Multithreaded HTTP Server in C++

A low-level HTTP server developed in C++ following the principles of Beej's Guide to Network Programming. This project explores the inner workings of the HTTP protocol, POSIX socket management, and concurrency using multithreading.

About the Project

This project implements a web server capable of handling real-time requests from a browser. [cite_start]It supports serving static files (HTML, CSS, images) and processing user-submitted data via GET and POST methods.

Main Objectives:

• Understand the lifecycle of a server socket: getaddrinfo, socket, bind, listen, and accept.
• Implement real concurrency using std::thread to serve multiple devices (mobile, PC, etc.) simultaneously without blocking the main loop.
• Manually parse HTTP headers and extract data from the request body.

The architecture uses an HttpServer class to manage the port listener, while each accepted connection is delegated to an independent worker thread using detach().

Technologies

• Language: C++17
• Networking API: POSIX Sockets (sys/socket.h)
• Concurrency: ISO C++ Threads (<thread>)
• Compiler: g++

How to Build and Run

Prerequisites

Ensure you are on a Unix-like environment (Linux or macOS) with g++ installed.

Linux Dependencies (Debian/Ubuntu)

sudo apt-get install g++

Compiling & Running

g++ main.cpp server.cpp -o httpserver
./httpserver <port>

example: ./httpserver 8080

• Reminder: Ports from 0 to 1023 may be blocked by the OS and need admin/root permissions.

• You can access the server at http://localhost:8080

Static Files

• Path: / or /index.html
• Description: Serves the main HTML interface. It includes the CSS styling and the interactive form used to test POST requests.
• Method: GET

Echo Service

• Path: /api/echo
• Description: A diagnostic tool that returns the entire raw HTTP request sent by the client.It is wrapped in <pre> tags to preserve formatting.
• Method: GET

User-Agent Inspector

• Path: /api/user-agent
• Description: Parses the request headers and extracts the User-Agent string, identifying which browser or tool is accessing the server.
• Method: GET

Personal Salute

• Path: /api/salute
• Description: Greets the user based on URL query parameters.
• Example: /api/salute?name=John&age=38
• Output: Displays a header with "Hello John! Your age is: 38".
• Method: GET

Project Structure

📁 Project
├── 📄 main.cpp        # Entry point: handles CLI arguments and starts the server loop
├── 📄 server.cpp      # Implementation of routing logic, GET/POST handling, and Sockets
├── 📄 server.hpp      # HttpServer class definition and data structures
├── 📄 index.html      # Frontend interface with a POST form for testing

Reminder

This project is under development and was made only for learning porpouses, this code should not be used in any place that needs a real HTTP server since it doesnt have security measures yet. I will revisit this project on and so on to improving it when i have the necessity to learn new things related to that.