catalog-ui/src/app/ng2/shared/translator/translate.service.ts

   1 /*-
   2  * ============LICENSE_START=======================================================
   3  * SDC
   4  * ================================================================================
   5  * Copyright (C) 2017 AT&T Intellectual Property. All rights reserved.
   6  * ================================================================================
   7  * Licensed under the Apache License, Version 2.0 (the "License");
   8  * you may not use this file except in compliance with the License.
   9  * You may obtain a copy of the License at
  10  *
  11  *      http://www.apache.org/licenses/LICENSE-2.0
  12  *
  13  * Unless required by applicable law or agreed to in writing, software
  14  * distributed under the License is distributed on an "AS IS" BASIS,
  15  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  16  * See the License for the specific language governing permissions and
  17  * limitations under the License.
  18  * ============LICENSE_END=========================================================
  19  */
  20
  21 import { Injectable, Inject } from "@angular/core";
  22 import { ITranslateServiceConfig, TranslateServiceConfigToken } from "./translate.service.config";
  23 import { Observer, Subscription, Observable, ConnectableObservable } from 'rxjs/Rx';
  24 import { HttpClient } from "@angular/common/http";
  25
  26 export { ITranslateServiceConfig, TranslateServiceConfigToken };
  27
  28 export interface ITranslateLanguageJson {
  29     [index:string]: string;
  30 }
  31
  32 export interface ITranslateArgs {
  33     [index:string]: any;
  34 }
  35
  36 export class PhraseTranslator {
  37     private _observable:ConnectableObservable<string>;
  38     private _observer:Observer<string>;
  39     private _languageChangeSubscription:Subscription;
  40
  41     private _phraseKey:string;
  42     private _args:ITranslateArgs;
  43     private _language:string;
  44
  45     private _markForCheck:boolean = false;
  46     private _lastParams: {
  47         phraseKey: string;
  48         args: {[index: string]: any};
  49         language: string;
  50     } = {
  51         phraseKey: undefined,
  52         args: undefined,
  53         language: undefined
  54     };
  55
  56     constructor(private translateService:TranslateService) {
  57         this._observable = Observable.create(observer => {
  58             this._observer = observer;
  59             this._languageChangeSubscription = this.translateService.languageChangedObservable.subscribe(language => {
  60                 // using the active language, then force update
  61                 if (!this._language) {
  62                     this.update(true);
  63                 }
  64             });
  65         }).publishReplay(1).refCount();
  66     }
  67
  68     public get observable() {
  69         return this._observable;
  70     }
  71
  72     public destroy() {
  73         this._observer.complete();
  74         this._languageChangeSubscription.unsubscribe();
  75
  76         delete this._observable;
  77         delete this._observer;
  78         delete this._languageChangeSubscription;
  79     }
  80
  81     public shouldUpdate() : boolean {
  82         if (!this._markForCheck) {
  83             return false;
  84         }
  85         this._markForCheck = false;
  86         return (
  87             this._language !== this._lastParams.language ||
  88             this._args !== this._lastParams.args ||
  89             this._phraseKey !== this._lastParams.phraseKey
  90         );
  91     }
  92
  93     public update(forceUpdate:boolean=false) : void {
  94         // only update translation when having subscriptions connected.
  95         if (this._observer && !this._observer.closed) {
  96             if (forceUpdate || this.shouldUpdate()) {
  97                 this._lastParams = {
  98                     phraseKey: this._phraseKey,
  99                     args: this._args,
 100                     language: this._language
 101                 };
 102                 this._markForCheck = false;
 103
 104                 const translated = this.translateService.translate(this._phraseKey, this._args, this._language);
 105                 this._observer.next(translated);
 106             }
 107         }
 108     }
 109
 110     private _changeParam(paramKey:string, value:any, update:boolean) : void {
 111         this[`_${paramKey}`] = value;
 112         this._markForCheck = true;
 113         if (update) {
 114             this.update();
 115         }
 116     }
 117
 118     public changePhraseKey(phraseKey:string, update:boolean=true) : void {
 119         this._changeParam('phraseKey', phraseKey, update);
 120     }
 121
 122     public changeArgs(args:ITranslateArgs, update:boolean=true) :void {
 123         this._changeParam('args', args, update);
 124     }
 125
 126     public changeLangauge(language:string, update:boolean=true) :void {
 127         this._changeParam('language', language, update);
 128     }
 129
 130     public changeParams(phraseKey:string, args:ITranslateArgs={}, language?:string, forceUpdate:boolean=false) {
 131         this._phraseKey = phraseKey;
 132         this._args = args;
 133         this._language = language;
 134         this._markForCheck = true;
 135         this.update(forceUpdate);
 136     }
 137 }
 138
 139
 140 @Injectable()
 141 export class TranslateService {
 142     private _activeLanguage:string;
 143     private _languageChangedObservable:ConnectableObservable<string>;
 144     private _languageChangedObserver:Observer<string>;
 145     private _cacheLanguagesJsons:{[index:string]:ITranslateLanguageJson} = {};
 146     private _cacheLanguagesLoaders:{[index:string]:Observable<ITranslateLanguageJson>} = {};
 147
 148     constructor(@Inject(TranslateServiceConfigToken) private config:ITranslateServiceConfig, private http: HttpClient) {
 149         this.initLanguageObservable();
 150         this.loadAndActivateLanguage(this.config.defaultLanguage);
 151     }
 152
 153     public get languageChangedObservable() : Observable<string> {
 154         return this._languageChangedObservable;
 155     }
 156
 157     public get activeLanguage() {
 158         return this._activeLanguage;
 159     }
 160
 161     private initLanguageObservable() {
 162         this._languageChangedObservable = ConnectableObservable.create(observer => {
 163             this._languageChangedObserver = observer;
 164         }).publishReplay(1);  // replay last emitted change on subscribe
 165         this._languageChangedObservable.connect();
 166     }
 167
 168     private loadLanguageJsonFile(language:string, emitOnLoad:boolean=true) : Observable<ITranslateLanguageJson> {
 169         if (this.config.allowedLanguages.indexOf(language) === -1) {
 170             return Observable.throw(`Language "${language}" is not available.`);
 171         }
 172
 173         if (this._cacheLanguagesJsons[language]) {
 174             return Observable.of(this._cacheLanguagesJsons[language]);
 175         }
 176
 177         if (!(language in this._cacheLanguagesLoaders)) {
 178             const filePath = `${this.config.filePrefix}${language}${this.config.fileSuffix}`;
 179             this._cacheLanguagesLoaders[language] = this.http.get<ITranslateLanguageJson>(filePath)
 180                 .catch(() => Observable.throw(`Failed to load language file for "${language}"`))
 181                 .publish();
 182             (<ConnectableObservable<ITranslateLanguageJson>>this._cacheLanguagesLoaders[language]).connect();
 183             this._cacheLanguagesLoaders[language].subscribe(languageJson => {
 184                     this._cacheLanguagesJsons[language] = languageJson;
 185                     delete this._cacheLanguagesLoaders[language];
 186                     if (emitOnLoad) {
 187                         this._languageChangedObserver.next(language);
 188                     }
 189                     return languageJson;
 190                 });
 191         }
 192         return this._cacheLanguagesLoaders[language];
 193     }
 194
 195     public activateLanguage(language:string) : boolean {
 196         if (this._cacheLanguagesJsons[language]) {
 197             if (language !== this._activeLanguage) {
 198                 this._activeLanguage = language;
 199                 this._languageChangedObserver.next(this._activeLanguage);
 200             }
 201             return true;
 202         }
 203         return false;
 204     }
 205
 206     public loadAndActivateLanguage(language:string) : void {
 207
 208         const loadLanguageObservable = this.loadLanguageJsonFile(language, false);
 209         loadLanguageObservable.subscribe(() => {
 210             this.activateLanguage(language);
 211         }, () => {});
 212     }
 213
 214     public translate(phraseKey:string, args:ITranslateArgs={}, language:string=this._activeLanguage) : string {
 215         const phrase:string = (this._cacheLanguagesJsons[language] || {})[phraseKey] || '';
 216         let translated:string;
 217         if (typeof(phrase) === 'string') {
 218             translated = phrase
 219                 .replace(
 220                     /(^|[^\\]|\\\\)\{\{(\w+)\}\}/g,
 221                     (m, p1, p2) => `${p1}${args[p2]||''}`
 222                 )
 223                 .replace('\\{{', '{{')
 224                 .replace('\\\\', '\\');
 225         }
 226         return translated;
 227     }
 228
 229     public createPhraseTranslator(phraseKey?:string, args?:ITranslateArgs, language?:string) : PhraseTranslator {
 230         const phraseTranslator = new PhraseTranslator(this);
 231         phraseTranslator.changeParams(phraseKey, args, language);
 232         return phraseTranslator;
 233     }
 234 }