Whiteboard_Server

whiteboard server for collaborative drawing Collaborative Whiteboard (Windows)

Overview

This is a real-time collaborative whiteboard server designed to run on Windows.

• Serves an HTML page to any browser on the same machine or LAN.
• Users can draw in real-time using WebSockets.
• Includes simple colour selection and an eraser.

Files

• whiteboard_server_win_full.c – Windows server source code
• whiteboard_server_win_full.exe – Compiled Windows executable
• whiteboard.html – HTML client (embedded in the server; included for reference)

Requirements

• Windows (10/11 recommended)
• GCC (MinGW / MSYS2)
• OpenSSL installed (for WebSocket handshake: SHA1 + Base64)

Compilation

Open PowerShell or MSYS2 terminal:

gcc whiteboard_server_win_full.c -o whiteboard_server_win_full -lws2_32 -lssl -lcrypto

• -lws2_32 → Winsock2 (Windows networking)
• -lssl -lcrypto → OpenSSL (SHA1/Base64 for WebSocket handshake)

Running the Server

1. Open PowerShell and navigate to the folder containing the executable.
2. Run the server:

.\whiteboard_server_win_full.exe

3. The console will display:

Collaborative Whiteboard running at http://localhost:8080

Connecting from a Browser

On the same PC:

• Open a browser and navigate to: http://localhost:8080

On another device on the LAN (e.g., Mac):

1. Find the Windows machine’s IPv4 address:

ipconfig

• Look for IPv4 Address under the active network adapter (e.g., 192.168.1.42).

2. On the other device, open a browser and go to:

http://"your ip":8080

Note: Do not use localhost or 127.0.0.1 on another device — it will point to that device instead of the server.

Firewall Considerations

• Windows may block incoming connections.
• If prompted, allow access on Private networks.
• To allow manually:
  1. Open Windows Defender Firewall → Advanced settings.
  2. Create an Inbound Rule → TCP → Port 8080.
  3. Allow for Private networks.

Usage

• Open the whiteboard page on one or more devices.
• Draw using the mouse; colour can be changed using the buttons.
• Drawings are broadcast in real-time to all connected clients.

Notes

• This server is Windows-only.
• No external libraries are required for clients — just a modern web browser.
• WebSocket communication is unencrypted (HTTP only).
• The HTML page is embedded within the executable; no separate files are required for LAN usage.