搜索多个索引并返回正确的类型

Question

我在 Elasticsearch 中设置了两个索引来存储不同类型的数据，我正在尝试同时从两个索引中使用嵌套获取搜索结果。我已经设置了如下模型...

public class Person
{
    [Number(Name="person_id")]
    public int Id { get; set; }
    [Date(Name = "person_created")]
    public DateTime Created { get; set; }
    ...
}

public class Work {
    [Number(Name="work_id")]
    public int Id { get; set; }
    [Date(Name = "work_created")]
    public DateTime Created { get; set; }
    ...
}

查询单个索引时，我可以执行以下操作并将结果映射回我的模型类型...

var request = new SearchRequest("works")
{
    From = searchQuery.Offset,
    Size = searchQuery.PageSize,
    Query = new QueryStringQuery { Query = searchQuery.SearchTerm },
 };

 var result = _elasticClient.Search<Work>(request);

但是，当执行如下查询时，如何告诉 Nest 将结果映射到每个索引的类型？

var request = new SearchRequest("works,person")
{
     ...
}
var result = _elasticClient.Search<object> ...

我看到的其他答案建议执行以下操作，但我认为 Types 函数已在 NEST 7.0 中删除...

client.Search<object>(s => s
    .Size(100)
    .SearchType(SearchType.Count)
    .Type(Types.Type(typeof(Dog), typeof(Cat)))

Answer 1

如果您可以控制文档索引，则可以利用 NEST 中的possibility to customize JSON serialization 进程，方法是将 .NET 类型放置在弹性搜索索引中的文档中。这样 NEST 会将文档反序列化为正确的类型。

class Program
{
    public class Person  
    {
        [Number(Name="person_id")]
        public int Id { get; set; }
        [Date(Name = "person_created")]
        public DateTime Created { get; set; }
    }

    public class Work 
    {
        [Number(Name="work_id")]
        public int Id { get; set; }
        [Date(Name = "work_created")]
        public DateTime Created { get; set; }
    }

    static void Main(string[] args)
    {
        var pool = new SingleNodeConnectionPool(new Uri("http://localhost:9200"));
        var connectionSettings =
            new ConnectionSettings(pool,
                sourceSerializer: (builtin, settings) => new JsonNetSerializer(builtin, settings,
                    () => new JsonSerializerSettings {TypeNameHandling = TypeNameHandling.All}
                ));
        var client = new ElasticClient(connectionSettings);

        var deleteIndexResponse = client.Indices.Delete("person,work");

        var createIndexResponse = client.Indices
            .Create("person", i => i.Map<Person>(m => m.AutoMap()));
        var createIndexResponse2 = client.Indices
            .Create("work", i => i.Map<Work>(m => m.AutoMap()));

        client.Index(new Person {Id = 1, Created = DateTime.UtcNow},
            i => i.Index("person"));
        client.Index(new Work {Id = 1, Created = DateTime.UtcNow},
            i => i.Index("work"));

        client.Indices.Refresh();

        var searchResponse = client.Search<object>(s => s
            .Index("person,work")
            .Query(q => q.MatchAll()));

        foreach (var document in searchResponse.Documents)
        {
            Console.WriteLine($"Person? {document is Person} Work? {document is Work}");
        }
    }
}

打印：

Person? True Work? False
Person? False Work? True

NEST.JsonNetSerializer 包需要安装在你的项目中。

希望对您有所帮助。