ElasticSearch NEST - all fields are NULL

Elastic Stack Elasticsearch
1

I'm trying to retrieve data from elastic search with NEST. Everything would be good, but NEST all fields return null. However, in debug mode I see that it counts the documents correctly but not showing the value of fields.

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What I already did:

  • checked mapping and its seems fine to me.
  • tried String Querry.
  • tried to get source and then read data.
  • tried NEST returns null instead of fields those solution did not help either.
  • Renamed Product.cs field names to camelCase did not help either.
    Heres my code right now:
public class ElasticSearch
{
    private ElasticClient _client;

    public ElasticSearch()
    {
        var node = new Uri("http://localhost:9200");
        var settings = new ConnectionSettings(node);
        settings.DefaultIndex("logsystem.logs");
        _client = new ElasticClient(settings);
    }

    public void searchResults()
    {
        var searchResults = _client.Search<Product>(s => s.AllIndices());


    }
}

Product.cs

    [BsonIgnoreExtraElements]
    public class Product
    {
        [BsonId]
        [BsonIgnore]
        public ObjectId Id { get; set; }
        [Required]
        public string Name { get; set; }
        [Required]
        public string ProductLicenseKey { get; set; }
        [Required]
        public string Action { get; set; }
        [Required]
        public string ActionName { get; set; }
        [Required]
        public string MachineId { get; set; }
    }

Mapping in ElasticSearch:

{
"logsystem.logs": {
    "mappings": {
        "properties": {
            "Action": {
                "type": "text",
                "fields": {
                    "keyword": {
                        "type": "keyword",
                        "ignore_above": 256
                    }
                }
            },
            "ActionName": {
                "type": "text",
                "fields": {
                    "keyword": {
                        "type": "keyword",
                        "ignore_above": 256
                    }
                }
            },
            "MachineId": {
                "type": "text",
                "fields": {
                    "keyword": {
                        "type": "keyword",
                        "ignore_above": 256
                    }
                }
            },
            "Name": {
                "type": "text",
                "fields": {
                    "keyword": {
                        "type": "keyword",
                        "ignore_above": 256
                    }
                }
            },
            "ProductLicenseKey": {
                "type": "text",
                "fields": {
                    "keyword": {
                        "type": "keyword",
                        "ignore_above": 256
                    }
                }
            }
        }
    }
}
}

ElasticSearch Documents get via postman:

{
"took": 11,
"timed_out": false,
"_shards": {
    "total": 1,
    "successful": 1,
    "skipped": 0,
    "failed": 0
},
"hits": {
    "total": {
        "value": 6,
        "relation": "eq"
    },
    "max_score": 1.0,
    "hits": [
        {
            "_index": "logsystem.logs",
            "_type": "_doc",
            "_id": "5e5c1ca2aaa6f1245cc38895",
            "_score": 1.0,
            "_source": {
                "Action": "Button",
                "ActionName": "Fixed Single Generation",
                "MachineId": "987-654-321",
                "Name": "System",
                "ProductLicenseKey": "123-456-789"
            }
        },
        {
            "_index": "logsystem.logs",
            "_type": "_doc",
            "_id": "5e5c1cb0aaa6f1245cc38896",
            "_score": 1.0,
            "_source": {
                "Action": "Button",
                "ActionName": "Fixed Multiple Generation",
                "MachineId": "987-654-321",
                "Name": "System",
                "ProductLicenseKey": "123-456-789"
            }
        },
        {
            "_index": "logsystem.logs",
            "_type": "_doc",
            "_id": "5e5c1cbdaaa6f1245cc38897",
            "_score": 1.0,
            "_source": {
                "Action": "Button",
                "ActionName": "Trackers Single Generation",
                "MachineId": "987-654-321",
                "Name": "System",
                "ProductLicenseKey": "123-456-789"
            }
        },
        {
            "_index": "logsystem.logs",
            "_type": "_doc",
            "_id": "5e5c1ccbaaa6f1245cc38898",
            "_score": 1.0,
            "_source": {
                "Action": "Button",
                "ActionName": "Trackers Multiple Generation",
                "MachineId": "987-654-321",
                "Name": "System",
                "ProductLicenseKey": "123-456-789"
            }
        },
        {
            "_index": "logsystem.logs",
            "_type": "_doc",
            "_id": "5e5c1cd3aaa6f1245cc38899",
            "_score": 1.0,
            "_source": {
                "Action": "Button",
                "ActionName": "Fixed Multiple Generation",
                "MachineId": "987-654-321",
                "Name": "System",
                "ProductLicenseKey": "123-456-789"
            }
        },
        {
            "_index": "logsystem.logs",
            "_type": "_doc",
            "_id": "5e5c1ce0aaa6f1245cc3889a",
            "_score": 1.0,
            "_source": {
                "Action": "Button",
                "ActionName": "Tree Generation",
                "MachineId": "987-654-321",
                "Name": "System",
                "ProductLicenseKey": "123-456-789"
            }
        }
    ]
 }
}

Maybe my mapping is not right? any answer would help. Thanks.
By the way, data to elasticSearch was inserted using monstache from mongo database.

2

I suspect the issue is that by default, the client expects to deserialize camel-cased JSON object keys to the POCO properties, and is strict about casing.

You can override this default using DefaultFieldNameInferrer on ConnectionSettings. Since the mapping contains Pascal cased field names that look like they map directly to the POCO property names, the following should work

var node = new Uri("http://localhost:9200");
var settings = new ConnectionSettings(node)
	.DefaultIndex("logsystem.logs")
	.DefaultFieldNameInferrer(p => p);

var client = new ElasticClient(settings);
1 Like
3

Thank you, that helped!

4

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