聚合，ElasticSearch（Nest，Elasticsearch.net）中的建议获取完整的对象

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 .