CODEWITHSUNDEEP
elasticsearchnestelasticsearch.net
Hooman Bahreini
Hooman Bahreini

Reputation: 15559

How to read distance from Elasticsearch response

I am using Elasticsearch V6, NEST V6.

I am searching ES as below and I am using ScriptFields to calculate the distance and include it the result.

var searchResponse = _elasticClient.Search<MyDocument>(new SearchRequest<MyDocument>
{
    Query = new BoolQuery
    {
        Must = new QueryContainer[] { matchQuery },
        Filter = new QueryContainer[] { filterQuery },
    },
    Source = new SourceFilter
    {
        Includes = resultFields    // fields to be included in the result
    },
    ScriptFields = new ScriptField
    {
        Script = new InlineScript("doc['geoLocation'].planeDistance(params.lat, params.lng) * 0.001")   // divide by 1000 to convert to km
        {
            Lang = "painless",
            Params = new FluentDictionary<string, object>
            {
                { "lat", _center.Latitude },
                { "lng", _center.Longitude }
            }
        }
    }
});

Now, I am trying to read the search result and I am not sure how to read the distance from the response, this is what I have tried:

// this is how I read the Document, all OK here
var docs = searchResponse.Documents.ToList<MyDocument>();

// this is my attempt to read the distance from the result
var hits = searchResponse.Hits;
foreach (var h in hits)
{
    var d = h.Fields["distance"];
    // d is of type Nest.LazyDocument 
    // I am not sure how to get the distance value from object of type LazyDocument
}

While debugging I can see the distance value, I am just not sure how to read the value?

enter image description here

Upvotes: 0

Views: 873

Answers (1)

Hooman Bahreini
Hooman Bahreini

Reputation: 15559

I found the answer here

To read search document and distance:

foreach (var hit in searchResponse.Hits)
{
    MyDocument doc = hit.Source;    
    double distance = hit.Fields.Value<double>("distance");  
}

And if you are only interested in distance:

foreach (var fieldValues in searchResponse.Fields)
{
    var distance = fieldValues.Value<double>("distance");
}

Upvotes: 3

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