HTTP Log File Analyzer

A TypeScript application that parses HTTP access logs and provides analytics about IP addresses and URL access patterns.

Features

• Counts unique IP addresses in the log file
• Identifies top 3 most visited URLs
• Identifies top 3 most active IP addresses
• Handles standard HTTP access log format
• Written in TypeScript with full type safety
• Includes unit tests

Prerequisites

• Node.js (v14 or higher)
• npm (v6 or higher)

Installation

1. Clone the repository:

git clone https://github.com/cryptoleek-eth/http-log-analyzer.git
cd http-log-analyzer

2. Install dependencies:

npm install

Usage

1. Build the project:

npm run build

2. Run the analyzer:

npm start

The analyzer will process the included sample log file (programming-task-example-data.log) and output:

• Number of unique IP addresses
• Top 3 most visited URLs with visit counts
• Top 3 most active IP addresses with request counts

Development

Project Structure

├── src/
│   ├── __tests__/          # Test files
│   ├── types/              # TypeScript interfaces
│   ├── utils/              # Utility classes
│   ├── services/           # Business logic
│   └── index.ts            # Application entry point
├── dist/                   # Compiled JavaScript files
└── programming-task-example-data.log    # Sample log file

Available Scripts

• npm run build - Compiles TypeScript to JavaScript
• npm start - Runs the compiled application
• npm test - Runs the test suite
• npm run dev - Runs the application in development mode using ts-node
• npx ts-node src/index.ts - Runs the application in development mode without building

Running Tests

npm test

Log File Format

The application expects log files in the following format:

Example:

177.71.128.21 - - [10/Jul/2018:22:21:28 +0200] "GET /url1 HTTP/1.1" 200 3574

Implementation Details

LogEntry Interface

Defines the structure for parsed log entries:

• ipAddress: Client IP address
• timestamp: Request timestamp
• method: HTTP method
• url: Requested URL
• protocol: HTTP protocol version
• statusCode: Response status code
• responseSize: Response size in bytes
• userAgent: Client user agent string

LogParser Class

Handles parsing of individual log lines using regex pattern matching.

LogAnalyzer Class

Provides analytics functionality:

• getUniqueIPCount(): Returns count of unique IP addresses
• getTopUrls(): Returns most frequently accessed URLs
• getTopIPs(): Returns most active IP addresses

Error Handling

• Invalid log entries are skipped during parsing
• File read errors are caught and reported
• Type safety is enforced throughout the application

Assumptions

1. Log file format follows the standard pattern
2. Log file is UTF-8 encoded
3. Memory usage is not a constraint (file is read entirely into memory)
4. URLs are case-sensitive
5. IP addresses are well-formed

License

This project is licensed under the MIT License - see the LICENSE file for details.