Index name inference
editIndex name inference
editMany 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 the index name(s) can be specified
Default Index name on Connection Settings
editA 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 client = new ElasticClient(settings); var searchResponse = client.Search<Project>();
will send a search request to the API endpoint
"http://localhost:9200/defaultindex/_search"
Index name for a .NET type
editAn index name can be mapped for a Plain Old CLR Object (POCO) using .DefaultMappingFor<T>()
on ConnectionSettings
var settings = new ConnectionSettings() .DefaultMappingFor<Project>(m => m .IndexName("projects") ); var client = new ElasticClient(settings); var searchResponse = client.Search<Project>();
will send a search request to the API endpoint
"http://localhost:9200/projects/_search"
.DefaultMappingFor<T>()
can also be used to specify other defaults for a POCO, including
property names, property to use for the document id, amongst others.
An index name for a POCO provided using .DefaultMappingFor<T>()
will take precedence over
the default index name set on ConnectionSettings
. This way, the client can be configured with a default index to use if no
index is specified, and a specific index to use for different POCO types.
var settings = new ConnectionSettings() .DefaultIndex("defaultindex") .DefaultMappingFor<Project>(m => m .IndexName("projects") ); var client = new ElasticClient(settings); var projectSearchResponse = client.Search<Project>();
a default index to use, when no other index can be inferred |
|
a index to use when |
will send a search request to the API endpoint
"http://localhost:9200/projects/_search"
but
var objectSearchResponse = client.Search<object>();
will send a search request to the API endpoint
"http://localhost:9200/defaultindex/_search"
Explicitly specifying Index name on the request
editFor API calls that expect an index name, an index name can be explicitly provided on the request
var settings = new ConnectionSettings(); var client = new ElasticClient(settings); var response = client.Search<Project>(s => s .Index("some-other-index") );
will send a search request to the API endpoint
"http://localhost:9200/some-other-index/_search"
When an index name is provided on a request, it will take precedence over the default
index name specified on ConnectionSettings
, and any index name specified for the POCO
using .DefaultMappingFor<T>()
. The following example will send a search request
to the same API endpoint as the previous example
var settings = new ConnectionSettings() .DefaultIndex("defaultindex") .DefaultMappingFor<Project>(m => m .IndexName("projects") ); var client = new ElasticClient(settings); var response = client.Search<Project>(s => s .Index("some-other-index") );
In summary, the order of precedence for determining the index name for a request is
- Index name specified on the request
-
Index name specified for the generic type parameter in the request using
.DefaultMappingFor<T>()
-
Default index name specified on
ConnectionSettings
If no index can be determined for a request that requires an index, the client will throw an exception to indicate that this is the case.