C HTTP/HTTPS Server 🔒

A lightweight, production-ready HTTP/1.1 server written in C with TLS/SSL support. Ideal for embedded systems, education, or as a foundation for web services.

Features:

• ✅ HTTPS with modern TLS 1.3/1.2
• 🔑 Certificate-based authentication
• 🚀 Multi-client concurrency (fork-based)
• 🛡️ Security headers (HSTS, CSP, X-Content-Type)
• 📁 Static file serving & directory listings

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📦 Installation

Prerequisites

• C compiler (gcc/clang)
• OpenSSL 3.x
• GNU Make

# Clone repository
git clone https://github.com/khantsithu/http-server-in-c.git
cd http-server-in-c

# Install OpenSSL (macOS/Homebrew)
brew install openssl

# Build (adjust OpenSSL paths in Makefile if needed)
make build

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🔧 Configuration

HTTPS Certificates

1. Development (self-signed):

   mkdir -p certs
   openssl req -x509 -newkey rsa:4096 -keyout certs/key.pem -out certs/cert.pem -days 365 -nodes

2. Production (Let’s Encrypt):

   certbot certonly --standalone -d yourdomain.com
   # Symlink to project certs/
   ln -s /etc/letsencrypt/live/yourdomain.com/ certs/production

Environment Variables

Variable	Default	Description
PORT	8080	HTTP port
HTTPS_PORT	8443	HTTPS port
SSL_CERT	certs/cert.pem	Certificate path
SSL_KEY	certs/key.pem	Private key path

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🚀 Usage

Start Server

# HTTP only
./server

# HTTPS (with certs)
./server --https

Example Requests

# Fetch HTML page
curl -k https://localhost:8443/

# Test security headers
curl -I https://localhost:8443/

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🛡️ Security Best Practices

• 🔒 Never commit certificate files (add to .gitignore)
• 🔄 Automate Let’s Encrypt renewal:

  certbot renew --quiet --post-hook "killall server && make run"

• 🚫 Use firewall rules to restrict port access
• 📈 Monitor with tools like fail2ban or nginx reverse proxy

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🧑💻 Contributing

1. Fork the repository
2. Create a feature branch (git checkout -b feat/amazing-feature)
3. Commit changes (git commit -m 'Add amazing feature')
4. Push to branch (git push origin feat/amazing-feature)
5. Open a Pull Request

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📄 License

Distributed under the MIT License. See LICENSE for details.

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🙏 Acknowledgments

• OpenSSL for TLS/SSL implementation
• Inspired by tinyhttp and libhv