使用Nest Client在Elasticsearch中将嵌套属性复制到父对象 [英] Copying a nested property to parent object in elasticsearch with Nest client

问题描述

如何在索引映射定义中将嵌套属性复制到包含POCO的字段中?

How can I copy a nested property into a field of the containing POCO in an index mapping definition?

当两个字段处于同一对象级别时，我可以使用.CopyTo 成功地将一个属性复制到另一个属性中.

I am able to successfully copy a property into another property with .CopyTo when both fields are at the same object level.

但是我正在努力将嵌套对象的属性复制到父对象的属性.

However I am struggling with copying a property on a nested object into a property on the parent object.

鉴于以下对象，我想将街道"从人"的地址"属性复制到人"的搜索"属性

Given the objects below, I would like to copy 'Street' from the Address property on a Person into the 'Search' property on Person

Person
{
    public string Search { get; set; }
    public string LastName { get; set; }
    public Address Address { get; set; }
}

Address 
{
    public string Street { get; set; }
}

将姓氏"映射到搜索"很简单，如下所示.

Mapping 'LastName' into 'Search' is simple, as below.

.Map<Person>(map => map
                .AutoMap()
                .Properties(properties => properties
                .Text(text => 
                    text.Name(name => name.LastName)
                        .CopyTo(copyTo => 
                            copyTo.Field(field => field.Search)
                        )
                    )
                )

但是我无法弄清楚要复制的Nest语法 将"Person.Address.Street"转换为"Person.Search"

However I cannot figure out the Nest syntax to copy 'Person.Address.Street' into 'Person.Search'

推荐答案

这是您的操作方法

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

    var settings = new ConnectionSettings(pool)
        .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<Person>(mm => mm
                .AutoMap()
                .Properties(p => p
                    .Object<Address>(o => o
                        .Name(n => n.Address)
                        .AutoMap()
                        .Properties(pp => pp
                            .Text(t => t
                                .Name(nn => nn.Street)
                                .CopyTo(co => co
                                    .Field(Infer.Field<Person>(ff => ff.Search))
                                )
                            )
                        )
                    )
                )
            )
        )
    );

    var indexResponse = client.Index(new Person
        {
            LastName = "foo",
            Address = new Address
            {
                Street = "bar"
            }
        } , i => i
        .Refresh(Refresh.WaitFor)
    );

    var searchResponse = client.Search<Person>(s => s
        .Query(q => q
            .Match(m => m
                .Field(f => f.Search)
                .Query("bar")
            )
        )
    );
}

public class Person
{
    public string Search { get; set; }
    public string LastName { get; set; }
    public Address Address { get; set; }
}

public class Address
{
    public string Street { get; set; }
}

本质上

1. 自动映射Person属性
2. 明确映射Person上的Address属性
3. 自动映射Address属性
4. 明确映射Street属性并设置CopyTo(...).此时，泛型类型参数为Address类型，因此您需要使用Nest.Infer.Field<T>来访问Person的Search属性，或使用字符串.

1. Automap the Person properties
2. Explicitly map the Address property on Person
3. Automap the Address properties
4. Explicitly map the Street property and set up CopyTo(...). At this point, the generic type parameter is the Address type, so you either need to use Nest.Infer.Field<T> to access the Search property of Person, or use a string.

搜索返回预期的文档

{
  "took" : 2,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : 1,
    "max_score" : 0.2876821,
    "hits" : [
      {
        "_index" : "my_index",
        "_type" : "person",
        "_id" : "5tQDEWgBrKRHlz9qAve8",
        "_score" : 0.2876821,
        "_source" : {
          "lastName" : "foo",
          "address" : {
            "street" : "bar"
          }
        }
      }
    ]
  }
}

Elasticsearch中的

copy_to字段不一定需要作为C#POCO上的属性公开，因为_source不会包含它们的值.但是，作为属性公开可能对于强类型字段访问很有用.

copy_to fields in Elasticsearch don't necessarily need to be exposed as a property on the C# POCO, since the _source won't contain a value for them. Exposing as a property however may be useful for strong typing field access.

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