README.md

This project has been created as part of the 42 curriculum by kikwasni, alraltse, korzecho

📌 Description

Webserv is a custom HTTP server written entirely in C++ 98 as part of the 42 curriculum.

The objective of this project is to build a fully functional, non-blocking web server from scratch, without using any external web server libraries. The server must handle multiple clients simultaneously using a single I/O multiplexing mechanism such as poll(), select(), epoll(), or kqueue().

The program is executed as: ./webserv [configuration_file]

This server is designed to:

• Parse and apply a configuration file inspired by NGINX
• Handle multiple ports and multiple server blocks
• Serve static websites
• Support file uploads
• Implement at least the GET, POST, and DELETE HTTP methods
• Execute CGI scripts (e.g. PHP or Python)
• Provide accurate HTTP status codes
• Return default error pages when necessary
• Remain fully non-blocking at all times
• Properly handle client disconnections
• Manage multiple simultaneous connections through a single event loop

The architecture is event-driven and built around non-blocking sockets. All socket I/O operations are performed only after readiness is confirmed through a single multiplexing call. The server must never hang indefinitely and must remain resilient under stress conditions.

Special attention is given to:

• Correct HTTP request parsing
• Header validation
• Chunked transfer decoding
• CGI communication through environment variables
• Proper file descriptor management
• Memory safety and resource cleanup

The configuration file allows:

• Defining interface and port pairs
• Setting default error pages
• Limiting client body size
• Configuring routes (allowed methods, redirections, root directories)
• Enabling/disabling directory listing
• Defining default index files
• Enabling file uploads
• Configuring CGI execution based on file extension

This project demonstrates low-level network programming, event-driven architecture, protocol handling, and system-level resource management in C++ 98.

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🛠️ Instructions

Compilation

The project is written in C++ 98. Use the provided Makefile to compile:

make

Available rules:

• make clean – remove object files
• make fclean – remove object and executable files
• make re – recompile everything

Execution

./webserv [path_to_configuration_file]

If no configuration file is provided, the server will attempt to load default.conf from the project root.

Testing

• Web Browser: http://localhost:8080 (or port defined in config)
• Curl:

curl -v http://localhost:8080

• Telnet: manually simulate raw HTTP requests

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⚙️ Configuration File

The configuration file defines server behavior and is inspired by NGINX. It allows hosting multiple virtual servers and defining rules per route.

Configurable options:

• Interfaces & Ports: define IP addresses and ports
• Client Limits: client_max_body_size for uploads
• Error Handling: custom HTML pages for HTTP errors (404, 500, etc.)
• Location Blocks:
  • Allowed HTTP methods
  • Root & index files
  • Autoindex (directory listing)
  • HTTP redirects (301/302)
  • CGI script execution based on file extension
  • Upload directory

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📚 Resources

Documentation & Articles

• Socket Programming in C++ (GeeksforGeeks) — comprehensive guide on socket concepts and usages
• Webserv — Building a Non-Blocking Web Server in C++ 98 (Medium) — article oriented on the 42 Webserv project

Video Tutorials

• Non-Blocking Sockets & I/O Multiplexing in C/C++ (YouTube) — tutorial explaining key concepts
• HTTP Server Concepts (YouTube) — video overview related to basic HTTP server mechanisms