backend-wizards-stage1

String Analyzer API

A RESTful API service that analyzes strings and stores their computed properties including length, palindrome detection, unique character count, word count, SHA-256 hash, and character frequency mapping.

Features

• ✅ Create and analyze strings with automatic property computation
• ✅ Retrieve specific strings by value
• ✅ Filter strings using multiple query parameters
• ✅ Natural language query support
• ✅ Delete strings from the system
• ✅ SHA-256 hash-based unique identification
• ✅ Comprehensive error handling

Tech Stack

• Runtime: Node.js (v18+)
• Framework: Express.js
• Storage: In-memory (Map data structure)
• Deployment: Railway / Heroku / AWS

API Endpoints

1. Create/Analyze String

POST /strings
Content-Type: application/json

{
  "value": "string to analyze"
}

Response (201 Created):

{
  "id": "sha256_hash_value",
  "value": "string to analyze",
  "properties": {
    "length": 17,
    "is_palindrome": false,
    "unique_characters": 12,
    "word_count": 3,
    "sha256_hash": "abc123...",
    "character_frequency_map": {
      "s": 2,
      "t": 3,
      "r": 2
    }
  },
  "created_at": "2025-08-27T10:00:00Z"
}

2. Get Specific String

GET /strings/{string_value}

3. Get All Strings with Filtering

GET /strings?is_palindrome=true&min_length=5&max_length=20&word_count=2&contains_character=a

Query Parameters:

• is_palindrome: boolean (true/false)
• min_length: integer
• max_length: integer
• word_count: integer
• contains_character: single character

4. Natural Language Filtering

GET /strings/filter-by-natural-language?query=all%20single%20word%20palindromic%20strings

Example Queries:

• "all single word palindromic strings"
• "strings longer than 10 characters"
• "palindromic strings that contain the first vowel"
• "strings containing the letter z"

5. Delete String

DELETE /strings/{string_value}

Local Setup

Prerequisites

• Node.js (v18 or higher)
• npm or yarn

Installation

1. Clone the repository

git clone https://github.com/Olu433/string-analyzer-api 
cd string-analyzer-api 

2. Install dependencies

npm install

3. Run the server

# Development mode with auto-reload
npm run dev

# Production mode
npm start

The server will start on http://localhost:3000 by default.

Environment Variables

Create a .env file (optional):

PORT=3000

Testing the API

Using cURL

Create a string:

curl -X POST http://localhost:3000/strings \
  -H "Content-Type: application/json" \
  -d '{"value": "racecar"}'

Get a string:

curl http://localhost:3000/strings/racecar

Get all strings with filters:

curl "http://localhost:3000/strings?is_palindrome=true&word_count=1"

Natural language query:

curl "http://localhost:3000/strings/filter-by-natural-language?query=all%20single%20word%20palindromic%20strings"

Delete a string:

curl -X DELETE http://localhost:3000/strings/racecar

Using Postman

1. Import the API endpoints into Postman
2. Set the base URL to http://localhost:3000
3. Test each endpoint with sample data

Deployment

Railway Deployment

1. Create a Railway account at railway.app

2. Install Railway CLI:

npm install -g @railway/cli

3. Login and deploy:

railway login
railway init
railway up

4. Get your deployment URL:

railway domain

Alternative: Heroku Deployment

1. Create a Heroku account at heroku.com

2. Install Heroku CLI and login:

heroku login

3. Create and deploy:

heroku create your-app-name
git push heroku main

Project Structure

string-analyzer-api/
├── server.js           # Main application file
├── package.json        # Dependencies and scripts
├── .gitignore         # Git ignore rules
└── README.md          # This file

Error Handling

The API returns appropriate HTTP status codes:

• 200 OK: Successful GET request
• 201 Created: Successful POST request
• 204 No Content: Successful DELETE request
• 400 Bad Request: Invalid request parameters
• 404 Not Found: Resource not found
• 409 Conflict: Resource already exists
• 422 Unprocessable Entity: Invalid data type

Dependencies

• express: Web framework for Node.js
• cors: Enable CORS for cross-origin requests
• crypto: Built-in Node.js module for SHA-256 hashing

Development

For development with auto-reload:

npm run dev

Notes

• This implementation uses in-memory storage. Data will be lost on server restart.
• For production, consider using a database (PostgreSQL, MongoDB, etc.)
• The API supports URL-encoded string values in GET/DELETE requests
• Natural language parsing supports common patterns but may need extension for complex queries

Author

Awe Caleb

License

MIT