ember-cli-horizon/addon/services/horizon-connection.js

An Ember service for managing a Horizon connection, and an adapter to request data from that connection.

import Ember from 'ember';
import horizon from 'npm:@horizon/client/dist/horizon';

import config from 'ember-get-config';

/**
 * @class HorizonConnectionService
 *
 * This service gives an easy to work with way of connecting to Horizon.
 */
export default Ember.Service.extend({
    _connSuccSub: null,
    _connErrSub: null,
    _readyPromise: null,

    // NOTE: This is not updated with Ember.set(), thus not observable.
    // It should only be used for sync checks, for async operations use
    // this.connect() which reurns a connection promise.
    isReady: false,
    // This is the actual horizon object, it can be used directly or accessed
    // as the value passed to callbacks of the this.connect() promise.
    hz: horizon(config.horizon || {}),

    /**
     * @method connect
     * @return {Promise} promise
     *
     * If no connection has been attempted yet, attempt it and return a promise,
     * else return the precious connection promise.
     */
    connect() {
        if (!this._readyPromise) {
            this._readyPromise = new Ember.RSVP.Promise((resolve, reject) => {
                this._connSuccSub = this.hz.onReady(() => {
                    console.log('Horizon connected');
                    this._cleanupConnSubs();
                    this.isReady = true;
                    resolve(this.hz);
                });
                this._connErrSub = this.hz.onSocketError(() => {
                    console.error('Horizon connection failed');
                    this._cleanupConnSubs();
                    reject(this.hz);
                });
                this.hz.connect();
            });
        }

        return this._readyPromise;
    },

    /**
     * @method _cleanupConnSubs
     * @private
     *
     * Cleanup RxJS subscriptions after connection succeeds or fails.
     */
    _cleanupConnSubs() {
        if (this._connSuccSub) {
            this._connSuccSub.unsubscribe();
            this._connSuccSub = null;
        }

        if (this._connErrSub) {
            this._connErrSub.unsubscribe();
            this._connErrSub = null;
        }
    }
});