Save user language setting to backend (#2784)

* Save user language setting to backend

* Remove hass.selectedLanguage

* Lint

* Address code review comment

* Refactoring translation

* Code review

* Add back selectedLanguage and local app storage

* Move getTranslations to data/frontend.ts

* Fix mock hass

* Rewrite translations-mixin

* revert no need changes

* Final tweak

src/data/frontend.ts

@@ -0,0 +1,38 @@
+import { HomeAssistant } from "../types";
+
+export interface FrontendUserData {
+  language: string;
+}
+
+export const fetchFrontendUserData = async (
+  hass: HomeAssistant,
+  key: string
+): Promise<FrontendUserData> => {
+  const result = await hass.callWS<{ value: FrontendUserData }>({
+    type: "frontend/get_user_data",
+    key,
+  });
+  return result.value;
+};
+
+export const saveFrontendUserData = async (
+  hass: HomeAssistant,
+  key: string,
+  value: FrontendUserData
+): Promise<void> =>
+  hass.callWS<void>({
+    type: "frontend/set_user_data",
+    key,
+    value,
+  });
+
+export const getHassTranslations = async (
+  hass: HomeAssistant,
+  language: string
+): Promise<{}> => {
+  const result = await hass.callWS<{ resources: {} }>({
+    type: "frontend/get_translations",
+    language,
+  });
+  return result.resources;
+};

src/fake_data/provide_hass.ts

@@ -7,7 +7,7 @@ import { demoPanels } from "./demo_panels";
 import { getEntity, Entity } from "./entity";
 import { HomeAssistant } from "../types";
 import { HassEntities } from "home-assistant-js-websocket";
-import { getActiveTranslation } from "../util/hass-translation";
+import { getLocalLanguage } from "../util/hass-translation";
 import { translationMetadata } from "../resources/translations-metadata";
 
 const ensureArray = <T>(val: T | T[]): T[] =>
@@ -87,6 +87,8 @@ export const provideHass = (
     );
   });
 
+  const localLanguage = getLocalLanguage();
+
   const hassObj: MockHomeAssistant = {
     // Home Assistant properties
     auth: {} as any,
@@ -134,7 +136,8 @@ export const provideHass = (
     },
     panelUrl: "lovelace",
 
-    language: getActiveTranslation(),
+    language: localLanguage,
+    selectedLanguage: localLanguage,
     resources: null as any,
     localize: () => "",
 

src/layouts/app/connection-mixin.js

@@ -12,7 +12,7 @@ import LocalizeMixin from "../../mixins/localize-mixin";
 import EventsMixin from "../../mixins/events-mixin";
 
 import { getState } from "../../util/ha-pref-storage";
-import { getActiveTranslation } from "../../util/hass-translation";
+import { getLocalLanguage } from "../../util/hass-translation";
 import { fetchWithAuth } from "../../util/fetch-with-auth";
 import hassCallApi from "../../util/hass-call-api";
 import { subscribePanels } from "../../data/ws-panels";
@@ -49,7 +49,7 @@ export default (superClass) =>
           user: null,
           panelUrl: this._panelUrl,
 
-          language: getActiveTranslation(),
+          language: getLocalLanguage(),
           // If resources are already loaded, don't discard them
           resources: (this.hass && this.hass.resources) || null,
           localize: () => "",

src/layouts/app/sidebar-mixin.ts

@@ -24,7 +24,7 @@ export default (superClass: Constructor<LitElement & HassBaseEl>) =>
       super.firstUpdated(changedProps);
       this.addEventListener("hass-dock-sidebar", (ev) => {
         this._updateHass({ dockedSidebar: ev.detail.dock });
-        storeState(this.hass);
+        storeState(this.hass!);
       });
     }
   };

src/layouts/app/themes-mixin.ts

@@ -1,32 +1,42 @@
 import applyThemesOnElement from "../../common/dom/apply_themes_on_element";
 import { storeState } from "../../util/ha-pref-storage";
 import { subscribeThemes } from "../../data/ws-themes";
+import { Constructor, LitElement } from "lit-element";
+import { HassBaseEl } from "./hass-base-mixin";
+import { HASSDomEvent } from "../../common/dom/fire_event";
 
-export default (superClass) =>
+declare global {
+  // for add event listener
+  interface HTMLElementEventMap {
+    settheme: HASSDomEvent<string>;
+  }
+}
+
+export default (superClass: Constructor<LitElement & HassBaseEl>) =>
   class extends superClass {
-    firstUpdated(changedProps) {
+    protected firstUpdated(changedProps) {
       super.firstUpdated(changedProps);
       this.addEventListener("settheme", (ev) => {
         this._updateHass({ selectedTheme: ev.detail });
         this._applyTheme();
-        storeState(this.hass);
+        storeState(this.hass!);
       });
     }
 
-    hassConnected() {
+    protected hassConnected() {
       super.hassConnected();
 
-      subscribeThemes(this.hass.connection, (themes) => {
+      subscribeThemes(this.hass!.connection, (themes) => {
         this._updateHass({ themes });
         this._applyTheme();
       });
     }
 
-    _applyTheme() {
+    private _applyTheme() {
       applyThemesOnElement(
         document.documentElement,
-        this.hass.themes,
-        this.hass.selectedTheme,
+        this.hass!.themes,
+        this.hass!.selectedTheme,
         true
       );
     }

src/layouts/app/translations-mixin.ts

@@ -1,11 +1,16 @@
 import { translationMetadata } from "../../resources/translations-metadata";
-import { getTranslation } from "../../util/hass-translation";
-import { storeState } from "../../util/ha-pref-storage";
+import {
+  getTranslation,
+  getLocalLanguage,
+  getUserLanguage,
+} from "../../util/hass-translation";
 import { Constructor, LitElement } from "lit-element";
 import { HassBaseEl } from "./hass-base-mixin";
 import { computeLocalize } from "../../common/translations/localize";
 import { computeRTL } from "../../common/util/compute_rtl";
 import { HomeAssistant } from "../../types";
+import { saveFrontendUserData, getHassTranslations } from "../../data/frontend";
+import { storeState } from "../../util/ha-pref-storage";
 
 /*
  * superClass needs to contain `this.hass` and `this._updateHass`.
@@ -16,60 +21,86 @@ export default (superClass: Constructor<LitElement & HassBaseEl>) =>
     protected firstUpdated(changedProps) {
       super.firstUpdated(changedProps);
       this.addEventListener("hass-language-select", (e) =>
-        this._selectLanguage(e)
+        this._selectLanguage((e as CustomEvent).detail.language, true)
       );
-      this._loadResources();
+      this._loadCoreTranslations(getLocalLanguage());
     }
 
     protected hassConnected() {
       super.hassConnected();
-      this._loadBackendTranslations();
-      this.style.direction = computeRTL(this.hass!) ? "rtl" : "ltr";
+      getUserLanguage(this.hass!).then((language) => {
+        if (language && this.hass!.language !== language) {
+          // We just get language from backend, no need to save back
+          this._selectLanguage(language, false);
+        }
+      });
+      this._applyTranslations(this.hass!);
     }
 
     protected hassReconnected() {
       super.hassReconnected();
-      this._loadBackendTranslations();
+      this._applyTranslations(this.hass!);
     }
 
     protected panelUrlChanged(newPanelUrl) {
       super.panelUrlChanged(newPanelUrl);
-      this._loadTranslationFragment(newPanelUrl);
+      // this may be triggered before hassConnected
+      this._loadFragmentTranslations(
+        this.hass ? this.hass.language : getLocalLanguage(),
+        newPanelUrl
+      );
     }
 
-    private async _loadBackendTranslations() {
-      const hass = this.hass;
-      if (!hass || !hass.language) {
+    private _selectLanguage(language: string, saveToBackend: boolean) {
+      if (!this.hass) {
+        // should not happen, do it to avoid use this.hass!
         return;
       }
 
-      const language = hass.selectedLanguage || hass.language;
+      // update selectedLanguage so that it can be saved to local storage
+      this._updateHass({ language, selectedLanguage: language });
+      storeState(this.hass);
+      if (saveToBackend) {
+        saveFrontendUserData(this.hass, "language", { language });
+      }
 
-      const { resources } = await hass.callWS({
-        type: "frontend/get_translations",
-        language,
-      });
+      this._applyTranslations(this.hass);
+    }
 
-      // If we've switched selected languages just ignore this response
-      if ((hass.selectedLanguage || hass.language) !== language) {
+    private _applyTranslations(hass: HomeAssistant) {
+      this.style.direction = computeRTL(hass) ? "rtl" : "ltr";
+      this._loadCoreTranslations(hass.language);
+      this._loadHassTranslations(hass.language);
+      this._loadFragmentTranslations(hass.language, hass.panelUrl);
+    }
+
+    private async _loadHassTranslations(language: string) {
+      const resources = await getHassTranslations(this.hass!, language);
+
+      // Ignore the repsonse if user switched languages before we got response
+      if (this.hass!.language !== language) {
         return;
       }
 
       this._updateResources(language, resources);
     }
 
-    private _loadTranslationFragment(panelUrl) {
+    private async _loadFragmentTranslations(
+      language: string,
+      panelUrl: string
+    ) {
       if (translationMetadata.fragments.includes(panelUrl)) {
-        this._loadResources(panelUrl);
+        const result = await getTranslation(panelUrl, language);
+        this._updateResources(result.language, result.data);
       }
     }
 
-    private async _loadResources(fragment?) {
-      const result = await getTranslation(fragment);
+    private async _loadCoreTranslations(language: string) {
+      const result = await getTranslation(null, language);
       this._updateResources(result.language, result.data);
     }
 
-    private _updateResources(language, data) {
+    private _updateResources(language: string, data: any) {
       // Update the language in hass, and update the resources with the newly
       // loaded resources. This merges the new data on top of the old data for
       // this language, so that the full translation set can be loaded across
@@ -88,14 +119,4 @@ export default (superClass: Constructor<LitElement & HassBaseEl>) =>
       }
       this._updateHass(changes);
     }
-
-    private _selectLanguage(event) {
-      const language: string = event.detail.language;
-      this._updateHass({ language, selectedLanguage: language });
-      this.style.direction = computeRTL(this.hass!) ? "rtl" : "ltr";
-      storeState(this.hass);
-      this._loadResources();
-      this._loadBackendTranslations();
-      this._loadTranslationFragment(this.hass!.panelUrl);
-    }
   };

src/mixins/lit-localize-lite-mixin.ts

@@ -4,7 +4,7 @@ import {
   PropertyDeclarations,
   PropertyValues,
 } from "lit-element";
-import { getActiveTranslation } from "../util/hass-translation";
+import { getLocalLanguage } from "../util/hass-translation";
 import { localizeLiteBaseMixin } from "./localize-lite-base-mixin";
 import { computeLocalize, LocalizeFunc } from "../common/translations/localize";
 
@@ -35,7 +35,8 @@ export const litLocalizeLiteMixin = <T extends LitElement>(
       super();
       // This will prevent undefined errors if called before connected to DOM.
       this.localize = empty;
-      this.language = getActiveTranslation();
+      // Use browser language setup before login.
+      this.language = getLocalLanguage();
     }
 
     public connectedCallback(): void {

src/mixins/localize-lite-base-mixin.ts

@@ -35,7 +35,10 @@ export const localizeLiteBaseMixin = (superClass) =>
     }
 
     private async _updateResources() {
-      const { language, data } = await getTranslation(this.translationFragment);
+      const { language, data } = await getTranslation(
+        this.translationFragment,
+        this.language
+      );
       this.resources = {
         [language]: data,
       };

src/mixins/localize-lite-mixin.ts

@@ -2,7 +2,7 @@
  * Lite mixin to add localization without depending on the Hass object.
  */
 import { dedupingMixin } from "@polymer/polymer/lib/utils/mixin";
-import { getActiveTranslation } from "../util/hass-translation";
+import { getLocalLanguage } from "../util/hass-translation";
 import { localizeLiteBaseMixin } from "./localize-lite-base-mixin";
 import { computeLocalize } from "../common/translations/localize";
 
@@ -16,7 +16,8 @@ export const localizeLiteMixin = dedupingMixin(
         return {
           language: {
             type: String,
-            value: getActiveTranslation(),
+            // Use browser language setup before login.
+            value: getLocalLanguage(),
           },
           resources: Object,
           // The fragment to load.

src/types.ts

@@ -117,8 +117,14 @@ export interface HomeAssistant {
   panelUrl: string;
 
   // i18n
+  // current effective language, in that order:
+  //   - backend saved user selected lanugage
+  //   - language in local appstorage
+  //   - browser language
+  //   - english (en)
   language: string;
-  selectedLanguage?: string;
+  // local stored language, keep that name for backward compability
+  selectedLanguage: string;
   resources: Resources;
   localize: LocalizeFunc;
   translationMetadata: {

src/util/ha-pref-storage.ts

@@ -1,11 +1,12 @@
+import { HomeAssistant } from "../types";
+
 const STORED_STATE = ["dockedSidebar", "selectedTheme", "selectedLanguage"];
 const STORAGE = window.localStorage || {};
 
-export function storeState(hass) {
+export function storeState(hass: HomeAssistant) {
   try {
-    for (var i = 0; i < STORED_STATE.length; i++) {
-      var key = STORED_STATE[i];
-      var value = hass[key];
+    for (const key of STORED_STATE) {
+      const value = hass[key];
       STORAGE[key] = JSON.stringify(value === undefined ? null : value);
     }
   } catch (err) {
@@ -14,10 +15,9 @@ export function storeState(hass) {
 }
 
 export function getState() {
-  var state = {};
+  const state = {};
 
-  for (var i = 0; i < STORED_STATE.length; i++) {
-    var key = STORED_STATE[i];
+  for (const key of STORED_STATE) {
     if (key in STORAGE) {
       state[key] = JSON.parse(STORAGE[key]);
     }
@@ -28,5 +28,7 @@ export function getState() {
 
 export function clearState() {
   // STORAGE is an object if localStorage not available.
-  if (STORAGE.clear) STORAGE.clear();
+  if (STORAGE.clear) {
+    STORAGE.clear();
+  }
 }

src/util/hass-translation.ts

@@ -1,58 +1,89 @@
 import { translationMetadata } from "../resources/translations-metadata";
+import { fetchFrontendUserData } from "../data/frontend";
+import { HomeAssistant } from "../types";
 
-export function getActiveTranslation() {
-  // Perform case-insenstive comparison since browser isn't required to
-  // report languages with specific cases.
-  const lookup = {};
-  /* eslint-disable no-undef */
-  Object.keys(translationMetadata.translations).forEach((tr) => {
-    lookup[tr.toLowerCase()] = tr;
-  });
+const STORAGE = window.localStorage || {};
 
-  // Search for a matching translation from most specific to general
-  function languageGetTranslation(language) {
-    const lang = language.toLowerCase();
+// Chinese locales need map to Simplified or Traditional Chinese
+const LOCALE_LOOKUP = {
+  "zh-cn": "zh-Hans",
+  "zh-sg": "zh-Hans",
+  "zh-my": "zh-Hans",
+  "zh-tw": "zh-Hant",
+  "zh-hk": "zh-Hant",
+  "zh-mo": "zh-Hant",
+  zh: "zh-Hant", // all other Chinese locales map to Traditional Chinese
+};
 
-    if (lookup[lang]) {
-      return lookup[lang];
-    }
-    if (lang.split("-")[0] === "zh") {
-      return lang === "zh-cn" || lang === "zh-sg" ? "zh-Hans" : "zh-Hant";
-    }
-    return null;
+/**
+ * Search for a matching translation from most specific to general
+ */
+function findAvailableLanguage(language: string) {
+  // In most case, the language has the same format with our translation meta data
+  if (language in translationMetadata.translations) {
+    return language;
   }
 
-  let translation = null;
-  let selectedLanguage;
-  if (window.localStorage.selectedLanguage) {
+  // Perform case-insenstive comparison since browser isn't required to
+  // report languages with specific cases.
+  const langLower = language.toLowerCase();
+
+  if (langLower in LOCALE_LOOKUP) {
+    return LOCALE_LOOKUP[langLower];
+  }
+
+  for (const lang in Object.keys(translationMetadata.translations)) {
+    if (lang.toLowerCase() === langLower) {
+      return lang;
+    }
+  }
+}
+
+/**
+ * Get user selected language from backend
+ */
+export async function getUserLanguage(hass: HomeAssistant) {
+  const { language } = await fetchFrontendUserData(hass, "language");
+  if (language) {
+    const availableLanguage = findAvailableLanguage(language);
+    if (availableLanguage) {
+      return availableLanguage;
+    }
+  }
+  return null;
+}
+
+/**
+ * Get browser specific language
+ */
+export function getLocalLanguage() {
+  let language = null;
+  if (STORAGE.selectedLanguage) {
     try {
-      selectedLanguage = JSON.parse(window.localStorage.selectedLanguage);
+      language = findAvailableLanguage(JSON.parse(STORAGE.selectedLanguage));
+      if (language) {
+        return language;
+      }
     } catch (e) {
       // Ignore parsing error.
     }
   }
-  if (selectedLanguage) {
-    translation = languageGetTranslation(selectedLanguage);
-    if (translation) {
-      return translation;
-    }
-  }
   if (navigator.languages) {
     for (const locale of navigator.languages) {
-      translation = languageGetTranslation(locale);
-      if (translation) {
-        return translation;
+      language = findAvailableLanguage(locale);
+      if (language) {
+        return language;
       }
     }
   }
-  translation = languageGetTranslation(navigator.language);
-  if (translation) {
-    return translation;
+  language = findAvailableLanguage(navigator.language);
+  if (language) {
+    return language;
   }
-  if (navigator.language.includes("-")) {
-    translation = languageGetTranslation(navigator.language.split("-")[0]);
-    if (translation) {
-      return translation;
+  if (navigator.language && navigator.language.includes("-")) {
+    language = findAvailableLanguage(navigator.language.split("-")[0]);
+    if (language) {
+      return language;
     }
   }
 
@@ -64,43 +95,50 @@ export function getActiveTranslation() {
 // when DOM is created in Polymer. Even a cache lookup creates noticeable latency.
 const translations = {};
 
-export function getTranslation(fragment?, translationInput?) {
-  const translation = translationInput || getActiveTranslation();
-  const metadata = translationMetadata.translations[translation];
+async function fetchTranslation(fingerprint) {
+  const response = await fetch(`/static/translations/${fingerprint}`, {
+    credentials: "same-origin",
+  });
+  if (!response.ok) {
+    throw new Error(
+      `Fail to fetch translation ${fingerprint}: HTTP response status is ${
+        response.status
+      }`
+    );
+  }
+  return response.json();
+}
+
+export async function getTranslation(
+  fragment: string | null,
+  language: string
+) {
+  const metadata = translationMetadata.translations[language];
   if (!metadata) {
-    if (translationInput !== "en") {
+    if (language !== "en") {
       return getTranslation(fragment, "en");
     }
-    return Promise.reject(new Error("Language en not found in metadata"));
+    throw new Error("Language en is not found in metadata");
   }
-  const translationFingerprint =
-    metadata.fingerprints[
-      fragment ? `${fragment}/${translation}` : translation
-    ];
+  const fingerprint =
+    metadata.fingerprints[fragment ? `${fragment}/${language}` : language];
 
-  // Create a promise to fetch translation from the server
-  if (!translations[translationFingerprint]) {
-    translations[translationFingerprint] = fetch(
-      `/static/translations/${translationFingerprint}`,
-      { credentials: "same-origin" }
-    )
-      .then((response) => response.json())
-      .then((data) => ({
-        language: translation,
-        data,
-      }))
+  // Fetch translation from the server
+  if (!translations[fingerprint]) {
+    translations[fingerprint] = fetchTranslation(fingerprint)
+      .then((data) => ({ language, data }))
       .catch((error) => {
-        delete translations[translationFingerprint];
-        if (translationInput !== "en") {
+        delete translations[fingerprint];
+        if (language !== "en") {
           // Couldn't load selected translation. Try a fall back to en before failing.
           return getTranslation(fragment, "en");
         }
         return Promise.reject(error);
       });
   }
-  return translations[translationFingerprint];
+  return translations[fingerprint];
 }
 
 // Load selected translation into memory immediately so it is ready when Polymer
 // initializes.
-getTranslation();
+getTranslation(null, getLocalLanguage());