Access multiple Realtime Databases of the same fir

Question

I found some explanations about connecting multiple databases from separate app projects with angularfire2. But I would like to access databases within the same project.

The documentation stated:

// Get the default database instance for an app
var database = firebase.database();

// Get a secondary database instance by URL
var database = firebase.database('https://testapp-1234.firebaseio.com');

How can I do this with angularfire2?

Answer 1

I know you got a working answer here : https://github.com/angular/angularfire2/issues/1567

tested with : "angularfire2": "^5.0.0-rc.6.0", "firebase": "^4.12.1"

I've built a minimalist wrapper inspired of the #1567 I'd like to share. There are 2 methods with different or same project to use multiple databases.

You'll probably use the first one, I don't really understand the point of using multiple databases within multiple project.

@Injectable()
export class AngularFireWrapper {

  // Default database 
  private _firebaseDb = this.afDb.database;

  constructor(private afDb: AngularFireDatabase,
              @Optional() dbName: string) {

    console.log('Hello AngularFireWrapper, db :', dbName || 'default');

    // 1st Method, same project, same auth
    // environment.dbUrls = {
    //   ...
    //   otherDb: 'https://DB_NAME_SAME_PROJECT.firebaseio.com/'
    // }

    if (dbName && environment.dbUrls[dbName]) {
      const app: any = this.afDb.app;
      this._firebaseDb = app.database(environment.dbUrls[dbName]);
    }

    // 2nd Method, other project, different auth =/
    // environment.dbConfigs = {
    //   ...
    //   otherDb: {...} // usual firebase configs 
    // }

    if (dbName && environment.dbConfigs[dbName]) {
      this._firebaseDb = firebase.initializeApp(environment.dbConfigs[dbName], dbName)
        .database();
    }
  }

  db(dbName): AngularFireWrapper {
    return new AngularFireWrapper(this.afDb, dbName);
  }

  object(path: string): AngularFireObject<any> {
    const ref = this._firebaseDb.ref(path);
    return this.afDb.object(ref);
  }

  list(path: string, queryFn?: QueryFn): AngularFireList<any> {
    const ref = this._firebaseDb.ref(path);
    return this.afDb.list(ref, queryFn);
  }
}

Copy-Paste, inject it as you usually do with your custom services and then :

export class MyApp {
  constructor(private afW: AngularFireWrapper) {

    this.afW.object('test')
      .valueChanges()
      .subscribe(console.log)
    // => output default db values

    this.afW.db('otherDb').object('test')
      .valueChanges()
      .subscribe(console.log)
    // => output otherDb values
  }