Task: Add reflection metadata for decorators and add basic implements for controller and express application and constants and app

package.json

@@ -24,6 +24,7 @@
     "license": "ISC",
     "devDependencies": {
         "@types/express": "^4.17.13",
+        "@types/node": "^16.9.1",
         "@typescript-eslint/eslint-plugin": "^4.30.0",
         "@typescript-eslint/parser": "^4.30.0",
         "dotenv": "^10.0.0",
@@ -36,12 +37,12 @@
         "lint-staged": "^11.1.2",
         "prettier": "2.3.2",
         "ts-node-dev": "^1.1.8",
-        "typescript": "^4.4.2",
-        "@types/node": "^16.9.1"
+        "typescript": "^4.4.2"
     },
     "dependencies": {
+        "@cubetiq/ts-common": "1.0.0",
         "express": "^4.17.1",
-        "@cubetiq/ts-common": "1.0.0"
+        "reflect-metadata": "^0.1.13"
     },
     "lint-staged": {
         "**/*": "prettier --write --ignore-unknown"

src/app.ts

@@ -1,5 +1,8 @@
 // app config
 import "./dotenv"
 
+// reflection metadata for decorator
+import "reflect-metadata"
+
 // core app
 import "./server"

src/app/application.ts

@@ -1,23 +0,0 @@
-import express, { Application as ExpressApp } from "express"
-
-class Application {
-    private readonly _instance: ExpressApp
-
-    get instance(): ExpressApp {
-        return this._instance
-    }
-
-    constructor() {
-        this._instance = express()
-        this._instance.use(express.json())
-        this.registerRoutes()
-    }
-
-    private registerRoutes(): void {
-        this._instance.get("/", (req, res) => {
-            res.send("Hello World!")
-        })
-    }
-}
-
-export default new Application()

src/app/routes.ts

@@ -1,3 +0,0 @@
-const index = (req: any, res: any) => {
-    res.send("Hello World!")
-}

src/application.ts

@@ -0,0 +1,52 @@
+import express, { Application as ExpressApp, Handler } from "express"
+import { controllers } from "./controller"
+import { RouteHandler } from "./decorators/handlers.decorator"
+import { MetadataKeys } from "./constants/metadata.keys"
+
+class Application {
+    private readonly _instance: ExpressApp
+
+    get instance(): ExpressApp {
+        return this._instance
+    }
+
+    constructor() {
+        this._instance = express()
+        this.registerRoutes()
+    }
+
+    private registerRoutes(): void {
+        const info: Array<{ api: string; handler: string }> = []
+
+        controllers.forEach((controller) => {
+            const controllerInstance: { [handlerName: string]: Handler } =
+                new controller() as any
+            const basePath: string = Reflect.getMetadata(
+                MetadataKeys.BASE_PATH,
+                controller
+            )
+            const routers: RouteHandler[] = Reflect.getMetadata(
+                MetadataKeys.ROUTERS,
+                controller
+            )
+            const exRouter = express.Router()
+
+            routers.forEach(({ method, path, handlerName }) => {
+                exRouter[method](
+                    path,
+                    controllerInstance[String(handlerName)]
+                ).bind(controllerInstance)
+                info.push({
+                    api: `${method.toLocaleUpperCase()} ${basePath + path}`,
+                    handler: `${controller.name}.${String(handlerName)}`,
+                })
+            })
+
+            this._instance.use(basePath, exRouter)
+        })
+
+        console.table(info)
+    }
+}
+
+export default new Application()

src/constants/metadata.keys.ts

@@ -0,0 +1,4 @@
+export enum MetadataKeys {
+    BASE_PATH = "base_path",
+    ROUTERS = "routers",
+}

src/controller/index.controller.ts

@@ -0,0 +1,13 @@
+import { Request, Response } from "express"
+import Controller from "../decorators/controller.decorator"
+import { Get } from "../decorators/handlers.decorator"
+
+@Controller("/hello")
+export default class IndexController {
+    constructor() {}
+
+    @Get("")
+    public index(req: Request, res: Response) {
+        res.send(`Hello Index`)
+    }
+}

src/controller/index.ts

@@ -0,0 +1,3 @@
+import IndexController from "./index.controller"
+
+export const controllers = [IndexController]

src/decorators/controller.decorator.ts

@@ -0,0 +1,9 @@
+import { MetadataKeys } from "../constants/metadata.keys"
+
+const Controller = (basePath: string): ClassDecorator => {
+    return (target: any) => {
+        Reflect.defineMetadata(MetadataKeys.BASE_PATH, basePath, target)
+    }
+}
+
+export default Controller

src/decorators/handlers.decorator.ts

@@ -0,0 +1,41 @@
+import { MetadataKeys } from "../constants/metadata.keys"
+
+export enum Method {
+    GET = "get",
+    POST = "post",
+}
+
+export interface RouteHandler {
+    method: Method
+    path: string
+    handlerName: string | symbol
+}
+
+const methodDecoratorFactory = (method: Method) => {
+    return (path: string): MethodDecorator => {
+        return (target: any, propertyKey: string | symbol): void => {
+            const controllerClass = target.constructor
+            const routers: RouteHandler[] = Reflect.hasMetadata(
+                MetadataKeys.ROUTERS,
+                controllerClass
+            )
+                ? Reflect.getMetadata(MetadataKeys.ROUTERS, controllerClass)
+                : []
+
+            routers.push({
+                method,
+                path,
+                handlerName: propertyKey,
+            })
+
+            Reflect.defineMetadata(
+                MetadataKeys.ROUTERS,
+                routers,
+                controllerClass
+            )
+        }
+    }
+}
+
+export const Get = methodDecoratorFactory(Method.GET)
+export const Post = methodDecoratorFactory(Method.POST)

src/server.ts

@@ -1,7 +1,7 @@
 import { createServer } from "http"
 import { SERVER_PORT } from "./app.config"
 import { info } from "@cubetiq/ts-common/dist/log"
-import application from "./app/application"
+import application from "./application"
 
 // get current host id
 const hostId = `${require("os").hostname()}#${process.pid}`
@@ -11,7 +11,7 @@ const app = application.instance
 const httpServer = createServer(app)
 
 info(
-    `Application server running on: ${hostId} at: http://0.0.0.0:${SERVER_PORT} and started at: ${startedAt}`
+    `Application server running on: ${hostId} at port: ${SERVER_PORT} and started at: ${startedAt}`
 )
 httpServer.listen(SERVER_PORT)
 

src/utils/utils.ts

@@ -0,0 +1 @@
+// nothing here for now

tsconfig.json

@@ -9,7 +9,8 @@
         "forceConsistentCasingInFileNames": true,
         "strict": true,
         "lib": ["ES2015"],
-      "skipLibCheck": true
+        "skipLibCheck": true,
+        "experimentalDecorators": true
     },
     "exclude": ["node_modules"]
 }