Home Assistant模板传感器报错：'this'未定义，原因何在？

架构老林

2026-7-23

Home Assistant 可复用AQI计算模板问题及优化方案

问题背景

家中添置多台宜家Vindstyrka空气质量传感器后，需要在Home Assistant中实现可复用的AQI计算逻辑，核心需求是定义一个能传入单个变量的可复用函数。尝试用自引用+合并键的方式编写模板，但在模板编辑器中运行时返回错误：UndefinedError: 'this' is undefined，启动防护方案也不适用此场景。

原错误代码

# AQI Calculation from https://www.airnow.gov/sites/default/files/2020-05/aqi-technical-assistance-document-sept2018.pdf p14
- sensor:
  - name: "Nursery AQI"
    unique_id: "sensor.nursery_aqi"
    attributes:
      particulates: "{{ states('sensor.airlink_pm_2_5') | float }}"
    <<: &aqi_from_pm25
      unit_of_measurement: "aqi"
      icon: mdi:blur
      state: >
        {% set pm = this.attributes.particulates %}
        {% if pm <= 12.0 %}
          {% set low = 0.0 %}
          {% set high = 50.0 %}
          {% set lowpm = 0.0 %}
          {% set highpm = 12.0 %}
        {% elif pm <= 35.4 %}
          {% set low = 50.0 %}
          {% set high = 100.0 %}
          {% set lowpm = 12.1 %}
          {% set highpm = 35.4 %}
        {% elif pm <= 55.4 %}
          {% set low = 101.0 %}
          {% set high = 150.0 %}
          {% set lowpm = 35.5 %}
          {% set highpm = 55.4 %}
        {% elif pm <= 150.4 %}
          {% set low = 151.0 %}
          {% set high = 200.0 %}
          {% set lowpm = 55.5 %}
          {% set highpm = 150.4 %}
        {% elif pm <= 250.4 %}
          {% set low = 201.0 %}
          {% set high = 300.0 %}
          {% set lowpm = 150.5 %}
          {% set highpm = 250.4 %}
        {% elif pm <= 350.4  %}
          {% set low = 301.0 %}
          {% set high = 400.0 %}
          {% set lowpm = 250.5 %}
          {% set highpm = 350.4 %}
        {% elif pm <= 500.4 %}
          {% set low = 401.0 %}
          {% set high = 500.0 %}
          {% set lowpm = 350.5 %}
          {% set highpm = 500.4 %}
        {% else %}
          {% set low = 501.0 %}
          {% set high = 502.0 %}
          {% set lowpm = 500.5 %}
          {% set highpm = 15000.0 %}
        {% endif %}
        {% set i_diff = high-low %}
        {% set pm_diff = highpm-lowpm %}
        {% set conc = pm-lowpm %}
        {{ ((conc * ((i_diff) / pm_diff)) + low) | round(0) }}
  - name: "Family Room AQI"
    unique_id: "sensor.family_room_aqi"
    <<: *aqi_from_pm25
    attributes:
      particulates: "{{ states('sensor.ikea_of_sweden_vindstyrka_particulate_matter_2') | float }}"
  - name: "Living Room AQI"
    unique_id: "sensor.living_room_aqi"
    <<: *aqi_from_pm25
    attributes:
      particulates: "{{ states('sensor.ikea_of_sweden_vindstyrka_particulate_matter') | float }}"
  - name: "TEST Outdoor AQI"
    unique_id: "sensor.test_outdoor_aqi"
    <<: *aqi_from_pm25
    attributes:
      particulates: "{{ states('sensor.airnow_pm2_5') | float }}"

问题原因

this变量仅在传感器实体运行时生效，模板编辑器调试阶段实体尚未创建，因此会报this未定义错误。此外，通过属性传递PM2.5值的方式不够直观，不利于调试。

优化方案：使用模板宏（Template Macro）

更优的实现方式是定义一个可接收PM2.5数值参数的宏，直接在每个传感器中调用宏完成计算，既解决调试问题，又提升代码复用性和可读性。

优化后的代码

# AQI Calculation 基于AirNow官方标准
- sensor:
  # 定义AQI计算宏
  - name: "AQI Calculation Macro"
    unique_id: "aqi_calculation_macro"
    state: >
      {% macro calculate_aqi(pm_value) %}
        {% if pm_value <= 12.0 %}
          {% set low = 0.0 %}{% set high = 50.0 %}{% set lowpm = 0.0 %}{% set highpm = 12.0 %}
        {% elif pm_value <= 35.4 %}
          {% set low = 50.0 %}{% set high = 100.0 %}{% set lowpm = 12.1 %}{% set highpm = 35.4 %}
        {% elif pm_value <= 55.4 %}
          {% set low = 101.0 %}{% set high = 150.0 %}{% set lowpm = 35.5 %}{% set highpm = 55.4 %}
        {% elif pm_value <= 150.4 %}
          {% set low = 151.0 %}{% set high = 200.0 %}{% set lowpm = 55.5 %}{% set highpm = 150.4 %}
        {% elif pm_value <= 250.4 %}
          {% set low = 201.0 %}{% set high = 300.0 %}{% set lowpm = 150.5 %}{% set highpm = 250.4 %}
        {% elif pm_value <= 350.4  %}
          {% set low = 301.0 %}{% set high = 400.0 %}{% set lowpm = 250.5 %}{% set highpm = 350.4 %}
        {% elif pm_value <= 500.4 %}
          {% set low = 401.0 %}{% set high = 500.0 %}{% set lowpm = 350.5 %}{% set highpm = 500.4 %}
        {% else %}
          {% set low = 501.0 %}{% set high = 502.0 %}{% set lowpm = 500.5 %}{% set highpm = 15000.0 %}
        {% endif %}
        {% set i_diff = high - low %}
        {% set pm_diff = highpm - lowpm %}
        {% set conc = pm_value - lowpm %}
        {{ ((conc * (i_diff / pm_diff)) + low) | round(0) if pm_diff != 0 else 0 }}
      {% endmacro %}
    # 宏实体无需实际状态，设置为隐藏
    entity_category: diagnostic
    hidden: true

  # 各房间AQI传感器
  - name: "Nursery AQI"
    unique_id: "sensor.nursery_aqi"
    unit_of_measurement: "aqi"
    icon: mdi:blur
    state: >
      {% from 'sensor.aqi_calculation_macro' import calculate_aqi %}
      {{ calculate_aqi(states('sensor.airlink_pm_2_5') | float) }}

  - name: "Family Room AQI"
    unique_id: "sensor.family_room_aqi"
    unit_of_measurement: "aqi"
    icon: mdi:blur
    state: >
      {% from 'sensor.aqi_calculation_macro' import calculate_aqi %}
      {{ calculate_aqi(states('sensor.ikea_of_sweden_vindstyrka_particulate_matter_2') | float) }}

  - name: "Living Room AQI"
    unique_id: "sensor.living_room_aqi"
    unit_of_measurement: "aqi"
    icon: mdi:blur
    state: >
      {% from 'sensor.aqi_calculation_macro' import calculate_aqi %}
      {{ calculate_aqi(states('sensor.ikea_of_sweden_vindstyrka_particulate_matter') | float) }}

  - name: "TEST Outdoor AQI"
    unique_id: "sensor.test_outdoor_aqi"
    unit_of_measurement: "aqi"
    icon: mdi:blur
    state: >
      {% from 'sensor.aqi_calculation_macro' import calculate_aqi %}
      {{ calculate_aqi(states('sensor.airnow_pm2_5') | float) }}

方案优势

调试友好：宏定义可单独在模板编辑器中测试，直接传入数值验证计算逻辑
复用性强：每个传感器只需一行代码调用宏，无需重复编写计算逻辑
逻辑清晰：PM2.5数据源直接传入宏参数，避免通过属性传递的间接性
容错处理：添加pm_diff != 0判断，避免除以零的错误

替代方案：使用YAML锚点+变量传递

如果不想使用宏，可通过调整锚点结构，直接在每个传感器中传递PM2.5变量，避免使用this：

# AQI Calculation 基于AirNow官方标准
- sensor:
  - name: "Nursery AQI"
    unique_id: "sensor.nursery_aqi"
    unit_of_measurement: "aqi"
    icon: mdi:blur
    <<: &aqi_sensor
      state: >
        {% set pm = pm_value %}
        {% if pm <= 12.0 %}
          {% set low = 0.0 %}{% set high = 50.0 %}{% set lowpm = 0.0 %}{% set highpm = 12.0 %}
        {% elif pm <= 35.4 %}
          {% set low = 50.0 %}{% set high = 100.0 %}{% set lowpm = 12.1 %}{% set highpm = 35.4 %}
        {% elif pm <= 55.4 %}
          {% set low = 101.0 %}{% set high = 150.0 %}{% set lowpm = 35.5 %}{% set highpm = 55.4 %}
        {% elif pm <= 150.4 %}
          {% set low = 151.0 %}{% set high = 200.0 %}{% set lowpm = 55.5 %}{% set highpm = 150.4 %}
        {% elif pm <= 250.4 %}
          {% set low = 201.0 %}{% set high = 300.0 %}{% set lowpm = 150.5 %}{% set highpm = 250.4 %}
        {% elif pm <= 350.4  %}
          {% set low = 301.0 %}{% set high = 400.0 %}{% set lowpm = 250.5 %}{% set highpm = 350.4 %}
        {% elif pm <= 500.4 %}
          {% set low = 401.0 %}{% set high = 500.0 %}{% set lowpm = 350.5 %}{% set highpm = 500.4 %}
        {% else %}
          {% set low = 501.0 %}{% set high = 502.0 %}{% set lowpm = 500.5 %}{% set highpm = 15000.0 %}
        {% endif %}
        {% set i_diff = high - low %}
        {% set pm_diff = highpm - lowpm %}
        {% set conc = pm - lowpm %}
        {{ ((conc * (i_diff / pm_diff)) + low) | round(0) if pm_diff != 0 else 0 }}
    variables:
      pm_value: "{{ states('sensor.airlink_pm_2_5') | float }}"

  - name: "Family Room AQI"
    unique_id: "sensor.family_room_aqi"
    <<: *aqi_sensor
    variables:
      pm_value: "{{ states('sensor.ikea_of_sweden_vindstyrka_particulate_matter_2') | float }}"

  - name: "Living Room AQI"
    unique_id: "sensor.living_room_aqi"
    <<: *aqi_sensor
    variables:
      pm_value: "{{ states('sensor.ikea_of_sweden_vindstyrka_particulate_matter') | float }}"

  - name: "TEST Outdoor AQI"
    unique_id: "sensor.test_outdoor_aqi"
    <<: *aqi_sensor
    variables:
      pm_value: "{{ states('sensor.airnow_pm2_5') | float }}"

此方案通过variables字段传递PM2.5数值，避免了this的使用，同样能实现代码复用，调试时可直接替换pm_value的数值测试逻辑。

内容的提问来源于stack exchange，提问作者USSJoin

Home Assistant模板传感器报错：'this'未定义，原因何在？

问题背景 #

原错误代码 #

问题原因 #

优化方案：使用模板宏（Template Macro） #

优化后的代码 #

方案优势 #

替代方案：使用YAML锚点+变量传递 #