7.0.0 - Cannot parse hits._source into ISearchResponse.Documents

NEST/Elasticsearch.Net version: 7.0.0-alpha1

Elasticsearch version: 7.0.0

Description of the problem including expected versus actual behavior:

Hi, I’ve sent search request via Nest IElasticClient.SearchAsync() as following:

GET /player_profile*/_search
{
  "query": {
    "bool": {
      "should": [
        {
          "match": {
            "LoginId": {
              "query": "loginId1"
            }
          }
        },
        {
          "match": {
            "MobileNumber": {
              "query": "loginId1"
            }
          }
        },
        {
          "match": {
            "Email": {
              "query": "loginId1"
            }
          }
        }
      ]
    }
  },
  "_source": {
    "includes": [
      "PlayerId"
    ]
  }
}

result

{
  "took" : 1,
  "timed_out" : false,
  "_shards" : {
    "total" : 5,
    "successful" : 5,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 1,
      "relation" : "eq"
    },
    "max_score" : 0.6931472,
    "hits" : [
      {
        "_index" : "player_profile",
        "_type" : "doc",
        "_id" : "663b433e-f36b-1410-8104-004df507d47e",
        "_score" : 0.6931472,
        "_source" : {
          "PlayerId" : "663b433e-f36b-1410-8104-004df507d47e"
        }
      }
    ]
  }
}

POCO class in c#

public sealed class PlayerElkData
{
        public Guid PlayerId { get; set; }
        public string MobileNumber { get; set; }
        public string Email { get; set; }
        public string LoginId { get; set; }
}

The search result could be deserialized into ISearchResponse.Hits, however ISearchResponse.Documents and ISearchResponse.Hits[0].Source are both empty objects

It should deserialize “663b433e-f36b-1410-8104-004df507d47e” into PlayerId property

Is there something wrong in request, response or the POCO class?

Any suggestion would be appreciated, thank you!

Provide DebugInformation (if relevant):

(some part of ip address were masked)

Valid NEST response built from a successful low level call on POST: /player_profile/_search?typed_keys=true Audit trail of this API call:

• [1] SniffOnStartup: Took: 00:00:00.2516981
• [2] SniffSuccess: Node: http://172.16..:9200/ Took: 00:00:00.2463194
• [3] PingSuccess: Node: http://172.16..:9200/ Took: 00:00:00.0203828
• [4] HealthyResponse: Node: http://172.16..:9200/ Took: 00:00:00.0987998 Request: <Request stream not captured or already read to completion by serializer. Set DisableDirectStreaming() on ConnectionSettings to force it to be set on the response.> Response: <Response stream not captured or already read to completion by serializer. Set DisableDirectStreaming() on ConnectionSettings to force it to be set on the response.>

[russcam]

the serializer in NEST 7.0 is stricter with regards to JSON field -> POCO property name casing. Where 6.x would be somewhat case insensitive during deserialization, 7.x is not.

The default casing is Camel casing in NEST, so the serializer looks for a playerId field in JSON to deserialize into the PlayerId property. If the DefaultFieldNameInferrer() is specified to use Pascal casing then deserialization works as expected

void Main()
{
	
	var pool = new SingleNodeConnectionPool(new Uri("http://localhost:9200"));

	var bytes = Encoding.UTF8.GetBytes(@"{
  ""took"" : 1,
  ""timed_out"" : false,
  ""_shards"" : {
    ""total"" : 5,
    ""successful"" : 5,
    ""skipped"" : 0,
    ""failed"" : 0
  },
  ""hits"" : {
    ""total"" : {
      ""value"" : 1,
      ""relation"" : ""eq""
    },
    ""max_score"" : 0.6931472,
    ""hits"" : [
      {
        ""_index"" : ""player_profile"",
        ""_type"" : ""doc"",
        ""_id"" : ""663b433e-f36b-1410-8104-004df507d47e"",
        ""_score"" : 0.6931472,
        ""_source"" : {
          ""PlayerId"" : ""663b433e-f36b-1410-8104-004df507d47e""
        }
      }
    ]
  }
}");

	var connection = new InMemoryConnection(bytes);
	
	var settings = new ConnectionSettings(pool, connection)
		.DefaultFieldNameInferrer(f => f);

	var client = new ElasticClient(settings);
	
	var searchResponse = client.Search<PlayerElkData>(s => s.Index("foo"));
	//  663b433e-f36b-1410-8104-004df507d47e as expected
	var id = searchResponse.Documents.First().PlayerId;
}

public sealed class PlayerElkData
{
	public Guid PlayerId { get; set; }
	public string MobileNumber { get; set; }
	public string Email { get; set; }
	public string LoginId { get; set; }
}

@Mpdreamz @codebrain being more lenient here for document POCOs would have a performance impact, as it would require encoding differently cased property names into an AutomataDictionary against which the POCO property name is matched.

[russcam]

Thanks @codebrain. This is something we should definitely call out 👍