CppWebServer

A lightweight, modular, and extensible C++ HTTP/HTTPS server.
CppWebServer is built for serving static files securely and efficiently with support for essential HTTP methods, SSL/TLS encryption, multithreading, and content negotiation. Designed with modern C++17 practices and a modular architecture using CMake.

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Table of Contents

1. Features
2. Prerequisites
3. Project Structure
4. Building from Source
5. Configuration
6. Running the Server
7. Usage Examples
8. Error Handling
9. Content Negotiation
10. SSL/TLS (HTTPS) Support
11. Logging
12. Extending & Contributing
13. Roadmap & Future Work
14. License

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Features

• Sockets: Core TCP/IP support via BSD sockets (IPv4), with HTTP and HTTPS listeners.
• HTTP Support: GET, HEAD, OPTIONS methods; dynamic status and headers.
• Static Files: Serve from a customizable docRoot with MIME detection and index.html fallback.
• Concurrency: std::thread-based handling for each connection with thread-safe logging.
• Modularity: Individual components for sockets, HTTP, logging, config, SSL, etc.
• Custom JSON Config: Lightweight JSON parser for loading runtime parameters.
• HTTPS Support: Built-in SSL/TLS with OpenSSL.
• Error Responses: 400, 404, 405, 406, 500 with HTML messages.
• Content Negotiation: Honors Accept header for MIME type filtering.
• CMake Build System: Modern modular CMakeLists.txt.

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Prerequisites

• Compiler: C++17 (GCC ≥ 7, Clang ≥ 8)
• CMake: ≥ 3.10
• OpenSSL: Required for HTTPS

macOS

brew install cmake openssl pkg-config

Ubuntu/Debian

sudo apt update
sudo apt install -y build-essential cmake libssl-dev

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Project Structure

CppWebServer/
├── CMakeLists.txt
├── config.json
├── include/
│   ├── *.hpp                 # Component headers
├── src/
│   ├── *.cpp                 # Implementations + main.cpp
├── public/
│   ├── index.html
│   └── style.css

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Building from Source

git clone https://github.com/togunchan/CppWebServer.git
cd CppWebServer
mkdir build && cd build
cmake ..
make

Note (macOS OpenSSL):

cmake -DCMAKE_BUILD_TYPE=Release \
  -DOPENSSL_ROOT_DIR=/usr/local/opt/openssl \
  -DOPENSSL_INCLUDE_DIR=/usr/local/opt/openssl/include \
  -DOPENSSL_LIBRARIES=/usr/local/opt/openssl/lib ..

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Configuration

Sample config.json:

{
  "port": 8080,
  "sslPort": 8443,
  "docRoot": "./public",
  "maxThreads": 4
}

Values are parsed by a custom lightweight JSON parser. Missing or malformed files trigger detailed errors.

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Running the Server

1. Ensure server.crt and server.key are in place.
2. Launch the server:

./build/src/CppWebServer

Sample Output:

port: 8080
sslPort: 8443
docRoot: ./public
maxThreads: 4
Server listening on port 8080
Server listening on port 8443

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Usage Examples

curl -i http://localhost:8080/index.html          # 200 OK
curl -I http://localhost:8080/index.html          # HEAD
curl -X OPTIONS -i http://localhost:8080/index.html  # OPTIONS
curl -i http://localhost:8080/missing.html        # 404 Not Found
curl -X POST -i http://localhost:8080/index.html  # 405 Method Not Allowed
curl -H "Accept: image/png" -i http://localhost:8080/index.html  # 406 Not Acceptable

HTTPS Example:

curl -k https://localhost:8443/index.html

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Error Handling

Code	Description
400	Malformed HTTP request
404	File not found
405	Unsupported HTTP method
406	MIME type not acceptable
500	Internal server error

All errors return minimal HTML pages via sendErrorResponse().

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Content Negotiation

MIME matching from Accept header supports:

• */* → Accept all
• type/* → Accept all subtypes (e.g. text/*)
• type/subtype → Exact match

Fallback: */* if Accept is missing.

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SSL/TLS (HTTPS) Support

• Uses OpenSSL.
• Separate listener on sslPort.
• SSL handshake with SSL_accept().
• Handles encrypted reads/writes via SSL_read() / SSL_write().

To generate a self-signed certificate:

openssl req -x509 -newkey rsa:4096 -keyout server.key -out server.crt \
  -days 365 -nodes -subj "/CN=localhost"

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Logging

• Thread-safe logging via std::mutex.
• Output to std::cout.
• Future: log levels, file output, rotation.

void log(const std::string& msg) {
    std::lock_guard<std::mutex> lock(logMutex);
    std::cout << msg << std::endl;
}

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Extending & Contributing

1. Clone & Build

git clone https://github.com/togunchan/CppWebServer.git
cd CppWebServer
mkdir build && cd build
cmake ..
make

2. Feature Branch

git checkout -b feature/my-feature

3. Coding Guidelines

• 4-space indentation
• Braces on new lines
• Doxygen-style comments

4. Submit a PR

Push and open a Pull Request describing your changes.

Testing (Planned)

• Unit Testing: HttpParser, Config, getMimeType, isAcceptable
• Integration: Full server runs using curl, openssl, etc.
• CI: GitHub Actions or similar for automatic builds.

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Roadmap & Future Work

• Thread Pool
• HTTP Keep-Alive
• LRU Caching
• Gzip Compression
• Routing & Dynamic Content
• WebSocket Support
• HTTP/2 & HTTP/3
• Security Enhancements
• Let's Encrypt Integration
• Structured Logging & Metrics
• Complete Test Suite

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License

This project is licensed under the MIT License.
Feel free to use, modify, and distribute.

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Contact

Questions, feedback, ideas?