Update maxEvenListeneres and try to fix the memory leak

src/app.ts

 import express = require('express');
 import bodyParser = require('body-parser');
-import cors = require('cors')
+import cors = require('cors');
 import {ApiController, InterfaceRequestApi} from './controller/api'
 import {Validator} from './middleware/validator';
 import {HealthcheckController} from './controller/healthcheck';
 import {Core} from 'geolinker-common';
 import {NextFunction, Response} from "express";
-import {kafkaEventEmitter} from './utils/kafka-event-container';
+import kafkaEventEmitter from './utils/kafka-event-container';
 import fmt = require('bunyan-format');
 import KafkaAvro = require('kafka-avro');
 import timer from './utils/timer';

src/controller/api.ts

 import {NextFunction, Request, Response} from 'express';
-import {kafkaEventEmitter} from '../utils/kafka-event-container';
+import kafkaEventEmitter from '../utils/kafka-event-container';
 import {core} from '../app';
 import timer from "../utils/timer";
 import { ResponseCollector} from '../utils/response-collector';
@@ -52,6 +52,8 @@ export interface InterfaceStreamAppResponse {
 }
 
 export class ApiController {
+
+    static unsubscribeTimeout = 2000;
     /**
      * If a node contains an url with special characters like ? or # it needs to be urlencoded. We check if we find more than one of those characters to be sure the encoding will work properly
      * @param req

src/middleware/cache.ts

@@ -4,12 +4,19 @@ const NodeCache = require( "node-cache" );
 const shajs = require('sha.js');
 import {InterfaceFinalAnswer} from '../utils/response-collector';
 
+// prepare cache storage. We will cash answers for 5 minutes
 const cacheStore: InterfaceCacheStore = new NodeCache( { stdTTL: 3600, checkperiod: 120 } );
 
+/**
+ * Extend response interface and add sendResponse property
+ */
 export interface InterfaceCachedResponse extends Response{
     sendResponse: (body: any) => Response;
 }
 
+/**
+ * CacheStore interface
+ */
 export interface InterfaceCacheStore {
     set(key: string | number, value: any, ttl?: number): void;
     get(key: string | number): any;
@@ -17,10 +24,16 @@ export interface InterfaceCacheStore {
 }
 
 /**
- * Small wrapper to cache an get kafka answers
+ * Small wrapper to cache and get kafka answers
  */
 export class KafkaCache {
 
+    /**
+     * Check if we have an answer of kafka in the cash and if possible send it
+     * @param req
+     * @param res
+     * @param next
+     */
     static middleware(req: Request, res: InterfaceCachedResponse, next: NextFunction) {
         const url = req.url || req.originalUrl;
         const id = shajs('sha256').update(url).digest('hex');

src/utils/kafka-event-container.ts

 const EventEmitter = require('events');
 class KafkaEventEmitter extends EventEmitter {}
-export const kafkaEventEmitter = new KafkaEventEmitter();
+// event emitter for kafka events
+const kafkaEventEmitter = new KafkaEventEmitter();
+// allow more than 10 parallel event listeners
+kafkaEventEmitter.setMaxListeners(100);
+export default kafkaEventEmitter;