Comp 2322 Computer Networking Project: A Multi-thread Web Server

Student Information

• Name: LI Jianxi
• Student ID: 24109859d
• Course: COMP2322 Computer Networking
• Date: April 2026

Project Overview

This project implements a multi-threaded web server in Python that handles HTTP requests from web browsers or other client programs. The server supports concurrent connections, various HTTP methods, multiple response status codes, and features like persistent connections and conditional requests.

Features Implemented

Core Features

• ✅ Multi-threaded architecture – each request handled in a separate thread
• ✅ GET method support for text and image files
• ✅ HEAD method support
• ✅ HTTP persistent connections (keep-alive) and non-persistent connections (close)
• ✅ Last-Modified and If-Modified-Since header handling

Response Status Codes

Status Code	Description	Status
200 OK	Request successful	✅
304 Not Modified	File not modified since last request	✅
400 Bad Request	Malformed request syntax	✅
403 Forbidden	Access denied (directory listing, path traversal)	✅
404 Not Found	Requested file does not exist	✅

Security Features

• Path traversal attack prevention
• File permission checking
• Directory listing disabled

Requirements

Prerequisites

• Python 3.12.8 or higher
• No additional packages required (uses only standard library)

Supported Platforms

• Windows
• Linux
• macOS

Installation

1. Clone or download the project files

project/
├── MyWebServer.py
├── MyHTTPRequest.py
├── MyHTTPResponse.py
├── server_main.py
├── www/
│ ├── empty_dir (using to test 403 forbidden)
│ ├── index.html
│ ├── test.txt
│ └── test.jpg
└── server.log (auto-generated)

2. No compilation needed – Python is an interpreted language

Usage

Starting the Server

Basic usage (default settings):

python server_main.py

Default: http://127.0.0.1:8080, serving files from ./www

Custom host and port:

python server_main.py --host 0.0.0.0 --port 8888

Custom root directory:

python web_server.py --root /path/to/your/files

Testing the Server

(Supposing that the host and port of the server is 127.0.0.1 and 8080) 1. Using a Web Browser Open your browser and navigate to:

• http://127.0.0.1:8080/ – Home page with test links

• http://127.0.0.1:8080/test.txt – Text file

• http://127.0.0.1:8080/test.jpg – Image file

2. Using curl (Recommended for testing)

GET requests:

# Basic GET
curl http://127.0.0.1:8080/test.txt

# Verbose output (shows headers)
curl -v http://127.0.0.1:8080/test.txt

# Download and save file
curl -o downloaded.txt http://127.0.0.1:8080/test.txt

HEAD requests:

# Get headers only
curl -I http://127.0.0.1:8080/test.txt

Test 304 Not Modified:

# Get file info first to see Last-Modified time
curl -I http://127.0.0.1:8080/test.txt

# Use future date to get 304
curl -v -H "If-Modified-Since: Tue, 01 Jan 2030 00:00:00 GMT" http://127.0.0.1:8080/test.txt

Test 404 Not Found:

curl -v http://127.0.0.1:8080/nonexistent.html

Test 403 Forbidden:

curl -v http://127.0.0.1:8080/empty_dir/

Test 400 Bad Request:

# Send malformed request
curl -v -X "" http://127.0.0.1:8080/

Server Output Example

When running, the server displays detailed information:

Server started on 127.0.0.1:8080
Serving files from: C:\project\www
Press Ctrl+C to stop the server

🔌 New connection from 127.0.0.1:63070

================================================================================
📥 NEW REQUEST
================================================================================
⏰ Time:     2026-03-21 19:55:30
🌐 Client:   127.0.0.1:63070
📋 Method:   GET
📁 Path:     /test.txt
🔧 Version:  HTTP/1.1

📎 Headers:
   Host: 127.0.0.1:8080
   User-Agent: curl/8.18.0
   Connection: keep-alive

Serving file: C:\project\www\test.txt

📤 RESPONSE:
   Status: 200 OK
   Size: 49 bytes
   Type: text/plain
================================================================================
✅ Response: 200 OK
🔌 Connection closed from 127.0.0.1:63070

Log File

The server maintains a log file server.log with the following format:

2026-03-21 19:55:30 - 127.0.0.1/127.0.0.1 - 2026-03-21 19:55:30 - GET /test.txt - Request Received
2026-03-21 19:55:30 - 127.0.0.1/127.0.0.1 - 2026-03-21 19:55:30 - GET /test.txt - 200 OK

Architecture

Class Structure

Class	Purpose
HTTPRequest	Parses incoming HTTP requests, extracts method, path, headers
HTTPResponse	Builds HTTP responses with proper status codes and headers
WebServer	Main server class handling connections, threading, and file serving

Request Flow

1. Client connects → Server accepts in main thread

2. New thread created → handle_client() processes the connection

3. receive_request() reads HTTP request

4. HTTPRequest parses the request

5. process_request() routes to appropriate handler (GET/HEAD)

6. serve_file() locates file, checks permissions, builds response

7. Response sent back to client

8. Connection handled based on Connection header (keep-alive/close)

FAQ

Common Issues

Problem	Solution
Address already in use	Change port with --port 8888 or stop other services using port 8080
Permission denied	Use port > 1024 (e.g., 8080) or run as administrator
403 Forbidden	Check file permissions; ensure files are readable
404 Not Found	Verify file exists in www directory
Slow responses	Check if server is running; verify no firewall blocking

Port 80 Note

This server uses port 8080 by default instead of port 80 because:

• Port 80 is often occupied by other web servers (IIS, Apache, etc.)

• Ports below 1024 require administrator privileges on most systems

Acknowledgments

• Python socket programming documentation

• HTTP/1.1 RFC 2616 specification