BETTERZON-38: Added error handler, preparation for DB accessing

Backend/Backend.iml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="WEB_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+      <excludeFolder url="file://$MODULE_DIR$/dist" />
+    </content>
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>

Backend/package.json

@@ -14,7 +14,9 @@
     "cors": "^2.8.5",
     "dotenv": "^8.2.0",
     "express": "^4.17.1",
-    "helmet": "^4.2.0"
+    "helmet": "^4.2.0",
+    "mariadb": "^2.5.1",
+    "typeorm": "^0.2.29"
   },
   "devDependencies": {
     "@types/cors": "^2.8.8",

Backend/src/common/http-exception.ts

@@ -0,0 +1,13 @@
+export default class HttpException extends Error {
+    statusCode: number;
+    message: string;
+    error: string | null;
+
+    constructor(statusCode: number, message: string, error?: string) {
+        super(message);
+
+        this.statusCode = statusCode;
+        this.message = message;
+        this.error = error || null;
+    }
+}

Backend/src/index.ts

@@ -7,6 +7,8 @@ import express from "express";
 import cors from "cors";
 import helmet from "helmet";
 import { productsRouter } from "./products/products.router";
+import { errorHandler } from "./middleware/error.middleware";
+import {notFoundHandler} from "./middleware/notFound.middleware";
 
 dotenv.config();
 
@@ -33,6 +35,9 @@ app.use(cors());
 app.use(express.json());
 app.use("/products", productsRouter);
 
+app.use(errorHandler);
+app.use(notFoundHandler);
+
 
 /**
  * Server Activation

Backend/src/middleware/error.middleware.ts

@@ -0,0 +1,15 @@
+import HttpException from "../common/http-exception";
+import { Request, Response, NextFunction } from "express";
+
+export const errorHandler = (
+    error: HttpException,
+    request: Request,
+    response: Response,
+    next: NextFunction
+) => {
+    const status = error.statusCode || 500;
+    const message =
+        error.message || "It's not you. It's us. We are having some problems.";
+
+    response.status(status).send(message);
+};

Backend/src/middleware/notFound.middleware.ts

@@ -0,0 +1,12 @@
+import { Request, Response, NextFunction } from "express";
+
+export const notFoundHandler = (
+    request: Request,
+    response: Response,
+    next: NextFunction
+) => {
+
+    const message = "Resource not found";
+
+    response.status(404).send(message);
+};