C Robot Checker (Simple TCP Client)

A lightweight C program that demonstrates core network programming concepts by connecting to a local or remote web server, sending an HTTP GET request, and scanning the response for specific keywords (like "robot").

How it Works

The program follows the standard TCP Client Lifecycle:

1. Socket Creation: Initializes a socket using AF_INET (IPv4) and SOCK_STREAM (TCP).
2. Configuration: Sets up the destination IP (e.g., 127.0.0.1) and Port (e.g., 8000).
3. Connection: Performs a TCP three-way handshake with the server.
4. Request: Sends a raw HTTP GET request string.
5. Response: Captures the incoming data stream into a local buffer.
6. Analysis: Uses strstr() to scan the received HTML/text for the keyword "robot".

Getting Started

Prerequisites

• A C compiler (like gcc).
• Python 3 (for running a local test server).

Running the Project

1. Start a Local Server In one terminal, navigate to the folder containing your files and start a Python web server:

   python3 -m http.server 8000

2. Compile the C Code In a second terminal, compile the program:

   gcc functions.c -o functions

3. Execute Run the binary:

   ./functions

Debugging Features

The current version includes a Debug Block that prints the raw HTTP response headers and body. This is useful for verifying exactly what the server is sending before the logic scan occurs.

Learning Points

• Byte Ordering: Using htons() to ensure the port number is "Network Byte Order" compliant.
• Null Termination: Manually adding \0 to the end of the recv buffer so C string functions don't read into "garbage" memory.
• Blocking Calls: Understanding how recv() pauses program execution until data arrives from the server.

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Created as part of a deep dive into C Master networking logic.