Aggregation, suggestion in ElasticSearch (Nest, Elasticsearch.net) get complete object

Question

I'm quite new to elasticsearch, I am using NEST to query to elastic following is my code snippet.

var searchResults =
            elasticClient.Client.Search<T>(
            s => s
                    .Size(20)
                    .Fields(core)
                    .QueryString(String.Format("*{0}*", query)).MinScore(1).QueryString(String.Format("*{0}*", query.Replace(" ", "")))
                    .Highlight(h => h
                    .PreTags("<b>")
                    .PostTags("</b>")
                    .OnFields(f => f
                        .PreTags("<em>")
                        .PostTags("</em>")
                    )
                )
            );

var suggestResults = elasticClient.Client.Suggest<T>(s => s
                                        .Term("suggest", m => m
                                            .SuggestMode(SuggestMode.Always)
                                            .Text(query)
                                            .Size(10)
                                            .OnField(core)
                                        ));

var aggregation = elasticClient.Client.Search<T>(s => s
            .Aggregations(a => a
                .Terms("term_items", gh=>gh
                    .Field(p=>p.Town)
                    .Aggregations(gha=>gha
                        .SignificantTerms("bucket_agg", m => m
                            .Field(p => p.Town)
                            .Size(2)
                            .Aggregations(ma => ma.Terms("Town", t => t.Field(p => p.Town)))
                        )
                    )
                )
            )
);

I do get list of documents (list of my specified domain object) , but in case of suggest and aggregation it doesn't return domain object ?

I apologize in advanced and I hope you can point me to the correct direction.

I am looking for a way to implement in NEST.

Answer 1

To get to your aggregations you need to use the Aggs property of the result. According to the documentation:

The result of the aggregations are accessed from the Aggs property of the response using the key that was specified on the request...

In your example this would be "term_items". You are also doing a sub-aggregation, so these need to be extracted for each top-level aggregation, again using the key specified for the sub-aggregation - "bucket_agg". Your code should look something like

var agg = results.Aggs.Terms("term_items");
if (agg!= null && agg.Items.Count > 0)
{
    foreach (var termItemAgg in agg.Items)
    {
        // do something with the aggregations
        // the term is accessed using the Key property
        var term = termItemAgg.Key;

        // the count is accessed through the DocCount property
        var count = termItemAgg.Count;

        // now access the result of the sub-aggregation
        var bucketAgg = termItemAgg.Aggs.SignificantTerms("bucket_agg");

        // do something with your sub-aggregation results
    }
}

There is more detail in the documentation.

To get your suggestions you access the Suggestions property of your results object, using the key you specify when calling the ElasticClient.Suggest method. Something like

var suggestions = result.Suggestions["suggest"]
                .FirstOrDefault()
                .Options
                .Select(suggest => suggest.Payload)
                .ToList();

Hope this helps .