JSON Data Processing API

A lightweight, dependency-minimal Node.js API for processing JSON datasets. This service allows users to perform filtering, sorting, and aggregation operations on datasets provided via HTTP POST requests.

🚀 Features

• Data Filtering: Filter datasets based on specific key-value criteria.
• Data Sorting: Sort datasets by specific fields.
• Aggregation: Calculate Sum, Average, or Count for numeric fields.
• Input Validation: Robust JSON schema validation using ajv.
• Request Logging: Tracks request processing time and status codes.

🛠️ Installation

1. Clone the repository

   git clone <repository-url>
   cd json-api

2. Install dependencies

   npm install

3. Start the server

   npm test
   # OR
   node server.js

   The server will start on http://localhost:8000.

📡 API Usage

Health Check

GET /

{
  "message": "Server is running."
}

Process Data

POST /api/process

The API accepts a JSON body containing the dataset and the requested operation.

1. Filter Operation

Filters the dataset where fields match the provided criteria.

Request:

{
  "dataset": [
    { "id": 1, "role": "admin", "score": 10 },
    { "id": 2, "role": "user", "score": 20 },
    { "id": 3, "role": "admin", "score": 30 }
  ],
  "operation": "filter",
  "criteria": { "role": "admin" }
}

Response:

{
  "success": true,
  "operation": "filter",
  "result": [
    { "id": 1, "role": "admin", "score": 10 },
    { "id": 3, "role": "admin", "score": 30 }
  ]
}

2. Sort Operation

Sorts the dataset by the field specified in sortBy.

Request:

{
  "dataset": [
    { "name": "Alice", "age": 30 },
    { "name": "Bob", "age": 25 }
  ],
  "operation": "sort",
  "sortBy": "age"
}

Response:

{
  "success": true,
  "operation": "sort",
  "result": [
    { "name": "Bob", "age": 25 },
    { "name": "Alice", "age": 30 }
  ]
}

3. Aggregate Operation

Performs calculations (sum, average, count) on a targetField.

Request:

{
  "dataset": [
    { "item": "A", "price": 100 },
    { "item": "B", "price": 200 }
  ],
  "operation": "aggregate",
  "aggType": "average",
  "targetField": "price"
}

Response:

{
  "success": true,
  "operation": "aggregate",
  "result": {
    "average": 150
  }
}

📂 Project Structure

json-api/
├── services/
│   └── operations.js    # Core logic for filter, sort, aggregate
├── utils/
│   ├── bodyParser.js    # Request body parsing helper
│   ├── logger.js        # Request logging utility
│   └── validator.js     # AJV schema validation
├── server.js            # Main server entry point
├── package.json         # Project dependencies
└── README.md            # Project documentation

📝 Logging

Requests are logged to server.log (if configured) or console, tracking the method, URL, and processing duration.

🛡️ Error Handling

The API returns standard HTTP status codes:

• 200: Success
• 400: Validation Error or Unknown Operation
• 404: Endpoint Not Found
• 500: Internal Server Error