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Elasticsearch.Net and NEST: the .NET clients [5.x] » Client Concepts - NEST » Index Name Inference
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Index Name Inferenceedit

Many endpoints within the Elasticsearch API expect to receive one or more index names as part of the request in order to know what index/indices a request should operate on.

NEST has a number of ways in which an index name can be specified

Default Index name on Connection Settingsedit

A default index name can be specified on ConnectionSettings using .DefaultIndex(). This is the default index name to use when no other index name can be resolved for a request

var settings = new ConnectionSettings()
    .DefaultIndex("defaultindex");
var resolver = new IndexNameResolver(settings);
var index = resolver.Resolve<Project>();
index.Should().Be("defaultindex");

Mapping an Index name for POCOsedit

A index name can be mapped for CLR types using .MapDefaultTypeIndices() on ConnectionSettings.

var settings = new ConnectionSettings()
    .MapDefaultTypeIndices(m => m
        .Add(typeof(Project), "projects")
    );

var resolver = new IndexNameResolver(settings);

var index = resolver.Resolve<Project>();

index.Should().Be("projects");

Mapping an Index name for POCOsedit

An index name for a POCO provided using .MapDefaultTypeIndices() will take precedence over the default index name

var settings = new ConnectionSettings()
    .DefaultIndex("defaultindex")
    .MapDefaultTypeIndices(m => m
        .Add(typeof(Project), "projects")
    );

var resolver = new IndexNameResolver(settings);

var index = resolver.Resolve<Project>();

index.Should().Be("projects");

Explicitly specifying Index name on the requestedit

For API calls that expect an index name, the index name can be explicitly provided on the request

Uri requestUri = null;

var client = TestClient.GetInMemoryClient(s=>s.OnRequestCompleted(r => { requestUri = r.Uri; }));

var response = client.Search<Project>(s => s.Index("some-other-index")); 

requestUri.Should().NotBeNull();

requestUri.LocalPath.Should().StartWith("/some-other-index/");

Provide the index name on the request

When an index name is provided on a request, it will take precedence over the default index name and any index name specified for the POCO type using .MapDefaultTypeIndices()

var client = TestClient.GetInMemoryClient(s=>
    new ConnectionSettings()
        .DefaultIndex("defaultindex")
        .MapDefaultTypeIndices(m => m
            .Add(typeof(Project), "projects")
        )
);

var response = client.Search<Project>(s => s.Index("some-other-index")); 

response.ApiCall.Uri.Should().NotBeNull();

response.ApiCall.Uri.LocalPath.Should().StartWith("/some-other-index/");

Provide the index name on the request

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