Open-ILS/src/eg2/src/app/share/util/audio.service.ts

   1 /**
   2  * Plays audio files (alerts, generally) by key name.  Each sound uses a
   3  * dot-path to indicate  the sound.
   4  *
   5  * For example:
   6  *
   7  * this.audio.play('warning.checkout.no_item');
   8  *
   9  * URLs are tested in the following order until an audio file is found
  10  * or no other paths are left to check.
  11  *
  12  * /audio/notifications/warning/checkout/not_found.wav
  13  * /audio/notifications/warning/checkout.wav
  14  * /audio/notifications/warning.wav
  15  *
  16  * Files are only played when sounds are configured to play via
  17  * workstation settings.
  18  */
  19 import {Injectable, EventEmitter} from '@angular/core';
  20 import {ServerStoreService} from '@eg/core/server-store.service';
  21 const AUDIO_BASE_URL = '/audio/notifications/';
  22
  23 @Injectable()
  24 export class AudioService {
  25
  26     // map of requested audio path to resolved path
  27     private urlCache: {[path: string]: string} = {};
  28
  29     constructor(private store: ServerStoreService) {}
  30
  31     play(path: string): void {
  32         if (path) {
  33             this.playUrl(path, path);
  34         }
  35     }
  36
  37     playUrl(path: string, origPath: string): void {
  38         // console.debug(`audio: playUrl(${path}, ${origPath})`);
  39
  40         this.store.getItem('eg.audio.disable').then(audioDisabled => {
  41             if (audioDisabled) { return; }
  42
  43             const url = this.urlCache[path] ||
  44                 AUDIO_BASE_URL + path.replace(/\./g, '/') + '.wav';
  45
  46             const player = new Audio(url);
  47
  48             player.onloadeddata = () => {
  49                 this.urlCache[origPath] = url;
  50                 player.play();
  51                 console.debug(`audio: ${url}`);
  52             };
  53
  54             if (this.urlCache[path]) {
  55                 // when serving from the cache, avoid secondary URL lookups.
  56                 return;
  57             }
  58
  59             player.onerror = () => {
  60                 // Unable to play path at the requested URL.
  61
  62                 if (!path.match(/\./)) {
  63                     // all fall-through options have been exhausted.
  64                     // No path to play.
  65                     console.warn(
  66                         `No suitable URL found for path "${origPath}"`);
  67                     return;
  68                 }
  69
  70                 // Fall through to the next (more generic) option
  71                 path = path.replace(/\.[^\.]+$/, '');
  72                 this.playUrl(path, origPath);
  73             };
  74         });
  75     }
  76 }
  77
  78