led-controller/src/util/README.md

Driver message builder (espnow_message)

This utility builds v1 JSON payloads for LED drivers (serial/ESP-NOW bridge and Wi-Fi TCP). See docs/API.md for the full wire format.

Usage

Basic Message Building

from util.espnow_message import build_message, build_preset_dict, build_select_dict

# Build a message with presets and select
presets = {
    "red_blink": build_preset_dict({
        "pattern": "blink",
        "colors": ["#FF0000"],
        "delay": 200,
        "brightness": 255,
        "auto": True
    })
}

select = build_select_dict({
    "device1": "red_blink"
})

message = build_message(presets=presets, select=select)
# Result: {"v": "1", "presets": {...}, "select": {...}}

Building Select Messages with Step Synchronization

from util.espnow_message import build_message, build_select_dict

# Select with step for synchronization
select = build_select_dict(
    {"device1": "rainbow_preset", "device2": "rainbow_preset"},
    step_mapping={"device1": 10, "device2": 10}
)

message = build_message(select=select)
# Result: {"v": "1", "select": {"device1": ["rainbow_preset", 10], "device2": ["rainbow_preset", 10]}}

Converting Presets

from util.espnow_message import build_preset_dict, build_presets_dict

# Single preset
preset = build_preset_dict({
    "name": "my_preset",
    "pattern": "rainbow",
    "colors": ["#FF0000", "#00FF00"],  # Can be hex strings or RGB tuples
    "delay": 100,
    "brightness": 127,
    "auto": False,
    "n1": 2
})

# Multiple presets
presets_data = {
    "preset1": {"pattern": "on", "colors": ["#FF0000"]},
    "preset2": {"pattern": "blink", "colors": ["#00FF00"]}
}
presets = build_presets_dict(presets_data)

API Specification

See docs/API.md for REST routes, session scoping, and the compact preset keys on the wire.

Key Features

• Version Field: All messages include "v": "1" for version tracking
• Preset Format: Presets use hex colour strings (#RRGGBB), not RGB tuples
• Select Format: Select values are always lists: ["preset_name"] or ["preset_name", step]
• Colour Conversion: Automatically converts RGB tuples to hex strings
• Default Values: Provides sensible defaults for missing fields