README.md

Stateless Microservice In Nodejs for creating image thumbnails

Important Note

Run this command before npm run dev or npm start

npm install -g swagger-ui-express nodemon eslint swagger express

ES6 is used throughout the code and Babel is used to transpile the code to Commonjs format

The following functionalities are implemented in

• Authentication
• Image Thumbnail Generation

Setup

The API requires latest LTS version of Node.js preferbably __v12.14.0__ of Nodejs

To get up and running:

1. Clone the repo.

git clone https://github.com/aashishpiitk/image-thumbnail-generator

2. cd into repo. Use the same directory name(below) if you do not change it.

cd image-thumbnail-generator

3. Setup the application by installing its dependencies with

npm install

4. Install the following packeges as glocal npm packages

npm install -g nodemon eslint swagger

5. Running the app in development mode

Run the command below from the application's root directory. The app gets up and running on port 3000 with

npm run dev

Access the server on http://localhost:3000/

6. Running the unit tests

Run the command below from the application's root directory.

npm run test

Swagger Docs

The API documentation is available in form of swagger docs at the end point

http://localhost:3000/api-docs/

Note

You can use try it out feature in each of the endpoints in the docs to perform the request to the server and fetch the response

Testing the API routes

(Preferbably with Postman)

Since this is mostly an API with post and patch requests, testing will be done with Postman

Authentication(Login and receiving the JWT token)

This is a mock authentication so you can pass in any username or password to login.

1. Set the request to POST and the url to http://localhost:3000/users/login
2. You will be setting 2 keys (for username and password).
   Set the username key to any name.(minimum 3 characters long)
   Set password to any password (minimum of 6 characters).

Send this info in the body of request

{
    "username": "aashishp",
    "password": "123456"
}

3. Hit Send. You will get a result in this format:

{
   "user": "aashishp",
   "authorized": true,
   "token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VybmFtZSI6ImRhd2Zlc2dyIiwiaWF0IjoxNTQ5MTI2OTgwLCJleHAiOjE1NDkxMzA1ODB9.ywbMXejRhwsxg9A3QRcgPbh7bq2DnPBNTL3h2yIpaiM"
}

Image Thumbnail Generation

This request contains a public image URL. It downloads the image, resizes to 50x50 pixels, and returns the resulting thumbnail's link

1. Set the request to POST and the url to http://localhost:3000/image/generate-thumbnail.
2. Set the key imageUrl to a public image url.

Send this info in the body of request

{
    "imageUrl": "https://homepages.cae.wisc.edu/~ece533/images/arctichare.png",
    "token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VybmFtZSI6ImRhd2Zlc2dyIiwiaWF0IjoxNTQ5MTI2OTgwLCJleHAiOjE1NDkxMzA1ODB9.ywbMXejRhwsxg9A3QRcgPbh7bq2DnPBNTL3h2yIpaiM"
}

3. The token generated earlier will be patched with the key.
4. At first, if JWT is missing or invalid then the request will be rejected otherwise,
5. Image will be downloaded and converted to a thumbnail of size 50x50 pixels with a sample result as below:

{
   "authorized": true
   "converted": true
   "imagePath": "http://localhost:3000/images/resized/60thumbnail.png",
}

6.Use ctrl+mouse click to click on the imagePath which opens the resized image in browser

Unit Testing

Unit testing is done using mochai = mocha + chai(asserion)

Linting

Linting is done using eslint + airbnb_config

Autoformatting is done using prettier

Transpiling

The ES6 code is not compatible with the LTS version of nodejs so I used Babel to transpile the ES6 code to CommonJs format

The tranpiled code can be obtained in a directory named dist in the root directory using the command npm run build

API Testing

Is done using Postman

Built With

• Node.js
• Express
• Mocha - For testing
• Babel - For transpiling