WebServer in C++

Minimal C++98 web server with non-blocking I/O (poll), a simple configuration parser, static file serving, basic error responses, and experimental CGI (Python) support. Developed by @nands93 and @amenesca for a university project. Educational and learning purpose only.

• Core entrypoint: srcs/main.cpp
• Server bootstrap: WebServer::configVServers, WebServer::initConnection
• Socket loop: Socket::startServer, Socket::acceptConnection, Socket::receiveRequest, Socket::sendResponse
• Request parsing: RequestParser::parse
• Response handling: Response::httpMethods, Response::handleGET, Response::handlePOST
• CGI handler: cgiHandler::postCgi, cgiHandler::configCgi, cgiHandler::createEnv
• Config parsing: ConfigParser::initConfig, ConfigParser::configServer, ConfigParser::treatLocation
• Virtual server + locations: VirtualServer, struct Location in the same header

Features

• Single-process, event-driven server using poll()
• Multiple clients, non-blocking sockets
• Nginx-like configuration syntax
• Static files from configured roots
• Basic GET and POST handling
• Basic error statuses for 400/404/405 (static HTML error pages exist but are not yet wired to responses)
• Experimental CGI (Python) invocation on .py URIs

Requirements

• Linux (uses poll, POSIX sockets, fcntl)
• g++ with C++98 support
• Python 3 at /usr/bin/python3 (used by CGI)
• Terminal (for build/run logs)

Build

make

Outputs binary: ./webserver

Targets are defined in Makefile.

Run

Run from the repository root (paths are relative).

• Default config:

./webserver

• Custom config:

./webserver ./conf/default.conf

The default config (conf/default.conf) listens on port 8080 and defines two servers (server_name localhost and server_name 127.0.0.1) on the same port. The active VirtualServer is selected by the Host header (without the port).

Examples:

• http://localhost:8080/ → serves data/www/index.html
• Host matching matters; e.g., curl with a specific Host:
  • curl -H "Host: localhost" http://127.0.0.1:8080/
  • curl -H "Host: 127.0.0.1" http://127.0.0.1:8080/

Note:

• Tilde paths are not expanded. The root ~/data/www/ in the second location of the default config will not resolve unless changed to an absolute path.
• Stop with Ctrl+C (handled in srcs/main.cpp).

Configuration

Syntax is parsed by ConfigParser.

Example: conf/default.conf

server {
  listen 8080
  server_name localhost
  body_size 1K

  location / {
    root data/www/
    index index.html
  }

  location /data {
    # Tilde is not expanded by the server; use an absolute path instead
    root /absolute/path/to/data/www/
    index index.html
  }
}

Recognized directives in server:

• listen, server_name, body_size, error_page, location

Inside location, see struct Location in VirtualServer:

• _locationPath, _root, _cgi_extension, _upload, _autoindex, _methods, _return, _index

Notes:

• Location matching is exact against the request URI (no prefix/longest-match logic).
• The selected VirtualServer is chosen by exact Host header match to server_name (port stripped).

Request Handling

• Requests are parsed by RequestParser:

  • Method, URI, version, headers, and body (for POST)
  • Host header parsing also extracts the port and stores Host without the port

• Responses are built by Response:

  • GET: Response::handleGET
    • If uri matches a location exactly, serves root + index[1]
    • Else, for single-location configs, serves root + uri
    • On success returns 200 text/html with file contents
    • On miss returns 404 (body currently not using custom error page)
  • POST: Response::handlePOST
    • If URI ends with .py, invokes CGI via cgiHandler::postCgi
    • Otherwise echoes a simple text/plain response if a body is present; else 400

• Static files are read in Response::readData

CGI

• Entry script: cgi-bin/index.py
• Trigger: POST to a URI ending with .py (e.g., /cgi-bin/index.py)
• Invoked by cgiHandler::postCgi using execve and environment from cgiHandler::createEnv

Current state:

• Experimental: child process executes Python, but the HTTP response body does not capture the script’s stdout back to the client. You will see a 200 OK with an empty body.
• The standalone test harness cgiHandler::configCgi (used by srcs/cgi/maincgi.cpp) demonstrates execution/redirection but is not wired into the main server path.

Ensure the script is executable. The form in data/www/index.html posts multipart/form-data to ../../cgi-bin/index.py.

Static Content and Error Pages

• Main page: data/www/index.html (includes a form to POST to CGI)
• Alternate pages: data/www/index_test.html, data/www/alan_index.html
• Error page templates (not automatically returned yet):
  • 400: data/error_pages/400.html
  • 404: data/error_pages/404.html
  • 405: data/error_pages/405.html

Quick Test

• GET home:

curl -i http://localhost:8080/

• POST to CGI (multipart):

curl -i -F "nome=Alice" -F "[email protected]" -F "imagem=@/path/to/image.png" http://localhost:8080/cgi-bin/index.py

• POST simple form data (echo path):

curl -i -d "hello=world" http://localhost:8080/

• Select a specific VirtualServer by Host:

curl -i -H "Host: localhost" http://127.0.0.1:8080/

Project Structure

• Core
  • srcs/main.cpp
  • WebServer, WebServer
  • Socket, Socket
• HTTP
  • RequestParser, RequestParser
  • Response, Response
• Configuration
  • ConfigParser, ConfigParser
  • VirtualServer, VirtualServer
• Clients
  • Client, Client
• CGI
  • cgiHandler, cgiHandler
  • cgi-bin/index.py
• Data
  • data/www, data/error_pages
• Includes
  • includes/Includes.hpp, includes/Defines.hpp, includes/Classes.hpp

Known Limitations

• Single listen socket; binds to the first configured VirtualServer port
• VirtualServer selection by exact Host header match only (no SNI, no IP-based)
• Location matching is exact against the request URI (no prefix/longest-match)
• Tilde (~) in paths is not expanded
• Some error responses currently miss body content
• No directory listing/autoindex
• No DELETE implementation yet
• CGI response body not returned to client (experimental plumbing)
• No TLS, no HTTP/1.1 persistent connections, no chunked encoding
• Minimal error handling and validation

Development Notes

• Signals: SIGINT triggers clean exit in srcs/main.cpp
• Non-blocking clients: set via fcntl in Socket::acceptConnection
• Buffering: