PENP-T

PostgreSQL + Express + Node + Prisma + TypeScript API Template

Getting Started

Understanding the folder structure

├── prisma
│   └── schema.prisma
├── server.ts
├── src
│   ├── controllers
│   │   ├── health
│   │   └── index.ts
│   ├── globals
│   │   ├── constants
│   │   ├── errors
│   │   └── success
│   ├── interfaces
│   ├── middlewares
│   ├── routers
│   └── utils

1. The Database schema is in schema/prisma.schema
2. server.ts is the starting point for the application
3. API Controllers should be made inside src/controllers. Use subdirectories or files as per need.
4. API Middlewares exist in src/middlewares.
5. Once the Controllers and Middlewares are made, those are exposed at endpoints in src/routers.
6. Every Controller and Middleware function is of type Interfaces.Controllers.Async or Interfaces.Middlewares.Async (A Sync variant exists too). All these interfaces are written in src/interfaces.
7. Any utility functions (for the purpose of abstracting/reusing code in Controllers/Middlewares) should be made in src/utils.
8. src/global directory contains constants and helper functions for handling responses and error.

Demo

Let's create a DEMO GET endpoint at /test which returns a message "Hello from test"

1. Create a folder in src/controllers named test. Inside this folder, create a file called get.ts.

// src/controllers/test/get.ts

import * as Interfaces from "../../interfaces"
import * as Utils from "../../utils"

const get: Interfaces.Controllers.Sync = (req, res, next) => {
  /*
    We could use `return res.json("Hello from test")` too
    but the response json would be of the structure:
    "Hello from test".
    To maintain uniformity across all response objects,
    we will use Utils.Response.success() and Utils.Response.error() helper functions.
    We pass into these function the actual data we need to send to the client
    and these function would create a json structure of:
    {
      "status" : 200
      "msg" : "Actual Data"
    }
    Similarly, Utils.Response.error would create a similar object but with status code 400.
    **It is always recommended to send the response to the client through these helper functions only.**
  */
  return res.json(Utils.Response.success("Hello from test"))
}

export { get };

2. Next, create an index.ts inside src/controllers/test and import-export all the controllers. In this case simply import the get controller and export it.

// src/controllers/test/index.ts
import { get } from "./get"
export { get }

3. Now edit the src/controllers/index.ts file to import all controllers inside src/controllers/test

// src/controllers/test/index.ts
import * as Health from "./health";
import * as Test from "./test"
export { Health, Test };

4. Now, lets expose our newly made controller at the endpoint /test. In the src/routers directory, create a new file named test.ts.

// src/routers/test.ts
import express from "express";
import * as Controllers from "../controllers";

const router = express.Router();

router.get("/", Controllers.Test.get);

export default router;

5. Notice the mount-point for the controller is / and not /test. This is because, we haven't mounted this router onto our server yet. When we mount it on the server, we will mount this router on /test. So, doing a GET request on /test/ will hit our Controller function. Import export the router object similarly.

6. Mounting the router is simple. Simple edit server.ts and add the following line:

// server.ts
...
app
  .use(cors())
  .use(helmet())
  .use(morgan("dev"))
  .use(express.json())
  .use(express.urlencoded({ extended: true }));

// Routers
app.use(`${Constants.System.ROOT}/`, Routers.Health);
app.use(`${Constants.System.ROOT}/test`, Routers.Test);

// Error Handlers
app.use(Middlewares.Error.errorHandler);
...