Custom Range Limit Config Variables

Custom Range Limit Configuration Demo

A NetBurner embedded application demonstrating advanced configuration system capabilities with custom validation objects and range-limited configuration variables.

Overview

This application showcases the NetBurner Config system by implementing custom configuration object classes that extend the base config_obj functionality. The demo specifically focuses on creating configuration variables with custom validation logic, including a novel color brightness validator.

Key Features

Built-in Configuration Objects

The application demonstrates several built-in NetBurner configuration object types:

• config_string_limit - String with length constraints (1-10 characters)
• config_int_limit - Integer with range validation (-200 to 200)
• config_uint_limit - Unsigned integer with range validation (0 to 300)
• config_double_limit - Double with range and precision validation (-10.0 to 10.0, 0.01 step)
• config_pass_limit - Password field with length constraints (5-128 characters)

Custom Configuration Object: Color Brightness Validator

The centerpiece of this demo is the config_color_brightlimit class, which validates HTML color strings based on perceived brightness:

• Accepts hex color strings in format #rrggbb (e.g., #00ccff)
• Calculates perceived brightness using ITU-R Recommendation BT.601 coefficients
• Enforces minimum and maximum brightness thresholds
• Provides meaningful error messages for invalid inputs

Brightness Calculation

The luminance calculation uses the ITU standard coefficients:

Luminance = (0.2582 * R + 0.66 * G + 0.0818 * B) * 100 / 255

Configuration Variables

The application defines several global configuration variables:

Variable	Type	Default	Range/Limit	Description
gSingleString	config_string_limit	"SNameLimit"	1-10 chars	String length demo
gMyOwnVal	config_int_limit	199	-200 to 200	Integer range demo
gMyOwnuVal	config_uint_limit	299	0 to 300	Unsigned int range demo
gMyOwndVal	config_double_limit	9.0	-10.0 to 10.0	Double precision demo
gMyOwnpVal	config_pass_limit	""	5-128 chars	Password field demo
gMyDarkColor	config_color_brightlimit	"#331122"	0-50% brightness	Dark color validator
gMyLightColor	config_color_brightlimit	"#cceeff"	50-100% brightness	Light color validator

Interactive Commands

The application provides a serial console interface with the following commands:

• C - Show Config Tree: Display the complete configuration hierarchy
• S - Show and Set gSingleString: Modify the string limit example
• V - Show and Set gMyOwnVal: Modify the integer limit example
• U - Show and Set gMyOwnuVal: Modify the unsigned integer limit example
• N - New/Create dynamic variable: Create a new config variable at runtime
• D - Delete dynamic variable: Remove the dynamically created variable
• Q - Query dynamic variable: Display the value of the dynamic variable
• ? - Show Command List: Display available commands

Technical Implementation

Custom Validation Logic

The config_color_brightlimit class demonstrates several advanced concepts:

1. Server-side Validation: The TestNewValue() method provides robust server-side validation with custom error messages
2. Client-side Schema: The ExtendedSchema() method adds HTML pattern validation for web-based configuration
3. Operator Overloading: Multiple assignment operators handle different input types while maintaining validation
4. Error Reporting: Uses LogParseError() to provide user-friendly error messages

Dynamic Configuration Management

The application shows how to:

• Create configuration objects dynamically at runtime
• Properly manage memory for dynamic config objects
• Use FixNonStaticObject() for runtime-created config variables

Web Interface Integration

The configuration system automatically generates a web-based configuration interface at the device's IP address. The custom validation rules are enforced both in the web UI (client-side) and on the device (server-side).

Network Information

Upon startup, the application displays:

• Device IP address
• AutoIP address
• Gateway address
• Configuration space usage statistics

Building and Running

This application is designed for NetBurner embedded systems. Ensure you have:

• NetBurner development environment installed
• Compatible NetBurner hardware platform
• Network connectivity for web-based configuration access

Configuration Storage

All configuration changes are automatically persisted to non-volatile storage using the NetBurner configuration system. Changes survive device reboots and power cycles.

Use Cases

This demo is particularly useful for:

• Learning NetBurner configuration system concepts
• Implementing custom validation logic for configuration parameters
• Creating domain-specific configuration objects
• Understanding client-server validation patterns
• Building robust embedded configuration systems

Error Handling

The application includes comprehensive error handling for:

• Invalid color format strings
• Out-of-range brightness values
• Network connectivity issues
• Memory management for dynamic objects

Extension Points

The framework demonstrated here can be extended to create custom validators for:

• IP address ranges
• Time/date validation
• File path validation
• Custom protocol parameters
• Hardware-specific constraints