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Find 13: New language routing

In order to optimize indexing performance, and increase query precision, indexing documents should be done by specifying language routing. The use of language routing, when indexing, does not require any changes when querying. The only effect language routing has on querying is that it increases query precision. This is done by reducing the number of false positive matches, as documents only are analyzed for a specific language. Previously, all documents were analyzed for all available languages supported, sometimes causing noise when stemming rules for one language collided with stemming rules for another.

Adding language routing on any type of object

Adding language routing for any type of object can be done in different ways.


One option is to use LanguageRoutingAttribute on the property, and set it to the desired language when initializing the object.

public class WithLanguageRoutingAttribute
     public string Id { get; set; } 
     public LanguageRouting LanguageRouting { get; set; } 
var indexedObject = new WithLanguageRoutingAttribute()

     Id = "123", 
     LanguageRouting = new LanguageRouting(Language.Swedish) 


Another option is to use the conventions API in Find.

client.Conventions.ForInstancesOf<WithLanguageRouting>().LanguageRoutingIs(x => x.LanguageRouting);

CMS integration

The Find CMS integration automatically adds language routing support for content implementing ILocale. Most content base type, like PageData, ProductContent, NodeContent, and VariationContent, all implements ILocale. The behavior can be changed by either using conventions, or by overriding LanguageRoutingFactory.


The following example changes the behavior for all content implementing ILocale, to store the documents in the old way. It’s not recommended to do this, because it prevents the performance improvements.

client.Conventions.ForInstancesOf<ILocale>().LanguageRoutingIs(x => null);

This example changes the behavior only for MediaData. You might want to do this for some specific content types, if it’s necessary to analyze the content using all analyzers.

client.Conventions.ForInstancesOf<MediaData>().LanguageRoutingIs(x => null);


A LanguageRoutingFactory is, by default, used for all ILocale content, to create language routing for content that implements ILocale. It’s possible to change the default behavior by creating your own factory that inherits from LanguageRoutingFactory, and override any of the protected virtual methods. You also need to register your language routing factory using a configurable module.

public class MyFindInitializationModule : IConfigurableModule
     public void Initialize(InitializationEngine context)
     public void Uninitialize(InitializationEngine context)
     public void ConfigureContainer(ServiceConfigurationContext context)
         context.Services.AddSingleton<LanguageRoutingFactory, MyLanguageRoutingFactory>();
The following example changes the behaviour, to use all analyzers instead of the “standard” analyzer, for all content which uses a language we can’t map to any analyzer.
public class MyLanguageRoutingFactory : LanguageRoutingFactory
     public override LanguageRouting CreateLanguageRouting(ILocale locale)
         var languageRouting = base.CreateLanguageRouting(locale);
         if (languageRouting.FieldSuffix == Language.None.FieldSuffix)
             return null;
         return languageRouting;

Reindex the site after upgrade to Find 13

The changes in the language routing make it necessary to reindex the site after upgrading to Find 13. The site will work directly when you start the site, before the content has been reindexed. It will work because queries will still hit the content that hasn’t been indexed using the language routing.

The problem (if site isn’t reindexed) will occur when content is reindexed after being triggered from a content event. The content might be stored in a different way as before, which might make the old content continue to exist. You can end up having the same content stored twice, but in different versions.

Conclusion: After upgrading to Find 13, reindex the whole site as soon as possible.

Apr 03, 2018

K Khan
( By K Khan, 4/3/2018 7:48:06 PM)


K Khan
( By K Khan, 4/3/2018 7:52:09 PM)

Am i Correct in understanding? that conventions can be used with Commerce objects also as Products and Variants?

( 4/4/2018 7:33:27 AM)

K Khan, You are correct. Commerce objects like products and variants implements ILocale, and will use language routing by default. You can override the behaviour if needed.

Magnus Rahl
( By Magnus Rahl, 4/4/2018 8:43:35 AM)

A Find 13 compatible EPiServer.Find.Commerce is in the making, hopefully it can be released next week. Then you will be able to use Find 13 in applications using Find.Commerce as well.

Cristi Rusu
( By Cristi Rusu, 5/11/2018 11:39:19 AM)

I tried using "client.Conventions.ForInstancesOf().LanguageRoutingIs(x => null);" but the indexing job throws "Object reference not set to an instance of an object.".

Did anyone have better luck using it?

( By dada, 5/21/2018 9:38:25 AM)

This doesn't throw an error but does it do what I expect?
client.Instance.Conventions.ForInstancesOf().LanguageRoutingIs(x => new LanguageRouting(Language.None));

karthikeyan ponnusamy
( By karthikeyan ponnusamy, 8/20/2018 4:39:24 PM)

indexItem.LanguageRouting = new LanguageRouting(findclient.Settings.Languages.GetSupportedLanguage(language));

I try to index my custom model after setting the languagerouting it throws an error 

"Object reference not set to an instance of an object".


  at EPiServer.Find.ClientConventions.CompositeLanguageRoutingConvention.GetLanguageRouting(Object instance)
   at EPiServer.Find.Client.Index(Object objectToIndex, Action`1 commandAction)
   at EPiServer.Find.Client.Index(Object objectToIndex)

Son Do
( By Son Do, 8/22/2018 7:05:47 AM)

I moved Karthikeyan's question to related Forum thread

( 4/18/2019 7:36:58 AM)

Does this use the sharding functionality from Elastic Search? The reason I'm wondering is that I first expected to only get search hits from a single language back when using language routing, but I'm seeing results for multiple languages and I need to add a filter for it. Which I don't mind, but I thought the language routing feature was using the sharding in Elastic Search to only have to care about a single language.

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