
+# THEME and THEME_DARK are used for setting a custom theme to Superset,
+# it follows the ant design theme structure.
 # You can use the AntDesign theme editor to generate a theme structure
 # https://ant.design/theme-editor
-# To expose a JSON theme editor modal that can be triggered from the navbar
-# set the `ENABLE_THEME_EDITOR` feature flag to True.
-#
-# To set up the dark theme:
-# THEME = {"algorithm": "dark"}
+# The config are set as a callable returning an antd-compatible theme object
+# so that themes can be hot-swapped by fetching a theme object definition remotely
 
-THEME: dict[str, Any] = {}
+# Whether to respect the user's OS dark mode setting. If True, THEME_DARK must be set
+THEME_RESPECT_USER_OS_DARK_SETTING = False
+THEME: dict[str, Any] = lambda: {}  # NOQA
+THEME_DARK: dict[str, Any] = lambda: {"algorithm": "dark"}  # NOQA
 
 # EXTRA_SEQUENTIAL_COLOR_SCHEMES is used for adding custom sequential color schemes
 # EXTRA_SEQUENTIAL_COLOR_SCHEMES =  [

superset/views/base.py

@@ -30,6 +30,7 @@ from flask import (
     g,
     get_flashed_messages,
     redirect,
+    request,
     Response,
     session,
     url_for,
@@ -292,6 +293,27 @@ def menu_data(user: User) -> dict[str, Any]:
     }
 
 
+def get_theme_bootstrap_data() -> dict[str, Any]:
+    """
+    On frst call, the cookie related to light/dark may not be set,
+    so we send both the dark and light themes
+    in the "themes" key. Once the cookie is set, we simply use the `theme` key.
+    Logic on the frontend looks for `theme`, and if it's not available, falls back
+    to `themes` and picks the right one
+    """
+    theme_cookie = request.cookies.get("superset_theme")
+    if conf["THEME_RESPECT_USER_OS_DARK_SETTING"] or theme_cookie == "light":
+        return {"theme": conf["THEME"]()}
+    elif theme_cookie == "dark":
+        return {"theme": conf["THEME_DARK"]()}
+    return {
+        "themes": {
+            "light": conf["THEME"](),
+            "dark": conf["THEME_DARK"](),
+        }
+    }
+
+
 @cache_manager.cache.memoize(timeout=60)
 def cached_common_bootstrap_data(  # pylint: disable=unused-argument
     user_id: int | None, locale: Locale | None
@@ -371,10 +393,10 @@ def cached_common_bootstrap_data(  # pylint: disable=unused-argument
         "feature_flags": get_feature_flags(),
         "extra_sequential_color_schemes": conf["EXTRA_SEQUENTIAL_COLOR_SCHEMES"],
         "extra_categorical_color_schemes": conf["EXTRA_CATEGORICAL_COLOR_SCHEMES"],
-        "theme": conf["THEME"],
         "menu_data": menu_data(g.user),
     }
     bootstrap_data.update(conf["COMMON_BOOTSTRAP_OVERRIDES_FUNC"](bootstrap_data))
+    bootstrap_data.update(get_theme_bootstrap_data())
     return bootstrap_data