Resolve dynamic symbolizers from GeoServer

[KaiVolland]

The GeoServer allows a certain syntax to provide Symbolizers with dyanmic graphics derived from an attribute:
https://docs.geoserver.org/latest/en/user/styling/sld/extensions/pointsymbols.html#dynamic-symbolizers

The current code of the get method does not seem to work:
https://github.com/geostyler/geostyler-sld-parser/blob/main/src/Util/SldUtil.ts#L185

We have to check this code again.

Example style:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<StyledLayerDescriptor version="1.0.0" xsi:schemaLocation="http://www.opengis.net/sld StyledLayerDescriptor.xsd" xmlns="http://www.opengis.net/sld" xmlns:ogc="http://www.opengis.net/ogc" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:se="http://www.opengis.net/se">
  <NamedLayer>
    <Name>GeoStyler Demo</Name>
    <UserStyle>
      <Name>GeoStyler Demo</Name>
      <Title>GeoStyler Demo</Title>
      <FeatureTypeStyle>
        <Rule>
          <Name>Rule 1</Name>
          <PointSymbolizer>
            <Graphic>
              <ExternalGraphic>
                <OnlineResource xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="styleservlet/getIcon?name=${code}_selected.png"/>
              </ExternalGraphic>
              <Size>90</Size>
            </Graphic>
          </PointSymbolizer>
        </Rule>
      </FeatureTypeStyle>
    </UserStyle>
  </NamedLayer>
</StyledLayerDescriptor>

Describe the solution you'd like
I think it would make sense to use the same template syntax like we have in the TextSymbolizer.label.

Describe alternatives you've considered
As an alternative we could make use of the GeoStylerFunctions here and add somelike "asTemplateString" to the metadata.

Additional context
Add any other context or screenshots about the feature request here.

[jansule]

To me it looks like this is a geoserver specific solution and not part of the official SLD spec. So I think it should rather be part of the geostyler-geoserver-parser instead of the geostyler-sld-parser.

[KaiVolland]

I don't think there is a geostyler-geoserver-parser that is still maintained. We could think about supporting some GeoServer extras if it doesn't break the SLD parsing itself. I'm afraid maintaining another parser will be harder.