Customizing search

This topic describes how to customize and extend the search in Episerver Commerce by for instance adding index fields and creating new search indexers for specific purposes. See also Creating a Search Provider.

Classes in this topic are available in the following namespaces:

• Mediachase.Search
• Mediachase.Search.Extensions
• Mediachase.Search.Extensions.Indexers

Adding index fields

The process of adding a new field can differ depending on the provider you use and where the data is coming from. Here, we explain the steps for adding a field for the catalog index using Lucene and SOLR providers.

When using Lucene, if you want to add a meta-field to be searchable, go to the meta-field configuration in Commerce Manager and mark it as searchable; the field is automatically added to the index.

When using SOLR, add that field to the SOLR configuration file, which is located in APACHERROOT\solr\catalog\conf\catalog.schema.xml.

Example: adding an index field to the SOLR Schema

<field name="MyNewField" type="string" indexed="true" stored="true" multiValued="true" />

To add a field programmatically in the case when data comes from an external data source or needs to be computed, create a new class that inherits the existing CatalogIndexer.

Example: adding a custom index class

public class MyCatalogIndexer : Mediachase.Search.Extensions.Indexers.CatalogIndexBuilder
{
/// <summary>
/// Called when catalog entry is indexed. Override this method to add some extra fields.
/// </summary>
/// <param name="document">The document.</param>
/// <param name="entry">The entry.</param>
/// <param name="language"></param>
protected override void OnCatalogEntryIndex(ref SearchDocument document, CatalogEntryDto.CatalogEntryRow entry, string language)
  {
  // Example, add all apple products as featured
  if(entry.Name.Contains("apple"))
    document.Add(new SearchField("featured", true));
    base.OnCatalogEntryIndex(ref document, entry, language);
  }
}

Creating a search indexer

Search Indexer is a component that is responsible for assembling data into documents that Search Provider can then index. It typically connects subsystems like Catalogs, gets a list of changes and submits it to the search provider.

By default Episerver Commerce indexes catalog data via the the BaseCatalogIndexBuilder class or an inheriting class. However, third party implementations may implement ISearchIndexBuilder instead of extending the BaseCatalogIndexBuilder.

/// <summary>
/// Search Index Builder Interface.
/// </summary>
public interface ISearchIndexBuilder
{
    /// <summary>
    /// An event handler for progress message events.
    /// </summary>
    event SearchIndexHandler SearchIndexMessage;

    /// <summary>
    /// Gets or sets the manager.
    /// </summary>
    /// <value>The manager.</value>
    SearchManager Manager { get; set; }

    /// <summary>
    /// Gets or sets the build indexer.
    /// </summary>
    /// <value>The build indexer.</value>
    IndexBuilder Indexer { get; set; }

    /// <summary>
    /// Builds the index.
    /// </summary>
    /// <param name="rebuild">if set to <c>true</c> the full rebuild will be done, if not. The last build date will be used.</param>
    void BuildIndex(bool rebuild);

    /// <summary>
    /// Updates the specified items in the index.
    /// </summary>
    /// <param name="itemIds">The ids of the items to update.</param>
    /// <returns>True if successful; otherwise, false.</returns>        
    bool UpdateIndex(IEnumerable<int> itemIds);
}

The updated catalog event system uses the UpdateIndex method and calls it for any changed or deleted catalog entries. The parameter enumerates catalog entry IDs of changed or delete entries, and the implementation is expected to update the search indexes appropriately for these entries.

If a transient error occurs (such as a network error when accessing a remote service), UpdateIndex should return false. The system may then retry the same batch of updates again later. If a non-transient error occurs, then the implementation should throw an exception.

An implementation of ISearchIndexBuilder should throw an exception from UpdateIndex if the updated event system is not supported, and scheduled tasks is used to execute BuildIndex.

Related topic

• Search in Episerver CMS