Add stop hook to IPFS service

Author: mfcodeworks

lib/ipfs.service.ts

@@ -1,10 +1,10 @@
-import { Injectable, Inject } from '@nestjs/common';
+import { Injectable, Inject, OnApplicationShutdown } from '@nestjs/common';
 import * as IPFS from 'ipfs';
 import { IPFS_MODULE_OPTIONS } from './ipfs.constants';
 import { IPFSModuleOptions } from './interfaces';
 
 @Injectable()
-export class IpfsService {
+export class IpfsService implements OnApplicationShutdown {
     // DEBUG: Give IPFS Node a type when implemented
     private _ipfsNode: any;
 
@@ -15,4 +15,8 @@ export class IpfsService {
             ? this._ipfsNode
             : (this._ipfsNode = await IPFS.create(this._ipfsOptions));
     }
+
+    async onApplicationShutdown(): Promise<void> {
+        await this._ipfsNode && this._ipfsNode.stop();
+    }
 }