c4wled.sh/wled

#!/bin/sh
#
# Simpel command line tool to turn predefined wled instances on/off or switch
# presets.
#
# Author: Shy
# License: CC0

print_usage() {
    echo "Usage: $0 f(nordcenter)|w(ohnzimmer) on|off|1-17|list"
    echo "       $0 f(nordcenter)|w(ohnzimmer) b(rightness) 1-255"
}

curl_cmd() {
    curl --silent --show-error --fail --ipv4 --max-filesize 32K "$@"
}

# Parse host argument.
case "$1" in
    ""|-h|--h) # Missing host parameter.
        print_usage
        exit 0
    ;;
    f|fnordcenter)
        wled_host='wled-fnordcenter.local'
    ;;
    w|wohnzimmer)
        wled_host='wled-wohnzimmer.local'
    ;;
    *) # Unknown host parameter.
        echo "Error: unknown host \"$1\"." >&2
        print_usage
        exit 1
    ;;
esac

# Parse and execute command argument.
case "$2" in
    on) # Switch on.
        api_resp=$(curl_cmd --json '{"on":true}' "http://$wled_host/json")
    ;;
    off) # Switch off.
        api_resp=$(curl_cmd --json '{"on":false}' "http://$wled_host/json")
    ;;
    b|brightness) # Set brightness.
        if test -z "$3"; then
            echo "Error: missing parameter for brightness." >&2
            exit 1
        fi
        # Try to convert 3rd parameter to an integer between 1 an 255.
        bright=$(printf '%u' "$3" 2>/dev/null)
        if test $? -gt 0; then # Conversion failed.
            echo "Error: unable to parse parameter for brightness." >&2
            exit 1
        elif test "$bright" -lt 1 -o "$bright" -gt 255; then
            echo "Error: parameter for brightness is out of range." >&2
            exit 1
        fi
        api_resp=$(curl_cmd --json "{'bri':$bright}" "http://$wled_host/json")
    ;;
    [1-9]|1[0-7]) # Switch to preset.
        api_resp=$(curl_cmd --json "{'ps':$2}" "http://$wled_host/json")
    ;;
    l|list) # List presets.
        echo "Presets on $wled_host:"
        curl_cmd "http://$wled_host/presets.json" | \
            # Split into lines - one line per preset. Append final newline.
            sed --sandbox 's/"\(1\?[0-9]\)"/\n"\1"/g; $a\ ' | \
            # Extract number and name of every preset.
            sed --sandbox -n 's/^"\(1\?[0-9]\)":.*"n":"\([[:print:]]*\)".*$/\1: \2/p'
        exit $?
    ;;
    dump) # Dump JSON response from API.
        curl_cmd -w '\n' "http://$wled_host/json"
        exit 0
    ;;
    "") # Missing command.
        echo "Error: missing command." >&2
        print_usage
        exit 1
    ;;
    *) # Unknown command.
        echo "Error: unknown command \"$2\"." >&2
        print_usage
        exit 1
    ;;
esac

# Check curl exit status
curl_exit=$?
if test $curl_exit -ne 0; then
    echo "Error: curl exited with exit code $curl_exit." >&2
    exit 1
fi

# Check API responce.
if test "$api_resp" != '{"success":true}'; then
    echo "Error: unexpected responce from WLED API." >&2
    exit 1
fi