RegionInfo serializing in ElasticSearch - elasticsearch

Question

It seems that the RegionInfo object has kinda been forgotten in terms of serialization. CultureInfo works great and is serialized to and from a string. When attempting to throw in a RegionInfo object, I get a mess of all the properties of RegionInfo that can't be deserialized because there is no constructor that takes all those properties in reverse. I would love to just serialize and deserialize the RegionInfos as strings, like CultureInfo, but can't quite figure that out.
My attempt:
I created a regioninfo converter
public class RegionInfoConverter : JsonConverter
{
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
serializer.Serialize(writer, ((RegionInfo)value).Name);
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
var token = JToken.Load(reader);
return new RegionInfo(token.ToObject<string>());
}
public override bool CanConvert(Type objectType)
{
return typeof(RegionInfo) == objectType;
}
}
I stuffed that into the ConnectionSettings:
var connectionSettings = new ConnectionSettings(pool,
(builtin, settings) => new JsonNetSerializer(
builtin,
settings,
contractJsonConverters: new JsonConverter[] { new RegionInfoConverter() })
);
but I get the error: object mapping for [region] tried to parse field [region] as object, but found a concrete value
That sounds like one of my serializer pieces is wrong, but I don't feel like I quite understand enough to figure out which part it is. Thanks.

Answer 1

I think the issue here may be that Elasticsearch has initially inferred an object datatype mapping for RegionInfo from a document to be indexed, and is now being passed a string value for RegionInfo. You may need to delete the index and create again, mapping the RegionInfo property as a keyword datatype.
Here's a working example
private static void Main()
{
var defaultIndex = "my_index";
var pool = new SingleNodeConnectionPool(new Uri("http://localhost:9200"));
var settings = new ConnectionSettings(pool, (b, s) =>
new JsonNetSerializer(b, s, contractJsonConverters: new JsonConverter[] { new RegionInfoConverter() })
)
.DefaultIndex(defaultIndex);
var client = new ElasticClient(settings);
if (client.IndexExists(defaultIndex).Exists)
client.DeleteIndex(defaultIndex);
var createIndexResponse = client.CreateIndex(defaultIndex, c => c
.Settings(s => s
.NumberOfShards(1)
.NumberOfReplicas(0)
)
.Mappings(m => m
.Map<MyEntity>(mm => mm
.AutoMap()
.Properties(p => p
.Keyword(k => k
.Name(n => n.RegionInfo)
)
)
)
)
);
var indexResponse = client.Index(new MyEntity
{
RegionInfo = RegionInfo.CurrentRegion
}, i => i.Refresh(Refresh.WaitFor));
}
public class MyEntity
{
public RegionInfo RegionInfo { get; set; }
}
public class RegionInfoConverter : JsonConverter
{
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
if (value == null)
{
writer.WriteNull();
return;
}
writer.WriteValue(((RegionInfo)value).Name);
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
if (reader.TokenType == JsonToken.Null)
return null;
if (reader.TokenType != JsonToken.String)
throw new JsonSerializationException($"Cannot deserialize {nameof(RegionInfo)} from {reader.TokenType}");
return new RegionInfo((string)reader.Value);
}
public override bool CanConvert(Type objectType)
{
return typeof(RegionInfo) == objectType;
}
}
The index request sends the following JSON
{
"regionInfo": "AU"
}