Top Hits Aggregation Usage

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Fluent DSL example

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a => a
.Terms("states", t => t
    .Field(p => p.State)
    .Aggregations(aa => aa
        .TopHits("top_state_hits", th => th
            .Sort(srt => srt
                .Field(sf => sf
                    .Field(p => p.StartedOn)
                    .Order(SortOrder.Descending))
                .Script(ss => ss
                    .Type("number")
                    .Script(sss => sss
                        .Source("Math.sin(34*(double)doc['numberOfCommits'].value)")
                        .Lang("painless")
                    )
                    .Order(SortOrder.Descending)
                )
            )
            .Source(src => src
                .Includes(fs => fs
                    .Field(p => p.Name)
                    .Field(p => p.LastActivity)
                    .Field(p => p.SourceOnly)
                )
            )
            .Size(1)
            .Version()
            .TrackScores()
            .Explain()
            .StoredFields(f => f
                .Field(p => p.StartedOn)
            )
            .Highlight(h => h
                .Fields(
                    hf => hf.Field(p => p.Tags),
                    hf => hf.Field(p => p.Description)
                )
            )
            .ScriptFields(sfs => sfs
                .ScriptField("commit_factor", sf => sf
                    .Source("doc['numberOfCommits'].value * 2")
                )
            )
            .DocValueFields(d => d
                .Field(p => p.State)
            )
        )
    )
)

Object Initializer syntax example

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new TermsAggregation("states")
{
    Field = Field<Project>(p => p.State),
    Aggregations = new TopHitsAggregation("top_state_hits")
    {
        Sort = new List<ISort>
        {
            new FieldSort { Field = Field<Project>(p => p.StartedOn), Order = SortOrder.Descending },
            new ScriptSort
            {
                Type = "number",
                Script = new InlineScript("Math.sin(34*(double)doc['numberOfCommits'].value)") { Lang = "painless" },
                Order = SortOrder.Descending
            },
        },
        Source = new SourceFilter
        {
            Includes = new[] { "name", "lastActivity", "sourceOnly" }
        },
        Size = 1,
        Version = true,
        TrackScores = true,
        Explain = true,
        StoredFields = new[] { "startedOn" },
        Highlight = new Highlight
        {
            Fields = new Dictionary<Field, IHighlightField>
            {
                { Field<Project>(p => p.Tags), new HighlightField() },
                { Field<Project>(p => p.Description), new HighlightField() }
            }
        },
        ScriptFields = new ScriptFields
        {
            {
                "commit_factor", new ScriptField
                {
                    Script = new InlineScript("doc['numberOfCommits'].value * 2")
                }
            },
        },
        DocValueFields = Fields<Project>(f => f.State)
    }
}

Example json output.

{
  "states": {
    "terms": {
      "field": "state"
    },
    "aggs": {
      "top_state_hits": {
        "top_hits": {
          "sort": [
            {
              "startedOn": {
                "order": "desc"
              }
            },
            {
              "_script": {
                "type": "number",
                "script": {
                  "lang": "painless",
                  "source": "Math.sin(34*(double)doc['numberOfCommits'].value)"
                },
                "order": "desc"
              }
            }
          ],
          "_source": {
            "includes": [
              "name",
              "lastActivity",
              "sourceOnly"
            ]
          },
          "size": 1,
          "version": true,
          "track_scores": true,
          "explain": true,
          "stored_fields": [
            "startedOn"
          ],
          "highlight": {
            "fields": {
              "tags": {},
              "description": {}
            }
          },
          "script_fields": {
            "commit_factor": {
              "script": {
                "source": "doc['numberOfCommits'].value * 2"
              }
            }
          },
          "docvalue_fields": [
            "state"
          ]
        }
      }
    }
  }
}

Handling Responses

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response.ShouldBeValid();
var states = response.Aggregations.Terms("states");
states.Should().NotBeNull();
states.Buckets.Should().NotBeNullOrEmpty();
foreach (var state in states.Buckets)
{
    state.Key.Should().NotBeNullOrEmpty();
    state.DocCount.Should().BeGreaterThan(0);
    var topStateHits = state.TopHits("top_state_hits");
    topStateHits.Should().NotBeNull();
    topStateHits.Total.Value.Should().BeGreaterThan(0);
    var hits = topStateHits.Hits<Project>();
    hits.Should().NotBeNullOrEmpty();
    hits.All(h => h.Explanation != null).Should().BeTrue();
    hits.All(h => h.Version >= 0).Should().BeTrue();
    hits.All(h => h.Fields.ValuesOf<int>("commit_factor").Any()).Should().BeTrue();
    hits.All(h => h.Fields.ValuesOf<DateTime>("startedOn").Any()).Should().BeTrue();
    var projects = topStateHits.Documents<Project>();
    projects.Should().NotBeEmpty();
    projects.Should().OnlyContain(p => !string.IsNullOrWhiteSpace(p.Name), "source filter included name");
    projects.Should().OnlyContain(p => string.IsNullOrWhiteSpace(p.Description), "source filter does NOT include description");
    foreach (var project in projects)
        project.ShouldAdhereToSourceSerializerWhenSet();
}