在platform: mqtt如何使用json格式发送命令

Kanson

我使用以下配控制风扇，可以正常获取设备状态信息，但使用开关命令控制设备时发送的MQTT消息payload部分为"OFF"或者"ON"，我期望是带json格式（例如：{"fan_state":"ON"}）。我尝试过把修改payload_on改为json格式，可以正常控制设备，但就解释不了设备状态了。如果在mqtt.swtich中可以单独设置payload_on和state_on,在mqtt.light中也可以另外设置command_on_template，但在mqtt.fan中只有payload_on设置。有解吗？谢谢！

fan:
  - platform: mqtt
    name: 'AirPuifier'
    state_topic: "zigbee2mqtt/0x00124b000434c1e0"
#    availability_topic: "zigbee2mqtt/bridge/state"
    state_value_template: "{{ value_json.fan_state }}"
    payload_off: "OFF"
    payload_on: "ON"
    command_topic: "zigbee2mqtt/0x00124b000434c1e0/set"
    speed_state_topic: "zigbee2mqtt/0x00124b000434c1e0"
    speed_command_topic: "zigbee2mqtt/0x00124b000434c1e0/set"
    speed_value_template: "{{ value_json.fan_mode }}"
    payload_off_speed: "off"
    payload_low_speed: "low"
    payload_medium_speed: "medium"
    payload_high_speed: "high"
    speeds: