README.md

Cheatsheet

• ✅ Domain (Entity + Value Object)
  • Business Rules (Pure english)
• ✅ Application (Use Case + Port)
• ✅ Infrastructure (Fake Repository)
• ✅ Presentation (Simple controller function)

Problem

Build a minimal Clean Architecture setup for creating a user with validation and repository storage.

Solution

Sequence

EPUIC

Development sequence must be like this

Entity -> Port -> Usecase -> Infrastructure -> Controller

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1) Entity

Business Rules:

• Entities

1. User has an ID
2. User has a phone number
3. User has a sex
4. User has a role
5. User has an age

• Value Objects

1. ID is a sequencial integer
2. PhoneNumber is a 10 digit field
3. Sex is male or female
4. Role can be admin/user/guest
5. Age is an integer from 0 to 120

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2) Port

• Port: UserRepository is an interface which specify user's model behaviour without the implementation. e.g. save(user) or findById(id)

• UseCase: CreateUser is an usecase which use the UserRepository's methods to add some functionalities on domain area.

Ports (Repositories) in fact are an interface between the Usecases and Entities

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3) Infrastructure

MongoUserRepository in fact implements the UserRepository methods. The UserRepository specifies WHAT to do and MongoUserRepository specifies HOW to do it with MongoDB.

You can swap MongoDB for PostgreSQL, MySQL, or an in-memory store without causing any change in application or domain layer.

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4) Presentation

createUserController connects the framework to the CreateUser Usecase so Controllers use the UseCases to implement their functionality

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5) Aggregation (main.ts)

1. Get DB client (e.g. MongoClient)
2. Create infrastructure repo (MongoUserRepository)
3. Pass MongoUserRepository's instance to CreateUser UseCase (It's possible because that infrastructure repository implements port repository)
4. Pass the CreateUser UseCase to the createUserController
5. Controller execute the UseCase

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🚀 Setup

Prerequisites

• Node.js 18+ (or use nvm)
• MongoDB running on localhost:27017

Installation

1. Navigate to the node directory:

cd node

2. Install dependencies:

npm install

3. Run the server:

npm start

The server will start on http://localhost:3000

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🧪 Testing with cURL

Create User

Basic Request

curl -X POST http://localhost:3000/create_user \
  -H "Content-Type: application/json" \
  -d '{
    "phone_number": "1234567890",
    "role": "user",
    "age": 25,
    "sex": "male"
  }'

One-liner

curl -X POST http://localhost:3000/create_user -H "Content-Type: application/json" -d '{"phone_number":"1234567890","role":"user","age":25,"sex":"male"}'

Create Admin User

curl -X POST http://localhost:3000/create_user \
  -H "Content-Type: application/json" \
  -d '{
    "phone_number": "9876543210",
    "role": "admin",
    "age": 30,
    "sex": "female"
  }'

Create Guest User

curl -X POST http://localhost:3000/create_user \
  -H "Content-Type: application/json" \
  -d '{
    "phone_number": "5555555555",
    "role": "guest",
    "age": 18,
    "sex": "male"
  }'

Validation Error Examples

Invalid Phone Number (not 10 digits)

curl -X POST http://localhost:3000/create_user \
  -H "Content-Type: application/json" \
  -d '{
    "phone_number": "123",
    "role": "user",
    "age": 25,
    "sex": "male"
  }'

Expected Response: 400 Bad Request

Invalid Age (over 120)

curl -X POST http://localhost:3000/create_user \
  -H "Content-Type: application/json" \
  -d '{
    "phone_number": "1234567890",
    "role": "user",
    "age": 150,
    "sex": "male"
  }'

Expected Response: 400 Bad Request

Invalid Age (negative)

curl -X POST http://localhost:3000/create_user \
  -H "Content-Type: application/json" \
  -d '{
    "phone_number": "1234567890",
    "role": "user",
    "age": -5,
    "sex": "male"
  }'

Expected Response: 400 Bad Request

Invalid Role

curl -X POST http://localhost:3000/create_user \
  -H "Content-Type: application/json" \
  -d '{
    "phone_number": "1234567890",
    "role": "invalid_role",
    "age": 25,
    "sex": "male"
  }'

Expected Response: 400 Bad Request

Invalid Sex

curl -X POST http://localhost:3000/create_user \
  -H "Content-Type: application/json" \
  -d '{
    "phone_number": "1234567890",
    "role": "user",
    "age": 25,
    "sex": "invalid"
  }'

Expected Response: 400 Bad Request

Phone Number with Non-Digit Characters

curl -X POST http://localhost:3000/create_user \
  -H "Content-Type: application/json" \
  -d '{
    "phone_number": "123456789a",
    "role": "user",
    "age": 25,
    "sex": "male"
  }'

Expected Response: 400 Bad Request

Pretty Print Response (with jq)

If you have jq installed, you can pretty-print the JSON response:

curl -X POST http://localhost:3000/create_user \
  -H "Content-Type: application/json" \
  -d '{
    "phone_number": "1234567890",
    "role": "user",
    "age": 25,
    "sex": "male"
  }' | jq .

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CC Architecture

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CC Implementation