NestJS, MongoDB. RabbitMQ app with Typescript for managing users
The task is to implement an application that implements a nodeJS server API communicating with this: https://reqres.in/, using NestJS, RabbitMQ, MongoDB with Typescript.
The REST app should consist of:
- POST /api/users
On the request store the user entry in db. After the creation, send an email and rabbit event. Both can be dummy sending (no consumer needed).
- GET /api/user/{userId}
Retrieves data from https://reqres.in/api/users/{userId} and returns a user in JSON representation.
- GET /api/user/{userId}/avatar
Retrieves image by 'avatar' URL.
On the first request it should save the image as a plain file, stored as a mongodb entry with userId and hash. Return its base64-encoded representation.
On following requests should return the previously saved file in base64-encoded. representation (retrieve from db).
- DELETE /api/user/{userId}/avatar
Removes the file from the FileSystem storage.
Removes the stored entry from db.
First I decided to make a directory for the mailer service (src/mailer), while I had already defined the MongoDB
connection and the RabbitMQ service in the app.module.ts file.
I then created a src/user directory to store everything related to the user, except from their schema, which is
defined in a schema directory under src, aka src/schemas. The user module contains the user controller, user service,
as well as the user.module. Normally, it is a good practice to keep all the schemas in a separate directory, and,
although technically not needed for this sole-entity-project, I decided to keep it that way for the sake of consistency.
I decided to separate RabbitMQ as a separate service, as it is a good practice to keep the services separate from the
controllers and the business logic, especially when keeping in mind that we want anything to be added without a problem
and the code can scale infinitely. Therefore, I created a src/rabbit directory to store the RabbitMQ service and the
RabbitMQ module.
Developing the API, the second endpoint, GET /api/user/{userId}, refers to a userId that is not the same as the one
in the MongoDB database, thus is not alphanumeric, but rather, a number. That is why I kept this as a number, in order
to keep the API consistent with the Reqres API. On the other hand, the userId for the other two endpoints containing
a userId is the one from the MongoDB database, thus is alphanumeric. There was no need changing it to be an incremental
numerical, as it is not needed for the purpose of the endpoints and would only further complicate the code.
For the POST request I decided to add a USE_DUMMY_EMAIL environment variable, which, if set to true, will send a
dummy email to the user created. It is essentially logging to the console the hard-coded sender, aka me -
costopoulos.constantinos@gmail.com, the email of the user, the subject and the contents of the email through which the
user is welcomed to my platform. The email is sent using the nodemailer package, and the email is sent to the user's
email address, which is stored in the MongoDB database. In the future, I will implement that if the env variable is set
to false, the email will be actually sent from my email address to the user's email address, with the same content
as the dummy email. The implementation will be based on 2-step verification through Gmail and the OAuth2 protocol, so
an application-specific password will be used in order for my email data to be safe. As for the RabbitMQ event, it is
a dummy, emit event, as no consumer is needed.
########## Important Note so Far ##############
One could probably send an empty email by using MailerService from @nestjs-modules/mailer, and the whole configuration
would have been simpler. However, I wanted to actually send an email, and, instead of going through the tedious procedure
of setting up the OAuth2 protocol as I mentioned above, I decided to go with Mailtrap, which is a dummy email service.
Since either way I am not using a real email, I have my Mailtrap credentials hardcoded. The emails are actually being sent
as seen in the image below.
############################################
For getting the avatar of the user given their id, I check if the avatar element acquired when querying the database is
a url, it is the first call for this user, so save the image to the file system after having hashed it with the MD5
algorithm. The MD5 algorithm is used to hash the image, as it is a fast and reliable algorithm for hashing files. The
image is then saved in the media/avatars directory, with the name of the file being the hash of the image. The hash
is then stored in the MongoDB database, along with the user's id. The image is then returned in base64 encoding. If the
avatar element is not a url, then the image is already saved in the file system, so the image is read from the file system.
To verify that the image is encoded to base64 correctly, I created a image.b64 file under a the media/avatars/encoding-decoding-test
directory to store the base64 encoded image - the string essentially - and then I base64 -d image.b64 > image.jpg to
decode the image and see if it is the same as the original image. It is the same, so the encoding is correct.
For deleting the avatar of the user, I just delete the file from the file system and then delete the avatar element from the user in the MongoDB database.
Lastly, attention was paid to code formatting according to the eslint rules.
For details regarding testing, look in the Test section.
$ npm install# development
$ npm run start
# watch mode
$ npm run start:dev
# production mode
$ npm run start:prod# unit tests
$ npm run test
# e2e tests
$ npm run test:e2e
# test coverage
$ npm run test:covThe testing is of course done natively through jest, as it is the default testing framework for NestJS.
I added mocking for mocking as well as actual endpoint testing.
This is the result of npm run test:
npm run test
> Nestjs-User-Management@0.0.1 test
> jest
PASS src/app.controller.spec.ts
PASS src/mailer/mailer.service.spec.ts
PASS src/rabbit/rabbit.service.spec.ts
PASS src/user/user.controller.spec.ts
PASS src/utils/file-utils.spec.ts
(node:388390) [DEP0040] DeprecationWarning: The `punycode` module is deprecated. Please use a userland alternative instead.
(Use `node --trace-deprecation ...` to show where the warning was created)
PASS src/user/user.service.spec.ts
● Console
console.log
Dummy email content:
at MailerService.sendMail (mailer/mailer.service.ts:38:21)
console.log
From: "NestJS User Management" <costopoulos.constantinos@gmail.com>
at MailerService.sendMail (mailer/mailer.service.ts:39:21)
console.log
To: johndoe@email.com
at MailerService.sendMail (mailer/mailer.service.ts:40:21)
console.log
Subject: Welcome to NestJS User Management
at MailerService.sendMail (mailer/mailer.service.ts:41:21)
console.log
Text: Hello johndoe@email.com, welcome to our platform!
at MailerService.sendMail (mailer/mailer.service.ts:42:21)
Test Suites: 6 passed, 6 total
Tests: 17 passed, 17 total
Snapshots: 0 total
Time: 4.791 s, estimated 6 s
Ran all test suites.
This project is MIT licensed.