Using Completion Suggester with NEST

completion-suggester.cs

void Main()
{
    var indexName = "stackoverflow";
    var node = new SingleNodeConnectionPool(new Uri("http://localhost:9200"));
    var settings = new ConnectionSettings(node)
        .InferMappingFor<Question>(m => m
            .IndexName(indexName)
        )
        .PrettyJson()
        .DisableDirectStreaming()
        .OnRequestCompleted(callDetails =>
            {
                // log out the request
                if (callDetails.RequestBodyInBytes != null)
                {
                    Console.WriteLine(
                        $"{callDetails.HttpMethod} {callDetails.Uri} \n" +
                        $"{Encoding.UTF8.GetString(callDetails.RequestBodyInBytes)}");
                }
                else
                {
                    Console.WriteLine($"{callDetails.HttpMethod} {callDetails.Uri}");
                }

                Console.WriteLine();

                // log out the response
                if (callDetails.ResponseBodyInBytes != null)
                {
                    Console.WriteLine($"Status: {callDetails.HttpStatusCode}\n" +
                             $"{Encoding.UTF8.GetString(callDetails.ResponseBodyInBytes)}\n" +
                             $"{new string('-', 30)}\n");
                }
                else
                {
                    Console.WriteLine($"Status: {callDetails.HttpStatusCode}\n" +
                             $"{new string('-', 30)}\n");
                }
            });


    var client = new ElasticClient(settings);

    if (client.IndexExists(indexName).Exists)
    {
        client.DeleteIndex(indexName);
    }

    var createIndexResponse = client.CreateIndex(indexName, c => c
        .Mappings(m => m
            .Map<Question>(u => u
                .AutoMap()
            )
        )
    );

    var questions = new[] {
        new Question 
        {
            Title = "Elasticsearch for .NET",
            TitleSuggest = new CompletionField
            {
                Input = new [] { "Elasticsearch.Net", "NEST" } 
            }
        },
        new Question
        {
            Title = "The Elastic stack",
            TitleSuggest = new CompletionField
            {
                Input = new [] { "Elasticsearch", "Logstash", "Kibana", "Beats" }
            }
        },
        new Question
        {
            Title = "Kibana",
            TitleSuggest = new CompletionField
            {
                Input = new [] { "Kibana", "UI" }
            }
        }
    };
    
    client.IndexMany(questions);
    
    client.Refresh(indexName);

    var input = "el";

    var response = client.Search<Question>(s => s
        .Suggest(su => su
            .Completion("title", cs => cs
                .Field(f => f.TitleSuggest)
                .Prefix(input)
                .Fuzzy(f => f
                    .Fuzziness(Fuzziness.Auto)
                )
                .Size(5)
            )
        )
    );

    var suggestions =
        from suggest in response.Suggest["title"]
        from option in suggest.Options
        select new
        {
            Id = option.Id,
            Text = option.Text,
            Score = option.Score,
            Source = option.Source
        };

    
}

public class Question
{
    public string Title { get; set; }

    public CompletionField TitleSuggest { get; set; }
}