Proxy HTTP Server — CC4303

TCP-based HTTP server with two modes:

• Simple server
• HTTP proxy with filtering and blocking

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Overview

tcp_socket_server_v4.py:

• Handles full HTTP requests (including body)
• Can forward requests to external servers (proxy mode)
• Applies blocking rules and content filtering

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How It Works

General Flow

1. Parse arguments: config_path, --proxy, --ip, --port, --buffsize
2. Load JSON config (if provided):
   • blocked
   • forbidden_words
3. Start TCP server (bind, listen)
4. Accept client connections
5. Receive full HTTP request

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Modes

Simple Mode (default)

• Parses request
• Returns fixed HTTP 200 OK
• No external communication

Proxy Mode (--proxy)

1. Validate Host header
2. Checks request validity depending on .json criteria:
   • Block → 403 Forbidden
   • Invalid → 400 Bad Request
3. Forward request to destination server
4. Receive response (with timeout)
5. Send response (modified or not) back to client

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Usage

Simple Mode

python3 tcp_socket_server_v4.py --ip 127.0.0.1 --port 80

Proxy Mode

python3 tcp_socket_server_v4.py <config.json> --proxy --ip 127.0.0.1 --port 80

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Notes

• --buffsize defaults to 50
• --proxy requires a config file

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Config Example

{
  "blocked": ["example.com"],
  "forbidden_words": ["word1", "word2"]
}

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Key Design Choices

• Full HTTP request handling using Content-Length
• Modular functions (parsing, blocking, filtering)
• External JSON config (no hardcoding)
• Response rewriting with correct Content-Length
• Timeout for upstream server
• Clean socket handling