RegionInfo在ElasticSearch中的序列化

Question

从序列化的角度来看，RegionInfo对象似乎已经被遗忘了。CultureInfo工作得很好，可以在字符串之间进行序列化。当尝试提交一个RegionInfo对象时，我得到了无法反序列化的RegionInfo所有属性的混乱，因为没有任何构造函数可以将所有这些属性反转。我希望只将RegionInfo序列化和反序列化为字符串，比如CultureInfo，但无法完全弄清楚这一点。

我的尝试：

我创建了一个区域信息转换器

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;
    }
}

我把它塞进了ConnectionSettings里：

var connectionSettings = new ConnectionSettings(pool,
    (builtin, settings) => new JsonNetSerializer(
        builtin,
        settings,
        contractJsonConverters: new JsonConverter[] { new RegionInfoConverter() })
);

但是我得到了错误：object mapping for [region] tried to parse field [region] as object, but found a concrete value

这听起来像是我的序列化器的一部分是错误的，但我觉得我不太明白它是哪一部分。谢谢。

Answer 1

我认为这里的问题可能是Elasticsearch最初从要索引的文档中推断了RegionInfo的RegionInfo数据类型映射，现在正在为RegionInfo传递一个string值。您可能需要删除索引并再次创建，将RegionInfo属性映射为keyword数据类型。

下面是一个有用的例子

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;
    }
}

索引请求发送以下JSON

{
  "regionInfo": "AU"
}