jwt-demo-user-registration.md

JWT Demo: User Signup API

With the User model in place, we can start to implement the REST APIs for user signup and login. Let's start with the API for user sign up.

Integration test for user sign up

We will write a test case first for the API. Since we are going to test the API working with a real database, we usually call such test cases as "integration tests".

Firstly, create a directory integration_test in the project root directory.

Inside this directory, create a file user_signup.test.js with the following content:

process.env.NODE_ENV = "integration";

const testDB = require("../test_helper/in_memory_mongodb_setup");
const request = require("supertest");
const app = require("../src/app");
const status = require("http-status");

beforeAll(testDB.setup);
afterAll(testDB.teardown);

describe("New user signup", () => {
  test("Register a new user successfully", async () => {
    const username = "luke";
    const email = "[email protected]";
    const password = "mypassword";

    let response = await request(app)
      .post("/api/user/signup")
      .send({ user: { username, email, password } });
    let userJson = response.body.user;

    expect(response.statusCode).toBe(status.OK);
    expect(userJson).toBeDefined();
    expect(userJson.username).toEqual(username);
    expect(userJson.email).toEqual(email);
  });
});

When you run this test case, you would notice that it fail with the following error:

  Expected: 200
  Received: 404

      20 |     let userJson = response.body.user;
      21 |
    > 22 |     expect(response.statusCode).toBe(200);

You got HTTP 404 in the response. That's because we haven't added the route handler for this /api/user/signup yet.

Let's add an Express router for all user related call.

In app.js, add the following lines in the "routers" section.

const userRouter = require("./routes/user_api");
app.use("/api/user", userRouter);

In routes folder, create a new file called user_api.js with the following content:

const express = require("express");
const router = express.Router();
const handleAsyncError = require("express-async-wrap");
const userHandler = require("../handler/user_handler");

router.post("/signup", handleAsyncError(userHandler.registerNewUser));

module.exports = router;

All the route handlers can be put in the handler folder, let's create that directory, and then create a new file user_handler.js in that directory.

The content of user_handler.js is:

const User = require("../model/user");

async function registerNewUser(req, res) {
  var user = new User();

  user.username = req.body.user.username;
  user.email = req.body.user.email;
  user.setPassword(req.body.user.password);

  await user.save();
  return res.json({ user: { username: user.username, email: user.email } });
}

module.exports = {
  registerNewUser
};

This may look a bit different than the route handlers you usually write, that's because I decided to extract the route handlers into a separate file. Putting route handlers into a separate file make it easier to write unit tests for them, because the test cases for the handlers has no dependency on Express framework at all.

Exercise

Write more test cases for the user sign up API

• If another user tries to sign up with user name tom, the HTTP response code should be 422 (Unprocessable Entity) instead of 200 (OK). The JSON body in the HTTP response can also contain an error field which indicate the user name already exists.