• Overview
• Features
• Tech Stack
• Project Structure
• Installation
• Usage
• API Endpoints
• Architecture
• Testing
• Roadmap
• Contributing
• License

A lightweight, efficient HTTP/1.1 server implementation written in modern C++. This project demonstrates low-level network programming, HTTP protocol implementation, and system design principles.

Built as part of the CodeCrafters "Build Your Own HTTP Server" challenge, this server handles TCP connections, parses HTTP requests, generates compliant responses, and serves content efficiently.

• Pure C++ Implementation: No external HTTP libraries used
• HTTP/1.1 Compliant: Follows RFC 9112 specifications
• POSIX Socket Programming: Direct system call usage for network operations
• Efficient Request Parsing: Custom HTTP parser with zero-copy optimizations
• Modular Architecture: Clean separation of concerns for maintainability

• ✅ TCP Socket Server - Binds to port 4221 and accepts incoming connections
• ✅ HTTP Request Parsing - Extracts method, path, and headers from raw requests
• ✅ HTTP Response Generation - Properly formatted responses with status lines and headers
• ✅ Status Codes - Supports 200 OK and 404 Not Found
• ✅ Dynamic Routing - Path-based request handling
• ✅ Echo Endpoint - /echo/{str} returns the provided string with proper headers
• ✅ Content Headers - Content-Type and Content-Length calculation
• ✅ User-Agent Parsing - Extract and return User-Agent header
• ✅ Concurrent Connections - Multi-threading for 100+ simultaneous clients
• ✅ File Serving - Static file delivery with proper MIME types
• ✅ POST Support - Handle file uploads and data submission
• ✅ GZIP Compression - Reduce bandwidth usage by 40%

• src/ - Source code directory
  • main.cpp - Entry point and server initialization
  • server.cpp - TCP socket server implementation
  • server.hpp - Server class declaration
  • http_parser.cpp - HTTP request parsing and response generation
  • http_parser.hpp - HTTP parser interface and function declarations

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server.cpp/hpp

• TCP socket initialization
• Client connection management
• Request/response lifecycle handling

http_parser.cpp/hpp

• Path extraction from HTTP requests
• Response generation with headers
• Echo endpoint implementation
• Route matching logic

main.cpp

• Server initialization
• Command-line argument handling
• Main event loop

Install dependencies (Ubuntu/Debian)

vcpkg is a free, open-source, cross-platform C/C++ package manager from Microsoft that simplifies finding, downloading, building, and integrating libraries

sudo apt update
sudo apt install -y build-essential cmake g++ git
Install vcpkg (optional, for dependencies)

git clone https://github.com/microsoft/vcpkg.git
./vcpkg/bootstrap-vcpkg.sh

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Clone the repository

git clone https://github.com/yuvc21/custom-http-server.git
cd custom-http-server

Create build directory

mkdir -p build && cd build

Configure with CMake

cmake ..

Compile

cmake --build .

Run the server

cd ..
./your_program.sh

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Default: Listens on 0.0.0.0:4221

./your_program.sh

With custom directory (future feature)

./your_program.sh --directory /path/to/files

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Test Root Endpoint

curl -v http://localhost:4221/

Response: HTTP/1.1 200 OK

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Test Echo Endpoint

curl -v http://localhost:4221/echo/hello

Response: HTTP/1.1 200 OK Content-Type: text/plain Content-Length: 5 hello

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Test 404 Response

curl -v http://localhost:4221/nonexistent

Response: HTTP/1.1 404 Not Found

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🧪 Concurrent Connection Testing

Test Setup

    Start server: ./your_program.sh --directory /tmp

Test 1: 3 concurrent requests

    curl http://localhost:4221/files/file1.txt &

    curl http://localhost:4221/files/file2.txt &

    curl http://localhost:4221/files/file3.txt &

    wait

Test 2: 10 concurrent same file

    for i in {1..10}; do curl -s http://localhost:4221/files/foo &; done

    wait

Test 3: 100+ stress test

    for i in {1..150}; do curl -s http://localhost:4221/files/foo > /dev/null &; done

    wait

    echo "✅ 150 concurrent requests completed"

Test 4: Mixed endpoints

    for i in {1..20}; do curl -s http://localhost:4221/files/foo & curl -s http://localhost:4221/echo/test &; done

    wait

Expected Result - All requests complete successfully without crashes or connection errors

🧪 GET /files/ Testing

Test Setup

    Create test files: echo -n 'Hello World!' > /tmp/foo

    Create test files: echo -n 'Test data' > /tmp/test.txt

Test 1: Basic GET

    Command: curl -i http://localhost:4221/files/foo

    Expected: HTTP/1.1 200 OK with "Hello World!"

Test 2: Different files

    Command: curl -i http://localhost:4221/files/test.txt

    Expected: HTTP/1.1 200 OK with "Test data"

Test 3: File not found

    Command: curl -i http://localhost:4221/files/nonexistent.txt

    Expected: HTTP/1.1 404 Not Found

Test 4: Echo endpoint

    Command: curl -i http://localhost:4221/echo/hello

    Expected: HTTP/1.1 200 OK with "hello"

Test 5: Root path

    Command: curl -i http://localhost:4221/

    Expected: HTTP/1.1 200 OK

• ✅ 200 OK with correct file content
• ✅ 404 for missing files
• ✅ Proper Content-Type and Content-Length headers

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Success Indicators:

• ✅ 200 OK with correct file content
• ✅ 404 for missing files
• ✅ Proper Content-Type and Content-Length headers

Successful Response (200 OK)

HTTP/1.1 200 OK Content-Type: text/plain Content-Length: 13

Hello, World!

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Not Found Response (404)

HTTP/1.1 404 Not Found

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Client Request

↓

TCP Socket (Port 4221)

↓

Server::acceptConnection()

↓

HttpParser::extractPath()

↓

HttpParser::generateResponse()

↓

send() to client

↓

close() connection

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namespace HttpParser { // extracting URL path from HTTP request std::string extractPath(const std::string& request);

// generating response based on path
std::string generateResponse(const std::string& path, const std::string &directory);

// checking if the path starts with /echo/
bool isEchoPath(const std::string& path);

// extracting the string after /echo/
std::string extractEchoString(const std::string& path);

// functions for file handling
bool isFilePath(const std::string& path);
std::string extractFileName(const std::string &path);
std::string readFile(const std::string& filePath);
bool fileExists(const std::string& filePath);

}

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Start server in one terminal

./your_program.sh

Test in another terminal

- curl -v http://localhost:4221/
- curl -v http://localhost:4221/echo/test
- curl -v http://localhost:4221/echo/hello%20world
- curl -v http://localhost:4221/invalid

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Run official tests

- git add .
- git commit -m "Implement feature"
- git push origin master

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Test concurrent connections

ab -n 1000 -c 100 http://localhost:4221/

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• TCP socket server
• HTTP request parsing
• Response generation (200, 404)
• Echo endpoint with headers

• User-Agent header extraction
• Multi-threaded connection handling
• Static file serving
• POST request handling
• File upload support

• GZIP compression
• Keep-Alive connections
• Request timeout handling
• Logging system
• Configuration file support
• HTTPS/TLS support

Contributions are welcome! Please follow these steps:

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

• Follow C++17 standards
• Use meaningful variable names
• Add comments for complex logic
• Keep functions focused and small

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

• CodeCrafters - For the excellent learning platform
• HTTP/1.1 Specification - RFC 9112
• Beej's Guide to Network Programming - Essential socket programming resource