From 18c3ef991a85043facd2a606efa838d5398ff40b Mon Sep 17 00:00:00 2001
From: allburov <allburov@gmail.com>
Date: Fri, 19 Aug 2022 10:15:32 +0300
Subject: [PATCH] Handle errors and show fullstack for 500

---
 src/api/exception.filter.ts | 30 ++++++++++++++++++++++++++++++
 src/main.ts                 |  2 ++
 src/whatsapp.service.ts     | 24 ++++++++++++++++++------
 3 files changed, 50 insertions(+), 6 deletions(-)
 create mode 100644 src/api/exception.filter.ts

diff --git a/src/api/exception.filter.ts b/src/api/exception.filter.ts
new file mode 100644
index 00000000..6b7b05ff
--- /dev/null
+++ b/src/api/exception.filter.ts
@@ -0,0 +1,30 @@
+import {ArgumentsHost, Catch, ExceptionFilter, HttpException, HttpStatus,} from '@nestjs/common';
+import {Request, Response} from 'express';
+
+@Catch()
+export class AllExceptionsFilter implements ExceptionFilter {
+    catch(exception: HttpException | Error, host: ArgumentsHost): void {
+        const ctx = host.switchToHttp();
+        const response = ctx.getResponse<Response>();
+        const request = ctx.getRequest<Request>();
+
+        if (exception instanceof HttpException) {
+            response
+                .status(exception.getStatus())
+                .json(exception.getResponse());
+            return
+        }
+
+        const httpStatus = HttpStatus.INTERNAL_SERVER_ERROR
+        response
+            .status(httpStatus)
+            .json({
+                statusCode: httpStatus,
+                timestamp: new Date().toISOString(),
+                path: request.url,
+                error: exception.message,
+                stack: exception.stack,
+            });
+
+    }
+}
diff --git a/src/main.ts b/src/main.ts
index e561b391..830f3bff 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -2,6 +2,7 @@ import {NestFactory} from '@nestjs/core';
 import {AppModule} from './app.module';
 import {DocumentBuilder, SwaggerModule} from "@nestjs/swagger";
 import {WhatsappConfigService} from "./config.service";
+import {AllExceptionsFilter} from "./api/exception.filter";
 
 async function bootstrap() {
     const app = await NestFactory.create(AppModule, {
@@ -10,6 +11,7 @@ async function bootstrap() {
     });
 
     app.enableShutdownHooks();
+    app.useGlobalFilters(new AllExceptionsFilter());
     const options = new DocumentBuilder()
         .setTitle('WhatsApp HTTP API')
         .setDescription('WhatsApp HTTP API that you can configure in a click!')
diff --git a/src/whatsapp.service.ts b/src/whatsapp.service.ts
index 4a253a67..2e0b3dcb 100644
--- a/src/whatsapp.service.ts
+++ b/src/whatsapp.service.ts
@@ -1,8 +1,9 @@
 import {create, Message, Whatsapp} from "venom-bot";
-import {ConsoleLogger, Injectable, OnApplicationShutdown} from "@nestjs/common";
+import {ConsoleLogger, Injectable, NotFoundException, OnApplicationShutdown} from "@nestjs/common";
 import * as path from "path";
 import {WhatsappConfigService} from "./config.service";
 import {WHATSAPP_DEFAULT_SESSION_NAME} from "./api/all.dto";
+import {UnprocessableEntityException} from "@nestjs/common/exceptions/unprocessable-entity.exception";
 import request = require('requestretry');
 import mime = require('mime-types');
 import fs = require('fs');
@@ -86,13 +87,13 @@ export class WhatsappService {
 
     public async getScreenshotOrQRCode(): Promise<Buffer | string> {
         if (this.status === WhatsappStatus.STARTING) {
-            //    TODO: raise an error please wait
+            throw new UnprocessableEntityException(`The session is starting, please try again after few seconds`);
         } else if (this.status === WhatsappStatus.SCAN_QR_CODE) {
             return this.getQRCode()
         } else if (this.status === WhatsappStatus.WORKING) {
             return await this.whatsapp.page.screenshot()
         } else {
-            //    TODO: throw unknown status
+            throw new UnprocessableEntityException(`Unknown status - ${this.status}`);
         }
 
     }
@@ -159,6 +160,11 @@ export class WhatsappService {
     }
 
     public getWhatsapp() {
+        if (this.status != WhatsappStatus.WORKING) {
+            throw new UnprocessableEntityException(
+                `The session status is "${this.status}". Please scan QR code first by using GET /screenshot method.`,
+            );
+        }
         return this.whatsapp
 
     }
@@ -215,12 +221,18 @@ export class WhatsappSessionManager implements OnApplicationShutdown {
     }
 
     getService(name: string): WhatsappService {
-        return this.sessions[name]
+        const session = this.sessions[name]
+        if (!session) {
+            throw new NotFoundException(
+                `We didn't find a session with name "${name}". Please start it first by using POST /sessions/start request`,
+            );
+        }
+        return session
     }
 
     getSession(name: string): Whatsapp {
-        // TODO: Check session exists
-        return this.sessions[name].getWhatsapp()
+        const service = this.getService(name)
+        return service.getWhatsapp()
     }
 
     stopSession(name: string) {