/// <summary>
/// Reads the json and converts to appropriate Geometry class using the 'type' field as an indicator
/// to which object it should be deserialized back to
/// </summary>
/// <param name="reader"></param>
/// <param name="objectType"></param>
/// <param name="existingValue"></param>
/// <param name="serializer"></param>
/// <returns></returns>
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
JObject Token = JObject.Load(reader);
if (!Token.TryGetValue("type", StringComparison.OrdinalIgnoreCase, out JToken TypeToken))
{
throw new JsonReaderException("Invalid geojson geometry object, does not have 'type' field.");
}
Type ActualType = Geometry.GetType(TypeToken.ToObject <GeoJsonType>(serializer));
if (existingValue == null || existingValue.GetType() != ActualType)
{
return(Token.ToObject(ActualType, serializer));
}
else
{
using (JsonReader DerivedTypeReader = Token.CreateReader())
{
serializer.Populate(DerivedTypeReader, existingValue);
}
return(existingValue);
}
}
/// <summary>
/// Reads the json and converts to appropriate GeoJson class using the 'type' field as an indicator
/// to which object it should be deserialized back to
/// </summary>
/// <param name="reader"></param>
/// <param name="objectType"></param>
/// <param name="existingValue"></param>
/// <param name="serializer"></param>
/// <returns></returns>
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
// Allow an abstract GeoJson to be null in deserialization
if (reader.TokenType == JsonToken.Null)
{
return(null);
}
JObject token = JObject.Load(reader);
if (!token.TryGetValue("type", StringComparison.OrdinalIgnoreCase, out JToken TypeToken))
{
throw new JsonReaderException("Invalid geojson object, does not have 'type' field.");
}
Type actualType = GeoJson.GetType(TypeToken.ToObject <GeoJsonType>(serializer));
if (existingValue == null || existingValue.GetType() != actualType)
{
return((GeoJson)token.ToObject(actualType, serializer));
}
else
{
using (JsonReader derivedTypeReader = token.CreateReader())
{
serializer.Populate(derivedTypeReader, existingValue);
}
return(existingValue);
}
}
public override GeoJSONObject ReadJson(JsonReader reader, Type objectType, GeoJSONObject existingValue, bool hasExistingValue, JsonSerializer serializer)
{
if (reader.TokenType == JsonToken.Null) //GeoJSONObject can be abstract
{
return(null);
}
JObject token = JObject.Load(reader);
if (!token.TryGetValue("type", StringComparison.OrdinalIgnoreCase, out JToken TypeToken))
{
throw new JsonReaderException("Invalid geojson object, does not have 'type' field.");
}
// Match GeoJSONType to actual type
GeoJSONType tokenType = TypeToken.ToObject <GeoJSONType>(serializer);
Type actualType = tokenType switch
{
GeoJSONType.Point => typeof(Point),
GeoJSONType.LineString => typeof(LineString),
GeoJSONType.Polygon => typeof(Polygon),
GeoJSONType.Feature => typeof(Feature),
GeoJSONType.FeatureCollection => typeof(FeatureCollection),
_ => null, //TODO: proper check here
};
if (existingValue == null || existingValue.GetType() != actualType)
{
return((GeoJSONObject)token.ToObject(actualType, serializer));
}
else
{
using (JsonReader derivedTypeReader = token.CreateReader())
{
serializer.Populate(derivedTypeReader, existingValue);
}
return(existingValue);
}
}
