refactoring

Resolve #7779

packages/backend/src/server/api/stream/channels/queue-stats.ts

@@ -0,0 +1,41 @@
+import autobind from 'autobind-decorator';
+import Xev from 'xev';
+import Channel from '../channel';
+
+const ev = new Xev();
+
+export default class extends Channel {
+	public readonly chName = 'queueStats';
+	public static shouldShare = true;
+	public static requireCredential = false;
+
+	@autobind
+	public async init(params: any) {
+		ev.addListener('queueStats', this.onStats);
+	}
+
+	@autobind
+	private onStats(stats: any) {
+		this.send('stats', stats);
+	}
+
+	@autobind
+	public onMessage(type: string, body: any) {
+		switch (type) {
+			case 'requestLog':
+				ev.once(`queueStatsLog:${body.id}`, statsLog => {
+					this.send('statsLog', statsLog);
+				});
+				ev.emit('requestQueueStatsLog', {
+					id: body.id,
+					length: body.length
+				});
+				break;
+		}
+	}
+
+	@autobind
+	public dispose() {
+		ev.removeListener('queueStats', this.onStats);
+	}
+}