Number Classification API

Overview

This is a simple REST API written in Go using the Gorilla Mux router. The API allows users to classify numbers based on various properties such as being an Armstrong number, even/odd, prime, or perfect. It also integrates CORS middleware to handle cross-origin requests.

---

Features

• Classifies numbers based on mathematical properties.
• Handles user input and provides error messages for invalid inputs.
• Implements CORS support to allow cross-origin requests.
• Uses Gorilla Mux for routing.

---

Technologies Used

• Go (Golang) - The main programming language.
• Gorilla Mux - Router for handling API routes.
• JSON Encoding/Decoding - To format API responses.
• Net/HTTP - Standard Go package for handling HTTP requests.
• CORS Middleware - Custom middleware to allow cross-origin requests.

---

Installation

Prerequisites

Ensure you have the following installed:

• Go (latest stable version)

Clone the Repository

git clone https://github.com/yourusername/numbers-api.git
cd numbers-api

Install Dependencies

go mod tidy

---

Running the API

Start the Server

go run main.go

The server will start on port 3000.

---

API Endpoints

Classify Number

Endpoint: GET /api/classify-number?number={value}

Request Example

curl -X GET "http://localhost:3000/api/classify-number?number=371"

Response Example

{
  "number": 371,
  "is_prime": false,
  "is_perfect": false,
  "properties": ["armstrong", "odd"]
}

Error Handling

If an invalid number is provided:

{
  "number": "alphabet",
  "error": true
}

---

CORS Handling

This API supports CORS to allow requests from different origins. The middleware is applied globally.

CORS Middleware Implementation

func corsMiddleware(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        w.Header().Set("Access-Control-Allow-Origin", "*")
        w.Header().Set("Access-Control-Allow-Methods", "GET, OPTIONS")
        w.Header().Set("Access-Control-Allow-Headers", "Content-Type")

        if r.Method == "OPTIONS" {
            w.WriteHeader(http.StatusNoContent)
            return
        }

        next.ServeHTTP(w, r)
    })
}

---

Deployment

Run as a Binary

go build -o classify-number
./classify-number

Contributing

Feel free to contribute by forking the repo and submitting a pull request.

---

License

This project is licensed under the MIT License.