Mapping with Elasticsearch

Question

When trying to read certain fields from ElasticSearch, I noticed that if I do not include a text attribute then it will not map the variable name to the field. It will read null for that specific field. Lets say I have a field in ES named ValueId of type text. In my model class I have public string ValueId {get; set;}. ValueId should have a value for that variable, but when I do not add a Elasticsearch Property Attribute i.e. [Text(Name = "ValueId")] it returns null.

Now if I have it as the following, then it will return a value for that variable.

[Text(Name = "ValueId")]
public string ValueId {get; set;}

My guess is because of the camel casing, is that correct?

On another note, is there a way I could set that property name (Name = "") dynamically? As in create a method to do this.

Answer 1

Work with NEST Automapping, it always helps me with these questions: https://www.elastic.co/guide/en/elasticsearch/client/net-api/current/auto-map.html

Another point is to correctly configure your elastic with NEST, the example below shows the correct way of configuration:

public static void AddElasticsearch(this IServiceCollection services, IConfiguration configuration, bool configureDefaultQuery = true)
{
    var defaultIndex = configuration["ElasticsearchSettings:defaultIndex"];
    var basicAuthUser = configuration["ElasticsearchSettings:username"];
    var basicAuthPassword = configuration["ElasticsearchSettings:password"];

    var settings = new ConnectionSettings(new Uri(configuration["ElasticsearchSettings:uri"]));

    if (!string.IsNullOrEmpty(defaultIndex))
        settings = settings.DefaultIndex(defaultIndex);

    if (!string.IsNullOrEmpty(basicAuthUser) && !string.IsNullOrEmpty(basicAuthPassword))
        settings = settings.BasicAuthentication(basicAuthUser, basicAuthPassword);

    var client = new ElasticClient(settings);

    services.AddSingleton<IElasticClient>(client);
}

Se mesmo assim continuar vindo nulo, experimente utiliar a configuração: settings.DefaultFieldNameInferrer(p => p);

More details can be found in this example project: https://github.com/hgmauri/elasticsearch-with-nest