Polymorphism? #17

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1. matt-lethargic commented on Jul 24, 2022

   

   matt-lethargic

   on Jul 24, 2022

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   Can you give me an example of what can't be done without this converter so I can understand the issue a little better?
2. SebastianStehle commented on Jul 24, 2022

   

   SebastianStehle

   on Jul 24, 2022

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   Lets say, I have the following request definition:

   class CreateGeometry
   {
    [Required]
    public GeoJsonObject Geometry {get; set; }
   }
   

   So the user can either give in a point or circle or polygon or whatever.

   I don't see how this is possible at the moment and I also tested it and got an error.
3. MartinCarpentier commented on Jul 30, 2022

   

   MartinCarpentier

   on Jul 30, 2022

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   What you want works by using the geometry interface.

   IGeometryObject
4. SebastianStehle commented on Jul 30, 2022

   

   SebastianStehle

   on Jul 30, 2022

   Last edited by SebastianStehle

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   Oh, sorry ... have not seen that. Why is there both a interface and a abstract class?
5. MartinCarpentier commented on Jul 30, 2022

   

   MartinCarpentier

   on Jul 30, 2022

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   I sadly do not know, since i have not been a part of the initial implementation of the library, i just converted it to system.text.json, but i guess the abstract class exists to share common properties to all of the geometry object types.
   Maybe it should be internal, since it makes no sense to use it externally.

   ❤️React with ❤️1Reacted by Sebastian Stehle
6. andreas-foreflight commented on Sep 9, 2022

   

   andreas-foreflight

   on Sep 9, 2022

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   Is there a way to get this to work with any GeoJson object, not only geometry types (i.e. also Feature and Feature Collection). Using IGeoJsonObject does not seem to work?

   I would like to serialize any type of geoJson object, but this does not work:

   >>> System.Text.Json.JsonSerializer.Serialize((GeoJSON.Text.IGeoJSONObject)source.Data)
   "{\"type\":8,\"crs\":null,\"bbox\":null}"
   

   I can properly serialize it as a feature collection, but this is not polymorphic:

   >>> System.Text.Json.JsonSerializer.Serialize((FeatureCollection)source.Data)
   "{\"type\":\"FeatureCollection\",\"features\":[{\"type\":\"Feature\",\"geometry\":{\"type\":\"LineString\",\"coordinates\":[[90,50],[25,0]]},\"properties\":{}}]}"
   

   Using IGeometryObject is not an option, because not all GeoJson objects are geometry objects:

   >>> System.Text.Json.JsonSerializer.Serialize((IGeometryObject)source.Data)
   'System.Text.Json.JsonSerializer.Serialize((IGeometryObject)source.Data)' threw an exception of type 'System.InvalidCastException'
       Data: {System.Collections.ListDictionaryInternal}
       HResult: -2147467262
       HelpLink: null
       InnerException: null
       Message: "Specified cast is not valid."
       Source: "006cbf0666ad4386b97cab13a906b566"
       StackTrace: "   at <>x.<>m0(<OnLoad>d__4 <>4__this)"
       TargetSite: {System.String <>m0(<OnLoad>d__4)}
   
7. hu-xd commented on Jul 19, 2023

   

   hu-xd

   on Jul 19, 2023

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   ditto. need to parse GeoJson data without knowing beforehand whether it is a geometry or feature or feature collection etc. how ?
8. crozone commented on Oct 16, 2023

   

   crozone

   on Oct 16, 2023

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   It looks like this is within reach, it just requires another converter for the top level IGeoJSONObject which can switch internally on GeoJSONObjectType, similar to how the polymorphic IGeometryObject converter works:

   GeoJSON.Text/src/GeoJSON.Text/Converters/GeometryConverter.cs

   Lines 86 to 107 in 31ec322

   	switch (geoJsonType)
   	{
   	case GeoJSONObjectType.Point:
   	return value.Deserialize<Point>(options);
   	case GeoJSONObjectType.MultiPoint:
   	return value.Deserialize<MultiPoint>(options);
   	case GeoJSONObjectType.LineString:
   	return value.Deserialize<LineString>(options);
   	case GeoJSONObjectType.MultiLineString:
   	return value.Deserialize<MultiLineString>(options);
   	case GeoJSONObjectType.Polygon:
   	return value.Deserialize<Polygon>(options);
   	case GeoJSONObjectType.MultiPolygon:
   	return value.Deserialize<MultiPolygon>(options);
   	case GeoJSONObjectType.GeometryCollection:
   	return value.Deserialize<GeometryCollection>(options);
   	case GeoJSONObjectType.Feature:
   	case GeoJSONObjectType.FeatureCollection:
   	default:
   	throw new NotSupportedException("Feature and FeatureCollection types are Feature objects and not Geometry objects");
   	}