alx-files_manager

This project is a summary of this back-end trimester: authentication, NodeJS, MongoDB, Redis, pagination and background processing.

The objective is to build a simple platform to upload and view files:

• User authentication via a token
• List all files
• Upload a new file
• Change permission of a file
• View a file
• Generate thumbnails for images

You will be guided step by step for building it, but you have some freedoms of implementation, split in more files etc… (utils folder will be your friend)

Of course, this kind of service already exists in the real life - it’s a learning purpose to assemble each piece and build a full product.

Enjoy!

Resources

Read or watch:

• Node JS getting started
• Process API doc
• Express getting started
• Mocha documentation
• Nodemon documentation
• MongoDB
• Bull
• Image thumbnail
• Mime-Types
• Redis

Learning Objectives

At the end of this project, you are expected to be able to explain to anyone, without the help of Google:

• how to create an API with Express
• how to authenticate a user
• how to store data in MongoDB
• how to store temporary data in Redis
• how to setup and use a background worker

Provided files

package.json

Click to show/hide file contents

.eslintrc.js

Click to show/hide file contents

babel.config.js

Click to show/hide file contents

and…

Don’t forget to run $ npm install when you have the package.json

Tasks

0. Redis utils

mandatory

Inside the folder utils, create a file redis.js that contains the class RedisClient.

RedisClient should have:

• the constructor that creates a client to Redis:
  • any error of the redis client must be displayed in the console (you should use on('error') of the redis client)
• a function isAlive that returns true when the connection to Redis is a success otherwise, false
• an asynchronous function get that takes a string key as argument and returns the Redis value stored for this key
• an asynchronous function set that takes a string key, a value and a duration in second as arguments to store it in Redis (with an expiration set by the duration argument)
• an asynchronous function del that takes a string key as argument and remove the value in Redis for this key

After the class definition, create and export an instance of RedisClient called redisClient.

bob@dylan:~$ cat main.js
import redisClient from './utils/redis';

(async () => {
    console.log(redisClient.isAlive());
    console.log(await redisClient.get('myKey'));
    await redisClient.set('myKey', 12, 5);
    console.log(await redisClient.get('myKey'));

    setTimeout(async () => {
        console.log(await redisClient.get('myKey'));
    }, 1000*10)
})();

bob@dylan:~$ npm run dev main.js
true
null
12
null
bob@dylan:~$ 

1. MongoDB utils

Inside the folder utils, create a file db.js that contains the class DBClient.

DBClient should have:

• the constructor that creates a client to MongoDB:
  • host: from the environment variable DB_HOST or default: localhost
  • port: from the environment variable DB_PORT or default: 27017
  • database: from the environment variable DB_DATABASE or default: files_manager
• a function isAlive that returns true when the connection to MongoDB is a success otherwise, false
• an asynchronous function nbUsers that returns the number of documents in the collection users
• an asynchronous function nbFiles that returns the number of documents in the collection files

After the class definition, create and export an instance of DBClient called dbClient.

bob@dylan:~$ cat main.js
import dbClient from './utils/db';

const waitConnection = () => {
    return new Promise((resolve, reject) => {
        let i = 0;
        const repeatFct = async () => {
            await setTimeout(() => {
                i += 1;
                if (i >= 10) {
                    reject()
                }
                else if(!dbClient.isAlive()) {
                    repeatFct()
                }
                else {
                    resolve()
                }
            }, 1000);
        };
        repeatFct();
    })
};

(async () => {
    console.log(dbClient.isAlive());
    await waitConnection();
    console.log(dbClient.isAlive());
    console.log(await dbClient.nbUsers());
    console.log(await dbClient.nbFiles());
})();

bob@dylan:~$ npm run dev main.js
false
true
4
30
bob@dylan:~$ 

2. First API

Inside server.js, create the Express server:

• it should listen on the port set by the environment variable PORT or by default 5000
• it should load all routes from the file routes/index.js

Inside the folder routes, create a file index.js that contains all endpoints of our API:

• GET /status => AppController.getStatus
• GET /stats => AppController.getStats

Inside the folder controllers, create a file AppController.js that contains the definition of the 2 endpoints:

• GET /status should return if Redis is alive and if the DB is alive too by using the 2 utils created previously: { "redis": true, "db": true } with a status code 200
• GET /stats should return the number of users and files in DB: { "users": 12, "files": 1231 } with a status code 200
  • users collection must be used for counting all users
  • files collection must be used for counting all files

Terminal 1:

bob@dylan:~$ npm run start-server
Server running on port 5000
...

Terminal 2:

bob@dylan:~$ curl 0.0.0.0:5000/status ; echo ""
{"redis":true,"db":true}
bob@dylan:~$ 
bob@dylan:~$ curl 0.0.0.0:5000/stats ; echo ""
{"users":4,"files":30}
bob@dylan:~$ 

3. Create a new user

Now that we have a simple API, it’s time to add users to our database.

In the file routes/index.js, add a new endpoint:

• POST /users => UsersController.postNew

Inside controllers, add a file UsersController.js that contains the new endpoint:

POST /users should create a new user in DB:

• To create a user, you must specify an email and a password
• If the email is missing, return an error Missing email with a status code 400
• If the password is missing, return an error Missing password with a status code 400
• If the email already exists in DB, return an error Already exist with a status code 400
• The password must be stored after being hashed in SHA1
• The endpoint is returning the new user with only the email and the id (auto generated by MongoDB) with a status code 201
• The new user must be saved in the collection users:
  • email: same as the value received
  • password: SHA1 value of the value received

bob@dylan:~$ curl 0.0.0.0:5000/users -XPOST -H "Content-Type: application/json" -d '{ "email": "bob@dylan.com", "password": "toto1234!" }' ; echo ""
{"id":"5f1e7d35c7ba06511e683b21","email":"bob@dylan.com"}
bob@dylan:~$ 
bob@dylan:~$ echo 'db.users.find()' | mongo files_manager
{ "_id" : ObjectId("5f1e7d35c7ba06511e683b21"), "email" : "bob@dylan.com", "password" : "89cad29e3ebc1035b29b1478a8e70854f25fa2b2" }
bob@dylan:~$ 
bob@dylan:~$ 
bob@dylan:~$ curl 0.0.0.0:5000/users -XPOST -H "Content-Type: application/json" -d '{ "email": "bob@dylan.com", "password": "toto1234!" }' ; echo ""
{"error":"Already exist"}
bob@dylan:~$ 
bob@dylan:~$ curl 0.0.0.0:5000/users -XPOST -H "Content-Type: application/json" -d '{ "email": "bob@dylan.com" }' ; echo ""
{"error":"Missing password"}
bob@dylan:~$ 

4. Authenticate a user

In the file routes/index.js, add 3 new endpoints:

• GET /connect => AuthController.getConnect
• GET /disconnect => AuthController.getDisconnect
• GET /users/me => UserController.getMe

Inside controllers, add a file AuthController.js that contains new endpoints:

GET /connect should sign-in the user by generating a new authentication token:

• By using the header Authorization and the technique of the Basic auth (Base64 of the <email>:<password>), find the user associate to this email and with this password (reminder: we are storing the SHA1 of the password)
• If no user has been found, return an error Unauthorized with a status code 401
• Otherwise:
  • Generate a random string (using uuidv4) as token
  • Create a key: auth_<token>
  • Use this key for storing in Redis (by using the redisClient create previously) the user ID for 24 hours
  • Return this token: { "token": "155342df-2399-41da-9e8c-458b6ac52a0c" } with a status code 200

Now, we have a way to identify a user, create a token (= avoid to store the password on any front-end) and use this token for 24h to access to the API!

Every authenticated endpoints of our API will look at this token inside the header X-Token.

GET /disconnect should sign-out the user based on the token:

• Retrieve the user based on the token:
  • If not found, return an error Unauthorized with a status code 401
  • Otherwise, delete the token in Redis and return nothing with a status code 204

Inside the file controllers/UsersController.js add a new endpoint:

GET /users/me should retrieve the user base on the token used:

• Retrieve the user based on the token:
  • If not found, return an error Unauthorized with a status code 401
  • Otherwise, return the user object (email and id only)

bob@dylan:~$ curl 0.0.0.0:5000/connect -H "Authorization: Basic Ym9iQGR5bGFuLmNvbTp0b3RvMTIzNCE=" ; echo ""
{"token":"031bffac-3edc-4e51-aaae-1c121317da8a"}
bob@dylan:~$ 
bob@dylan:~$ curl 0.0.0.0:5000/users/me -H "X-Token: 031bffac-3edc-4e51-aaae-1c121317da8a" ; echo ""
{"id":"5f1e7cda04a394508232559d","email":"bob@dylan.com"}
bob@dylan:~$ 
bob@dylan:~$ curl 0.0.0.0:5000/disconnect -H "X-Token: 031bffac-3edc-4e51-aaae-1c121317da8a" ; echo ""

bob@dylan:~$ curl 0.0.0.0:5000/users/me -H "X-Token: 031bffac-3edc-4e51-aaae-1c121317da8a" ; echo ""
{"error":"Unauthorized"}
bob@dylan:~$ 

5. First file

In the file routes/index.js, add a new endpoint:

• POST /files => FilesController.postUpload

Inside controllers, add a file FilesController.js that contains the new endpoint:

POST /files should create a new file in DB and in disk:

• Retrieve the user based on the token:
  • If not found, return an error Unauthorized with a status code 401
• To create a file, you must specify:
  • name: as filename
  • type: either folder, file or image
  • parentId: (optional) as ID of the parent (default: 0 -> the root)
  • isPublic: (optional) as boolean to define if the file is public or not (default: false)
  • data: (only for type=file|image) as Base64 of the file content
• If the name is missing, return an error Missing name with a status code 400
• If the type is missing or not part of the list of accepted type, return an error Missing type with a status code 400
• If the data is missing and type != folder, return an error Missing data with a status code 400
• If the parentId is set:
  • If no file is present in DB for this parentId, return an error Parent not found with a status code 400
  • If the file present in DB for this parentId is not of type folder, return an error Parent is not a folder with a status code 400
• The user ID should be added to the document saved in DB - as owner of a file
• If the type is folder, add the new file document in the DB and return the new file with a status code 201
• Otherwise:
  • All file will be stored locally in a folder (to create automatically if not present):
    • The relative path of this folder is given by the environment variable FOLDER_PATH
    • If this variable is not present or empty, use /tmp/files_manager as storing folder path
  • Create a local path in the storing folder with filename a UUID
  • Store the file in clear (reminder: data contains the Base64 of the file) in this local path
  • Add the new file document in the collection files with these attributes:
    • userId: ID of the owner document (owner from the authentication)
    • name: same as the value received
    • type: same as the value received
    • isPublic: same as the value received
    • parentId: same as the value received - if not present: 0
    • localPath: for a type=file|image, the absolute path to the file save in local
  • Return the new file with a status code 201

bob@dylan:~$ curl 0.0.0.0:5000/connect -H "Authorization: Basic Ym9iQGR5bGFuLmNvbTp0b3RvMTIzNCE=" ; echo ""
{"token":"f21fb953-16f9-46ed-8d9c-84c6450ec80f"}
bob@dylan:~$ 
bob@dylan:~$ curl -XPOST 0.0.0.0:5000/files -H "X-Token: f21fb953-16f9-46ed-8d9c-84c6450ec80f" -H "Content-Type: application/json" -d '{ "name": "myText.txt", "type": "file", "data": "SGVsbG8gV2Vic3RhY2shCg==" }' ; echo ""
{"id":"5f1e879ec7ba06511e683b22","userId":"5f1e7cda04a394508232559d","name":"myText.txt","type":"file","isPublic":false,"parentId":0}
bob@dylan:~$
bob@dylan:~$ ls /tmp/files_manager/
2a1f4fc3-687b-491a-a3d2-5808a02942c9
bob@dylan:~$
bob@dylan:~$ cat /tmp/files_manager/2a1f4fc3-687b-491a-a3d2-5808a02942c9 
Hello Webstack!
bob@dylan:~$
bob@dylan:~$ curl -XPOST 0.0.0.0:5000/files -H "X-Token: f21fb953-16f9-46ed-8d9c-84c6450ec80f" -H "Content-Type: application/json" -d '{ "name": "images", "type": "folder" }' ; echo ""
{"id":"5f1e881cc7ba06511e683b23","userId":"5f1e7cda04a394508232559d","name":"images","type":"folder","isPublic":false,"parentId":0}
bob@dylan:~$
bob@dylan:~$ cat image_upload.py
import base64
import requests
import sys

file_path = sys.argv[1]
file_name = file_path.split('/')[-1]

file_encoded = None
with open(file_path, "rb") as image_file:
    file_encoded = base64.b64encode(image_file.read()).decode('utf-8')

r_json = { 'name': file_name, 'type': 'image', 'isPublic': True, 'data': file_encoded, 'parentId': sys.argv[3] }
r_headers = { 'X-Token': sys.argv[2] }

r = requests.post("http://0.0.0.0:5000/files", json=r_json, headers=r_headers)
print(r.json())

bob@dylan:~$
bob@dylan:~$ python image_upload.py image.png f21fb953-16f9-46ed-8d9c-84c6450ec80f 5f1e881cc7ba06511e683b23
{'id': '5f1e8896c7ba06511e683b25', 'userId': '5f1e7cda04a394508232559d', 'name': 'image.png', 'type': 'image', 'isPublic': True, 'parentId': '5f1e881cc7ba06511e683b23'}
bob@dylan:~$
bob@dylan:~$ echo 'db.files.find()' | mongo files_manager
{ "_id" : ObjectId("5f1e881cc7ba06511e683b23"), "userId" : ObjectId("5f1e7cda04a394508232559d"), "name" : "images", "type" : "folder", "parentId" : "0" }
{ "_id" : ObjectId("5f1e879ec7ba06511e683b22"), "userId" : ObjectId("5f1e7cda04a394508232559d"), "name" : "myText.txt", "type" : "file", "parentId" : "0", "isPublic" : false, "localPath" : "/tmp/files_manager/2a1f4fc3-687b-491a-a3d2-5808a02942c9" }
{ "_id" : ObjectId("5f1e8896c7ba06511e683b25"), "userId" : ObjectId("5f1e7cda04a394508232559d"), "name" : "image.png", "type" : "image", "parentId" : ObjectId("5f1e881cc7ba06511e683b23"), "isPublic" : true, "localPath" : "/tmp/files_manager/51997b88-5c42-42c2-901e-e7f4e71bdc47" }
bob@dylan:~$
bob@dylan:~$ ls /tmp/files_manager/
2a1f4fc3-687b-491a-a3d2-5808a02942c9   51997b88-5c42-42c2-901e-e7f4e71bdc47
bob@dylan:~$

6. Get and list file

In the file routes/index.js, add 2 new endpoints:

• GET /files/:id => FilesController.getShow
• GET /files => FilesController.getIndex

In the file controllers/FilesController.js, add the 2 new endpoints:

GET /files/:id should retrieve the file document based on the ID:

• Retrieve the user based on the token:
  • If not found, return an error Unauthorized with a status code 401
• If no file document is linked to the user and the ID passed as parameter, return an error Not found with a status code 404
• Otherwise, return the file document

GET /files should retrieve all users file documents for a specific parentId and with pagination:

• Retrieve the user based on the token:
  • If not found, return an error Unauthorized with a status code 401
• Based on the query parameters parentId and page, return the list of file document
  • parentId:
    • No validation of parentId needed - if the parentId is not linked to any user folder, returns an empty list
    • By default, parentId is equal to 0 = the root
  • Pagination:
    • Each page should be 20 items max
    • page query parameter starts at 0 for the first page. If equals to 1, it means it’s the second page (form the 20th to the 40th), etc…
    • Pagination can be done directly by the aggregate of MongoDB

bob@dylan:~$ curl 0.0.0.0:5000/connect -H "Authorization: Basic Ym9iQGR5bGFuLmNvbTp0b3RvMTIzNCE=" ; echo ""
{"token":"f21fb953-16f9-46ed-8d9c-84c6450ec80f"}
bob@dylan:~$ 
bob@dylan:~$ curl -XGET 0.0.0.0:5000/files -H "X-Token: f21fb953-16f9-46ed-8d9c-84c6450ec80f" ; echo ""
[{"id":"5f1e879ec7ba06511e683b22","userId":"5f1e7cda04a394508232559d","name":"myText.txt","type":"file","isPublic":false,"parentId":0},{"id":"5f1e881cc7ba06511e683b23","userId":"5f1e7cda04a394508232559d","name":"images","type":"folder","isPublic":false,"parentId":0},{"id":"5f1e8896c7ba06511e683b25","userId":"5f1e7cda04a394508232559d","name":"image.png","type":"image","isPublic":true,"parentId":"5f1e881cc7ba06511e683b23"}]
bob@dylan:~$
bob@dylan:~$ curl -XGET 0.0.0.0:5000/files?parentId=5f1e881cc7ba06511e683b23 -H "X-Token: f21fb953-16f9-46ed-8d9c-84c6450ec80f" ; echo ""
[{"id":"5f1e8896c7ba06511e683b25","userId":"5f1e7cda04a394508232559d","name":"image.png","type":"image","isPublic":true,"parentId":"5f1e881cc7ba06511e683b23"}]
bob@dylan:~$
bob@dylan:~$ curl -XGET 0.0.0.0:5000/files/5f1e8896c7ba06511e683b25 -H "X-Token: f21fb953-16f9-46ed-8d9c-84c6450ec80f" ; echo ""
{"id":"5f1e8896c7ba06511e683b25","userId":"5f1e7cda04a394508232559d","name":"image.png","type":"image","isPublic":true,"parentId":"5f1e881cc7ba06511e683b23"}
bob@dylan:~$

7. File publish/unpublish

In the file routes/index.js, add 2 new endpoints:

• PUT /files/:id/publish => FilesController.putPublish
• PUT /files/:id/publish => FilesController.putUnpublish

In the file controllers/FilesController.js, add the 2 new endpoints:

PUT /files/:id/publish should set isPublic to true on the file document based on the ID:

• Retrieve the user based on the token:
  • If not found, return an error Unauthorized with a status code 401
• If no file document is linked to the user and the ID passed as parameter, return an error Not found with a status code 404
• Otherwise:
  • Update the value of isPublic to true
  • And return the file document with a status code 200

PUT /files/:id/unpublish should set isPublic to false on the file document based on the ID:

• Retrieve the user based on the token:
  • If not found, return an error Unauthorized with a status code 401
• If no file document is linked to the user and the ID passed as parameter, return an error Not found with a status code 404
• Otherwise:
  • Update the value of isPublic to false
  • And return the file document with a status code 200

bob@dylan:~$ curl 0.0.0.0:5000/connect -H "Authorization: Basic Ym9iQGR5bGFuLmNvbTp0b3RvMTIzNCE=" ; echo ""
{"token":"f21fb953-16f9-46ed-8d9c-84c6450ec80f"}
bob@dylan:~$ 
bob@dylan:~$ curl -XGET 0.0.0.0:5000/files/5f1e8896c7ba06511e683b25 -H "X-Token: f21fb953-16f9-46ed-8d9c-84c6450ec80f" ; echo ""
{"id":"5f1e8896c7ba06511e683b25","userId":"5f1e7cda04a394508232559d","name":"image.png","type":"image","isPublic":false,"parentId":"5f1e881cc7ba06511e683b23"}
bob@dylan:~$
bob@dylan:~$ curl -XPUT 0.0.0.0:5000/files/5f1e8896c7ba06511e683b25/publish -H "X-Token: f21fb953-16f9-46ed-8d9c-84c6450ec80f" ; echo ""
{"id":"5f1e8896c7ba06511e683b25","userId":"5f1e7cda04a394508232559d","name":"image.png","type":"image","isPublic":true,"parentId":"5f1e881cc7ba06511e683b23"}
bob@dylan:~$ 
bob@dylan:~$ curl -XPUT 0.0.0.0:5000/files/5f1e8896c7ba06511e683b25/unpublish -H "X-Token: f21fb953-16f9-46ed-8d9c-84c6450ec80f" ; echo ""
{"id":"5f1e8896c7ba06511e683b25","userId":"5f1e7cda04a394508232559d","name":"image.png","type":"image","isPublic":false,"parentId":"5f1e881cc7ba06511e683b23"}
bob@dylan:~$ 

8. File data

In the file routes/index.js, add one new endpoint:

• GET /files/:id/data => FilesController.getFile

In the file controllers/FilesController.js, add the new endpoint:

GET /files/:id/data should return the content of the file document based on the ID:

• If no file document is linked to the ID passed as parameter, return an error Not found with a status code 404
• If the file document (folder or file) is not public (isPublic: false) and no user authenticate or not the owner of the file, return an error Not found with a status code 404
• If the type of the file document is folder, return an error A folder doesn't have content with a status code 400
• If the file is not locally present, return an error Not found with a status code 404
• Otherwise:
  • By using the module mime-types, get the MIME-type based on the name of the file
  • Return the content of the file with the correct MIME-type

bob@dylan:~$ curl 0.0.0.0:5000/connect -H "Authorization: Basic Ym9iQGR5bGFuLmNvbTp0b3RvMTIzNCE=" ; echo ""
{"token":"f21fb953-16f9-46ed-8d9c-84c6450ec80f"}
bob@dylan:~$ 
bob@dylan:~$ curl -XPUT 0.0.0.0:5000/files/5f1e879ec7ba06511e683b22/unpublish -H "X-Token: f21fb953-16f9-46ed-8d9c-84c6450ec80f" ; echo ""
{"id":"5f1e879ec7ba06511e683b22","userId":"5f1e7cda04a394508232559d","name":"myText.txt","type":"file","isPublic":false,"parentId":0}
bob@dylan:~$ 
bob@dylan:~$ curl -XGET 0.0.0.0:5000/files/5f1e879ec7ba06511e683b22/data -H "X-Token: f21fb953-16f9-46ed-8d9c-84c6450ec80f" ; echo ""
Hello Webstack!

bob@dylan:~$ curl -XGET 0.0.0.0:5000/files/5f1e879ec7ba06511e683b22/data ; echo ""
{"error":"Not found"}
bob@dylan:~$ 
bob@dylan:~$ curl -XPUT 0.0.0.0:5000/files/5f1e879ec7ba06511e683b22/publish -H "X-Token: f21fb953-16f9-46ed-8d9c-84c6450ec80f" ; echo ""
{"id":"5f1e879ec7ba06511e683b22","userId":"5f1e7cda04a394508232559d","name":"myText.txt","type":"file","isPublic":true,"parentId":0}
bob@dylan:~$ 
bob@dylan:~$ curl -XGET 0.0.0.0:5000/files/5f1e879ec7ba06511e683b22/data ; echo ""
Hello Webstack!

bob@dylan:~$

9. Image Thumbnails

Update the endpoint POST /files endpoint to start a background processing for generating thumbnails for a file of type image:

• Create a Bull queue fileQueue
• When a new image is stored (in local and in DB), add a job to this queue with the userId and fileId

Create a file worker.js:

• By using the module Bull, create a queue fileQueue
• Process this queue:
  • If fileId is not present in the job, raise an error Missing fileId
  • If userId is not present in the job, raise an error Missing userId
  • If no document is found in DB based on the fileId and userId, raise an error File not found
  • By using the module image-thumbnail, generate 3 thumbnails with width = 500, 250 and 100 - store each result on the same location of the original file by appending _<width size>

Update the endpoint GET /files/:id/data to accept a query parameter size:

• size can be 500, 250 or 100
• Based on size, return the correct local file
• If the local file doesn’t exist, return an error Not found with a status code 404

Terminal 3: (start the worker)

bob@dylan:~$ npm run start-worker
...

Terminal 2:

bob@dylan:~$ curl 0.0.0.0:5000/connect -H "Authorization: Basic Ym9iQGR5bGFuLmNvbTp0b3RvMTIzNCE=" ; echo ""
{"token":"f21fb953-16f9-46ed-8d9c-84c6450ec80f"}
bob@dylan:~$ 
bob@dylan:~$ python image_upload.py image.png f21fb953-16f9-46ed-8d9c-84c6450ec80f 5f1e881cc7ba06511e683b23
{'id': '5f1e8896c7ba06511e683b25', 'userId': '5f1e7cda04a394508232559d', 'name': 'image.png', 'type': 'image', 'isPublic': True, 'parentId': '5f1e881cc7ba06511e683b23'}
bob@dylan:~$ ls /tmp/files_manager/
2a1f4fc3-687b-491a-a3d2-5808a02942c9   51997b88-5c42-42c2-901e-e7f4e71bdc47   6dc53397-8491-4b7c-8273-f748b1a031cb   6dc53397-8491-4b7c-8273-f748b1a031cb_100   6dc53397-8491-4b7c-8273-f748b1a031cb_250    6dc53397-8491-4b7c-8273-f748b1a031cb_500
bob@dylan:~$ 
bob@dylan:~$ curl -XGET 0.0.0.0:5000/files/5f1e8896c7ba06511e683b25/data -so new_image.png ; file new_image.png
new_image.png: PNG image data, 471 x 512, 8-bit/color RGBA, non-interlaced
bob@dylan:~$ 
bob@dylan:~$ curl -XGET 0.0.0.0:5000/files/5f1e8896c7ba06511e683b25/data?size=100 -so new_image.png ; file new_image.png
new_image.png: PNG image data, 100 x 109, 8-bit/color RGBA, non-interlaced
bob@dylan:~$ 
bob@dylan:~$ curl -XGET 0.0.0.0:5000/files/5f1e8896c7ba06511e683b25/data?size=250 -so new_image.png ; file new_image.png
new_image.png: PNG image data, 250 x 272, 8-bit/color RGBA, non-interlaced
bob@dylan:~$

10. Tests!

Of course, a strong and stable project can not be good without tests.

Create tests for redisClient and dbClient.

Create tests for each endpoints:

• GET /status
• GET /stats
• POST /users
• GET /connect
• GET /disconnect
• GET /users/me
• POST /files
• GET /files/:id
• GET /files (don’t forget the pagination)
• PUT /files/:id/publish
• PUT /files/:id/unpublish
• GET /files/:id/data

11. New user - welcome email

Update the endpoint POST /users endpoint to start a background processing for sending a “Welcome email” to the user:

• Create a Bull queue userQueue
• When a new user is stored (in DB), add a job to this queue with the userId

Update the file worker.js:

• By using the module Bull, create a queue userQueue
• Process this queue:
  • If userId is not present in the job, raise an error Missing userId
  • If no document is found in DB based on the userId, raise an error User not found
  • Print in the console Welcome <email>!

In real life, you can use a third party service like Mailgun to send real email. These API are slow, (sending via SMTP is worst!) and sending emails via a background job is important to optimize API endpoint.