Elasticsearch NEST client creating multi-field fields with completion

Question

I am trying to create some completion suggesters on some of my fields. My document class looks like this:

[ElasticType(Name = "rawfiles", IdProperty = "guid")]
public class RAW
{
    [ElasticProperty(OmitNorms = true, Index = FieldIndexOption.NotAnalyzed, Type = FieldType.String, Store = true)]
    public string guid { get; set; }

    [ElasticProperty(OmitNorms = true, Index = FieldIndexOption.Analyzed, Type = FieldType.String, Store = true, IndexAnalyzer = "def_analyzer", SearchAnalyzer = "def_analyzer_search", AddSortField = true)]
    public string filename { get; set; }

    [ElasticProperty(OmitNorms = true, Index = FieldIndexOption.Analyzed, Type = FieldType.String, Store = true, IndexAnalyzer = "def_analyzer", SearchAnalyzer = "def_analyzer_search")]
    public List<string> tags { get { return new List<string>(); } }
}

And here is how I am trying to create the completion fields

public bool CreateMapping(ElasticClient client, string indexName)
{
    IIndicesResponse result = null;
    try
    {
        result = client.Map<RAW>(
                c => c.Index(indexName)
                    .MapFromAttributes()
                    .AllField(f => f.Enabled(false))
                    .SourceField(s => s.Enabled())
                    .Properties(p => p
                        .Completion(s => s.Name(n => n.tags.Suffix("comp"))
                                    .IndexAnalyzer("standard")
                                    .SearchAnalyzer("standard")
                                    .MaxInputLength(20)
                                    .Payloads()
                                    .PreservePositionIncrements()
                                    .PreserveSeparators())
                        .Completion(s2 => s2.Name(n=>n.filename.Suffix("comp"))
                                    .IndexAnalyzer("standard")
                                    .SearchAnalyzer("standard")
                                    .MaxInputLength(20)
                                    .Payloads()
                                    .PreservePositionIncrements()
                                    .PreserveSeparators())
                        )
                   );
    }
    catch (Exception)
    {

    }

    return result != null && result.Acknowledged;
}

My problem is that this is only creating a single completion field named "comp". I was under the impression that this will create two completion fields, one named filename.comp and the other named tags.comp.

I then tried the answer on this SO question but this complicated the matter even worse as now my two fields were mapped as a completion field only.

Just to be clear, I want to create a multi-field (field) that has a data, sort and completion fileds. Much like the one in this example

Answer 1

This is how you can reproduce auto-complete example from attached by you article.

My simple class(we are going to implement auto-complete on Name property)

public class Document
{
    public int Id { get; set; }
    public string Name { get; set; }
}

To create multi field mapping in NEST we have to define mapping in such manner:

var indicesOperationResponse = client.CreateIndex(descriptor => descriptor
    .Index(indexName)
    .AddMapping<Document>(m => m
        .Properties(p => p.MultiField(mf => mf
            .Name(n => n.Name)
            .Fields(f => f
                .String(s => s.Name(n => n.Name).Index(FieldIndexOption.Analyzed))
                .String(s => s.Name(n => n.Name.Suffix("sortable")).Index(FieldIndexOption.NotAnalyzed))
                .String(s => s.Name(n => n.Name.Suffix("autocomplete")).IndexAnalyzer("shingle_analyzer"))))))
    .Analysis(a => a
        .Analyzers(b => b.Add("shingle_analyzer", new CustomAnalyzer
        {
            Tokenizer = "standard",
            Filter = new List<string> {"lowercase", "shingle_filter"}
        }))
        .TokenFilters(b => b.Add("shingle_filter", new ShingleTokenFilter
        {
            MinShingleSize = 2,
            MaxShingleSize = 5
        }))));

Let's index some documents:

client.Index(new Document {Id = 1, Name = "Tremors"});
client.Index(new Document { Id = 2, Name = "Tremors 2: Aftershocks" });
client.Index(new Document { Id = 3, Name = "Tremors 3: Back to Perfection" });
client.Index(new Document { Id = 4, Name = "Tremors 4: The Legend Begins" });
client.Index(new Document { Id = 5, Name = "True Blood" });
client.Index(new Document { Id = 6, Name = "Tron" });
client.Index(new Document { Id = 7, Name = "True Grit" });
client.Index(new Document { Id = 8, Name = "Land Before Time" });
client.Index(new Document { Id = 9, Name = "The Shining" });
client.Index(new Document { Id = 10, Name = "Good Burger" });

client.Refresh();

Now, we are ready to write prefix query :)

var searchResponse = client.Search<Document>(s => s
    .Query(q => q
        .Prefix("name.autocomplete", "tr"))
    .SortAscending(sort => sort.Name.Suffix("sortable")));

This query will get us

Tremors 2: Aftershocks
Tremors 3: Back to Perfection
Tremors 4: The Legend Begins
Tron
True Blood
True Grit

Hope this will help you.

Recently, guys from NEST prepared great tutorial about NEST and elasticsearch. There is a part about suggestions, it should be really useful for you.