How to catch remainder of JSON data that didn't match any POCO properties while using Elasticsearch Nest client and Utf8Json serializer

Question

I'm using the C# Elastic Nest client to retrieve the data from the Elasticsearch. I have created a POCO class named IndexModel which corresponds to the index mapping of my "testing-index" index. I get all the data from the index using this search method:

var result = client.Search<IndexModel>(s => s
                .Index("testing-index")
                .MatchAll());

However, I would like to be able to gather also the json data that didn't succeed to be mapped into any of the POCO properties, e.g. when the index mapping changes. I know that Nest uses Utf8Json as a Json serializer, but I couldn't find out if there is a possibility like in System.Text.Json.Serialization to add a data annotation above some dictionary that would catch all the overflow json data. Something like this?

[JsonExtensionData]
public Dictionary<string, object> ExtensionData { get; set; }

Or is there a possibility that the elastic client handles it and informs me somehow that some data didn't match any POCO properties?

Answer 1

There's no feature for this in the client.

The options are defining a POCO to represent the document, or using a type that can handle arbitrary JSON structures such as using JsonNetSerializer along with JObject to represent documents.