Web Socket Console

WebSocket Console

A NetBurner NNDK application that provides WebSocket-based access to UART/serial ports and stdio console functionality.

Overview

This application creates WebSocket endpoints that allow web-based clients to communicate with:

• Standard I/O (stdin/stdout/stderr) via WebSocket
• Up to 10 UART/serial ports with configurable parameters

The application acts as a bridge between WebSocket connections and serial communication interfaces, enabling remote serial console access through a web browser.

Features

• WebSocket Console Access: Connect to the device's standard I/O streams via WebSocket
• UART Bridging: Access up to 10 UART ports through individual WebSocket connections
• Configurable Serial Parameters: Set baud rate, data bits, parity, and stop bits per UART
• Real-time Data Transfer: Bidirectional data flow between WebSocket and serial interfaces
• Connection Management: Automatic cleanup on connection errors
• Status Monitoring: Built-in diagnostics and connection status reporting

WebSocket Endpoints

Standard I/O Console

• Endpoint: stdio*
• Function: Redirects stdin, stdout, and stderr to the WebSocket connection
• Usage: General console access and debugging

UART Access

• Endpoint: uart*
• Function: Provides WebSocket access to individual UART ports
• Parameters (via query string):
  • uart: UART port number (0-9)
  • baud: Baud rate (1-230400)
  • data_bits: Data bits (5-8)
  • parity: Parity mode (0-2)
  • stop_bits: Stop bits (1-3)

Configuration Parameters

UART Configuration

• Port Range: 0-9 (10 total ports supported)
• Baud Rate Range: 1 to 230,400 bps
• Data Bits: 5, 6, 7, or 8 bits
• Parity: 0 (None), 1 (Odd), 2 (Even)
• Stop Bits: 1, 2, or 3 bits

System Settings

• Buffer Management: Automatic buffer allocation and cleanup
• Connection Limit: One WebSocket connection per UART port
• Error Handling: Automatic connection cleanup on errors

Usage Examples

Connecting to Standard I/O

ws://device-ip/stdio

Connecting to UART Port

ws://device-ip/uart?uart=0&baud=115200&data_bits=8&parity=0&stop_bits=1

This example connects to UART port 0 with:

• 115,200 bps baud rate
• 8 data bits
• No parity
• 1 stop bit

Application Architecture

Main Components

1. WebSocket Handlers: Process incoming WebSocket connections
2. UART Management: Handle serial port configuration and I/O
3. Data Bridging: Transfer data between WebSocket and serial interfaces
4. Connection Monitoring: Track active connections and handle errors

Key Functions

• StdioWS(): Handles stdio WebSocket connections
• UartWS(): Processes UART WebSocket requests
• spliceToWS(): Transfers data from UART to WebSocket
• spliceToUart(): Transfers data from WebSocket to UART
• ParseUartConfig(): Validates and parses UART configuration parameters

Error Handling

The application includes robust error handling for:

• Invalid UART configuration parameters
• Port availability conflicts
• WebSocket connection errors
• Serial port communication failures
• Buffer overflow conditions

HTTP Responses

• 400 Bad Request: Invalid configuration parameters
• 404 Not Found: Invalid WebSocket upgrade request
• 503 Not Available: Port already in use or unavailable

System Requirements

• NetBurner NNDK (NetBurner Real-Time Operating System)
• Network connectivity (Ethernet with DHCP)
• HTTP server support
• WebSocket protocol support
• Available UART hardware ports

Compilation Dependencies

• init.h - System initialization
• nbrtos.h - NetBurner RTOS functions
• websockets.h - WebSocket protocol support
• iosys.h - I/O system functions
• serial.h - Serial port management
• dhcpd.h - DHCP server functionality

Status Monitoring

The application provides real-time status information including:

• Active WebSocket connections
• UART port assignments
• Buffer usage statistics
• Connection health monitoring

Status updates are printed to the console every 10 seconds, showing:

• Current socket file descriptors
• UART port mappings
• Memory buffer availability

Troubleshooting

Common Issues

1. Port Already in Use: Ensure UART port is not already connected
2. Invalid Parameters: Check baud rate and bit configuration ranges
   
3. Connection Dropped: Monitor network stability and WebSocket client implementation
4. Buffer Overflow: Monitor system buffer usage in high-throughput scenarios

Diagnostic Features

• Built-in task stack checking (when NBRTOS_STACKCHECK is enabled)
• Connection status reporting
• Buffer usage monitoring
• Automatic error detection and cleanup