Switch off rules in GeoServer styles based on query parameters

switch-on-env.sld.xml

<?xml version="1.0" encoding="UTF-8"?>
<sld:UserStyle xmlns="http://www.opengis.net/sld"
xmlns:sld="http://www.opengis.net/sld" xmlns:ogc="http://www.opengis.net/ogc"
xmlns:gml="http://www.opengis.net/gml">
    <sld:Name>Default Styler</sld:Name>
    <sld:Title/>
    <sld:FeatureTypeStyle>
        <sld:Name>name</sld:Name>
        <sld:Rule>
            <ogc:Filter>
                <ogc:And>
                    <ogc:PropertyIsGreaterThan>
                        <ogc:Function name="env">
                            <ogc:Literal>var1</ogc:Literal>
                        </ogc:Function>
                        <ogc:Literal>1</ogc:Literal>
                    </ogc:PropertyIsGreaterThan>
                    <ogc:PropertyIsGreaterThan>
                        <ogc:Function name="env">
                            <ogc:Literal>var2</ogc:Literal>
                        </ogc:Function>
                        <ogc:Literal>2</ogc:Literal>
                    </ogc:PropertyIsGreaterThan>
                </ogc:And>
            </ogc:Filter>
            <sld:PolygonSymbolizer>
                <sld:Fill>
                    <sld:CssParameter name="fill">#ff0000</sld:CssParameter>
                </sld:Fill>
            </sld:PolygonSymbolizer>
        </sld:Rule>
    </sld:FeatureTypeStyle>
</sld:UserStyle>