yii\base\InvalidArgumentException: Malformed UTF-8 characters, possibly incorrectly encoded in C:\wwwroot\object\src\vendor\yiisoft\yii2\helpers\BaseJson.php:147

1、查看接口中的响应数据，定位原因在于响应字段中的 checkin_location_coordinates 为 MySQL 的 point 类型。如图1

图1

2、决定调整查询 SQL，使用 MySQL 的空间函数（如 ST_X 和 ST_Y）提取经纬度，避免直接操作 POINT 字段。通过 addSelect() 方法，可以在查询所有字段的基础上，额外添加经度和纬度字段。然后再 unset 掉 checkin_location_coordinates 字段。

SELECT * FROM `survey_forms` WHERE (`id`='1825203750690273') AND (`user_id`='1825203750689422') LIMIT 1

SELECT *, ST_X(checkin_location_coordinates) AS `checkin_location_longitude`, ST_Y(checkin_location_coordinates) AS `checkin_location_latitude` FROM `survey_forms` WHERE `id`='1825203750690273' LIMIT 1

$form = SurveyForm::find()
	->select('*') // 查询所有字段
	->addSelect([
		'ST_X(checkin_location_coordinates) AS checkin_location_longitude',
		'ST_Y(checkin_location_coordinates) AS checkin_location_latitude',
	])
	->where([
	'id' => $id,
])->limit(1)->asArray()->one();
unset($form['checkin_location_coordinates']);

3、但是，这种方案在所有的这个模型的查询中皆要调整。工作量超出预期。需要在模型文件中实现 自动添加查询 checkin_location_longitude、checkin_location_latitude。然后 unset(checkin_location_coordinates)。发现 未执行到 fields() 方法。最后仍然只有在控制器中 unset($form[‘checkin_location_coordinates’]);。决定仍然采用第二步骤的方案。

    public $checkin_location_longitude;
    public $checkin_location_latitude;

    public function afterFind()
    {
        parent::afterFind();
        // 设置经度和纬度
        $this->checkin_location_longitude = Yii::$app->db->createCommand("SELECT ST_X(checkin_location_coordinates) FROM {$this->tableName()} WHERE id = :id", [':id' => $this->id])->queryScalar();

        $this->checkin_location_latitude = Yii::$app->db->createCommand("SELECT ST_Y(checkin_location_coordinates) FROM {$this->tableName()} WHERE id = :id", [':id' => $this->id])->queryScalar();

        // 排除原始字段
        unset($this->checkin_location_coordinates);
    }

    public function fields()
    {
        $fields = parent::fields();
        Yii::debug('Fields before modification: ' . print_r($fields, true));
        // 添加自定义字段
        $fields['checkin_location_longitude'] = 'checkin_location_longitude';
        $fields['checkin_location_latitude'] = 'checkin_location_latitude';
        // 排除原始字段
        unset($fields['checkin_location_coordinates']);
        Yii::debug('Fields after modification: ' . print_r($fields, true));
        return $fields;
    }

$form = SurveyForm::find()->where([
            'id' => $id,
        ])->with(['fields', 'fields.diagram_image', 'fields.options', 'cover_image', 'submit_success_image'])->limit(1)->asArray()->one();

unset($form['checkin_location_coordinates']);

4、最终决定放弃使用 point 字段类型。调整为 checkin_location_longitude decimal(9,6) 、checkin_location_latitude decimal(9,6)