NEST (ElasticSearch) search response drops aggregates - elasticsearch

Question

Here is a query that works in ElasticSearch.
"query":{
"match_all":{
}
},
"size":20,
"aggs":{
"CompanyName.raw":{
"terms":{
"field":"CompanyName.raw",
"size":20,
"order":{
"_count":"desc"
}
}
}
}
}
The response from ElasticSearch has a property aggregations['CompanyName.raw']['buckets'] which is an array.
I use this code to exeute the same query via NEST
string responseJson = null;
ISearchResponse<ProductPurchasing> r = Client.Search<ProductPurchasing>(rq);
using (MemoryStream ms = new MemoryStream())
{
Client.RequestResponseSerializer.Serialize<ISearchResponse<ProductPurchasing>>(r, ms);
ms.Position = 0;
using (StreamReader sr = new StreamReader(ms))
{
responseJson = sr.ReadToEnd();
}
}
However, in the resulting responseJson this array is always empty.
Where hs it gone?
How can I get it back?
Or is it that NEST doesn't support aggregates?

Answer 1

NEST does support aggregation, you can have a look into docs on how to handle aggregation response with NEST help.
Here you can find a short example of writing and retrieving data from simple terms aggregation:
class Program
{
public class Document
{
public int Id { get; set; }
public string Name { get; set; }
public string Brand { get; set; }
public string Category { get; set; }
public override string ToString() => $"Id: {Id} Name: {Name} Brand: {Brand} Category: {Category}";
}
static async Task Main(string[] args)
{
var pool = new SingleNodeConnectionPool(new Uri("http://localhost:9200"));
var connectionSettings = new ConnectionSettings(pool);
connectionSettings.DefaultIndex("documents");
var client = new ElasticClient(connectionSettings);
var deleteIndexResponse = await client.Indices.DeleteAsync("documents");
var createIndexResponse = await client.Indices.CreateAsync("documents", d => d
.Map(m => m.AutoMap<Document>()));
var indexDocument = await client
.IndexDocumentAsync(new Document {Id = 1, Brand = "Tommy", Category = "men"});
var indexDocument2 = await client
.IndexDocumentAsync(new Document {Id = 2, Brand = "Diesel", Category = "men"});
var indexDocument3 = await client
.IndexDocumentAsync(new Document {Id = 3, Brand = "Boss", Category = "men"});
var refreshAsync = client.Indices.RefreshAsync();
var searchResponse = await client.SearchAsync<Document>(s => s
.Query(q => q.MatchAll())
.Aggregations(a => a
.Terms("brand", t => t
.Field(f => f.Brand.Suffix("keyword")))));
var brands = searchResponse.Aggregations.Terms("brand");
foreach (var bucket in brands.Buckets)
{
Console.WriteLine(bucket.Key);
}
}
}
Prints:
Boss
Diesel
Tommy
Hope that helps.