nest - 如何在 Elasticsearch.Net (NEST) 中将 POCO 与字段一起使用？

Question

在使用 Fields() 进行搜索时，如何获取强类型对象列表？例如:

var searchResult = client.Search<Person>(s => s
    .Fields("title", "name")
    .Query(q => q.Match(...etc...)
    .Highlight(...etc...)
);

使用 .Fields() 时，泛型类型参数似乎毫无用处，因为返回的 Hits 的 .Source 为空> 属性(property)。

(我希望有一种方法可以做到这一点，而无需手动将搜索结果映射回我原来的 Person POCO。)

Answer 1

当您在查询中使用 fields 参数时，elasticsearch 将返回响应的 fields 部分中的指定字段。

{
"took" : 36,
"timed_out" : false,
"_shards" : {
    "total" : 2,
    "successful" : 2,
    "failed" : 0
},
"hits" : {
    "total" : 18,
    "max_score" : 1.0,
    "hits" : [{
            "_index" : "nest_test_data-2672",
            "_type" : "elasticsearchprojects",
            "_id" : "1",
            "_score" : 1.0,
            "fields" : {
                "pingIP" : ["127.0.0.1"],
                "country" : ["Faroese"],
                "intValues" : [1464623485],
                "locScriptField" : [0],
                "stupidIntIWantAsLong" : [0],
                "floatValues" : [84.96025, 95.19422],
                "floatValue" : [31.93136],
                "myAttachment" : [""],
                "doubleValue" : [31.931359384176954],
                "suggest" : [""],
                "version" : [""],
                "content" : ["Bacon ipsum dolor sit amet tail non prosciutto shankle turducken, officia bresaola aute filet mignon pork belly do ex tenderloin. Ut laboris quis spare ribs est prosciutto, non short ribs voluptate fugiat. Adipisicing ex ad jowl short ribs corned beef. Commodo cillum aute, sint dolore ribeye ham hock bresaola id jowl ut. Velit mollit tenderloin non, biltong officia et venison irure chuck filet mignon. Meatloaf veniam sausage prosciutto qui cow. Spare ribs non bresaola, in venison sint short loin deserunt magna laborum pork loin cillum."],
                "longValue" : [-7046341211867792384],
                "myBinaryField" : [""],
                "name" : ["pyelasticsearch"],
                "boolValue" : [false],
                "id" : [1],
                "startedOn" : ["1994-02-28T12:24:26.9977119+01:00"]
            }
        }
    ]
}
}

您可以从 searchResult.FieldSelections 或 searchResult.Hits[...].Fields 检索它们。

就您而言Source filtering应该会方便很多。

        [Test]
    public void MatchAllShortcut()
    {
        var results = this.Client.Search<ElasticsearchProject>(s => s
            .From(0)
            .Size(10)
            .Source(source=>source.Include(f => f.Id, f => f.Country))
            .SortAscending(f => f.LOC)
            .SortDescending(f => f.Country)
            .MatchAll()
        );

        Assert.NotNull(results);
        Assert.True(results.IsValid);

        Assert.NotNull(results.Hits);
        Assert.GreaterOrEqual(results.Hits.Count(), 10);
        Assert.True(results.Hits.All(h => !string.IsNullOrEmpty(h.Source.Country)));

        Assert.NotNull(results.Documents);
        Assert.GreaterOrEqual(results.Documents.Count(), 10);
        Assert.True(results.Documents.All(d => !string.IsNullOrEmpty(d.Country)));
    }