amjadelmahdy / image-processing-api

Express.js API with PostgreSQL DB integration that performs image processing and logs user's requests.

Image Processing API

Express.js API with PostgreSQL DB integration that performs image processing and logs user's requests.

This project Intensivly Demonstrates:

• Error Handling
• Testing (Integration, End to End, and unit testing)
• Strict typing using TypeScript & ESLint
• Logging
• DB integration
• DB Migration
• Upload & Download

Tech Choice

Postgres

• Availability: It is open source and free to use with any project
• Common: It is a relational, SQL database which is the most common type of database right now
• Popular and well-tested: Postgres is a viral database and a common choice among enterprise software
• Transferable: Because Postgres uses SQL, it is entirely transferable to working with a MySQL database or any other SQL database

Typescript & ESLint

• Strict: Maintain more error-prone code with no-implicit-any set to true.
• Reduce Errors: Using ESLint for syntax errors.

Winston

• Maintenance: Log unexpected server errors.

Table of Content

• Local Environment & Setup
• Run Locally
• Usage Examples
• API Referance
• DB Connection
• Running Tests
• Running Scripts
• Lessons Learned
• Challenges
• Tech Stack

Local Environment & Setup

To run this project, you will need to have the following on your system:

1. Node.js
2. PostgreSQL - Docker image or locally installed. There is docker-compose.yml already configured for you
3. DBeaver Community or your favorite SQL editor to monitor DB. Alternatively, you can use the psql terminal as documented here DB Connection
4. .env file with the following environment variables:
   

   POSTGRES_HOST=127.0.0.1
   POSTGRES_USER=nsipapi
   POSTGRES_DB=ipapi
   POSTGRES_TEST_DB=ipapi_test
   POSTGRES_PASSWORD=password123
   ENV=dev

Run Locally

1. Clone the project

  git clone https://github.com/amjadelmahdy/image-processing-api.git

2. Go to the project directory

  cd image-processing-api

3. Install packages

  npm install

4. Initiate PostgreSQL container

    docker-compose up

5. Run migrations

    npx db-migrate up

6. Start the server

    npm run start

Usage/Examples

API could be used through Postman or frontend http://localhost:3000/
Both are solid ways to display the HTTP Request & Response alongside the status code - message

Frontend UI

Postman

When using Postman make sure to use form-data as follows:

DBeaver Community

Using DBeaver Community to query the DB

Tip

Starter Status: On-Hold
Unexpected Errors: Logged inside logs/file-log-error.log

API Reference

Routes

Route	Method	Description
/	GET	Root - Home Page
/image	GET	Get an Image
/download	GET	Download an Image
/optimize	POST	Upload and Optimize an Image

Home Page

  GET /

Get Image

  GET /image/${image_name}

Parameter	Type	Description
image_name	string	Required. Name of the image to fetch

Download Image

  GET /download/${image_name}

Parameter	Type	Description
image_name	string	Required. Name of the image to fetch

Optimize Image

  POST /optimize

Property	Type	Description
width	number	Resize width
height	number	Resize height
quality	number	Compression quality
format	string	Convert format (png, jpeg, webp)
rotate	number	Degrees of rotation
blur	number	Sigma of the Gaussian mask
hue	number	Degree of hue rotation
saturation	number	Degree of saturation rotation
grayscale	boolean	Convert to black and white
text	string	Draw text on the image
red	number	Red color tint
green	number	Green color tint
blue	number	Blue color tint

Tip

• None of the properties are required, but you must provide at least one parameter inside req.body.
• The file has to be uploaded.
• Width & Height have to be provided together.
• Properties should have the same type.
• Must align with the accepted values table below.

Accepted Values

Property	Type	Max	Min
width	number	5000	1
height	number	5000	1
quality	number	100	1
format	string	(png, jpeg, webp)
rotate	number	360	1
blur	number	1000	1
hue	number	239	1
saturation	number	239	1
grayscale	boolean	true
text	string	20 characters
red	number	255	0
green	number	255	0
blue	number	255	0

DB Connection

Choose the way you're comfortable with

Via DBeaver Community

From navbar > Database > New Database Connection > PostgreSQL

Via psql Terminal

1. Connect to docker postgres-container bash using the following commands

  docker ps
  docker exec -it container_id bash
  psql -h 127.0.0.1 -U nsipapi -d ipapi

2. Now you can:

• List tables using \dt
  
• List databases using \l
  
• Connect to a database using \c database_name
  
• Use the following query: SELECT * FROM records;

Running Tests

To run tests, use the following command:

  npm run test

Important

Ensure POSTGRES_TEST_DB=ipapi_test, or change the name of the test-db in the test script inside package.json.

  "test": "db-migrate db:create test-db && db-migrate --env test up && cross-env ENV=test ts-node node_modules/jasmine/bin/jasmine && db-migrate db:drop test-db"

Explanation of Test Script

1. Creates a test database with a provided name
   
2. Sets the environment variable ENV=test to use the test configuration.
   
3. Run tests
   
4. Drops the test database to ensure a clean environment for each test run.

Important

If the test fails, you might need to drop the test database using the following command:
npx db-migrate db:drop test-db

Running Scripts

Script	Description
build	Compile the project to JavaScript
start	Start the built JavaScript project
dev:start	Start the TypeScript source project using ts-node & nodemon
lint	ESLint checks for syntax errors
lint:fix	ESLint checks and fixes syntax errors
prettier	Consistently organizes code using Prettier
prettier:fix	Run Prettier and ESLint fix together
test	Run tests before compiling using Jasmine and ts-node

Lessons Learned

• ESLint and Prettier: Make them work together using eslint-plugin-prettier.
• Compose Smaller Pieces: Build smaller components to reach the big picture.
• Jasmine Tests: Testing before compilation lacks support.

Tip

Solution: Use the test script ts-node node_modules/jasmine/bin/jasmine to run Jasmine with ts-node instead of a separate package like jasmine-ts.

Challenges

• Middleware Testing: Difficulty with mocking HTTP requests with Jasmine

• Uncaught Exceptions: Handling process.on "uncaughtException" at the app level rather than middleware.

Future implementations

• Pending requests: Modify and resubmit requests from the backend.

Tech Stack

Server: Node, Express, PostgreSQL, Multer, Sharp, DB-Migrate, Cross-Env, Dotenv, Winston