firmware-base/docs-c/core/CommandMessage.md

title	description	keywords
CommandMessage Class - Message Parsing System	Documentation for the CommandMessage class used to parse and structure messages in a Modbus system	ESP-32 Modbus communication command parsing messaging

CommandMessage

Path: src/modbus/command_message.h

Revision History: Initial documentation

The CommandMessage class provides a structured approach to parse, validate, and manage command messages within the system. It supports message serialization and deserialization with defined start/end markers and delimiters. This class is designed for efficient messaging in industrial Modbus-485 communications.

REQUIREMENTS

• No specific hardware pins required
• Requires StringUtils and enums support

PROVIDES

• CommandMessage: The main class for message handling
• DEBUG_MESSAGES_PARSE: Conditional compilation flag for verbose message parsing output
• DEBUG_MESSAGES_PARSER: Macro for debug logging of message parsing operations
• MESSAGE_TOKENS: Constant defining the expected number of tokens in a valid message

FEATURES

• Structured message storage with ID, verb, flags, and payload
• Timestamp tracking for message receipt
• Validation of message format with start/end markers
• Parsing of delimited message content
• Clear method for resetting message state
• Match checking for message format validation

DEPENDENCIES

• Vector
• ArduinoLog
• StringUtils
• Enums

graph TD
    CommandMessage --> StringUtils
    CommandMessage --> ArduinoLog
    CommandMessage --> Vector
    CommandMessage --> Enums

BEHAVIOUR

sequenceDiagram
    participant Client
    participant CommandMessage
    
    Client->>CommandMessage: Create message with id, verb, flags
    Client->>CommandMessage: parse(message)
    CommandMessage->>CommandMessage: clear()
    CommandMessage->>CommandMessage: Extract content between markers
    CommandMessage->>CommandMessage: Split by delimiters
    CommandMessage->>CommandMessage: Validate token count
    CommandMessage->>CommandMessage: Assign id, verb, flags, payload
    CommandMessage->>CommandMessage: Set timestamp
    CommandMessage-->>Client: Return success/failure

TODOS

PERFORMANCE

• Consider pre-allocating memory for the message parsing to avoid heap fragmentation
• Evaluate the use of String vs. char arrays for payload handling in memory-constrained environments
• Potential for optimizing token parsing with a more efficient approach than strtok

SECURITY

• Consider implementing message integrity checking (checksums or CRC)
• Add length validation to prevent buffer overflows
• Implement validation of message payload content based on expected verb/command

COMPLIANCE

• Ensure all message processing complies with Modbus protocol standards where applicable
• Consider adding support for standard industrial message formats

RECOMMENDATIONS

• Add support for binary payloads for more efficient communication
• Consider implementing a message queue system to handle multiple messages
• Add methods to serialize a CommandMessage back to a string for bidirectional communication
• Consider adding timeout functionality for message handling