Using sharparchitecture with nhibernate.search (lucene.net)

Note

Do not use this with NHibernate Configuration Cache:

NHibernateSession.ConfigurationCache = new NHibernateConfigurationFileCache();

Pre-Requisite Reading

I really recommend Hibernate Search in Action, you can really make queries do some neat things that aren't covered in this tutorial. It will, however, get you up and running quickly.

NuGet Install

Install-Package NHibernate.Search

(This used to be a big deal, building from source, etc.)

Configuring and Building the Index

Maintaining an index in Lucene is easy. There's a configuration setting to keep any deletes, inserts or updates current in the index, and a way to build the index from an existing dataset from scratch. You usually need both unless you're starting on a project from scratch, but even so, it is nice to have a way to build an index in case the existing index gets corrupted.

This example will assume you've created a folder in the root of your MVC project, and have given the ASP.NET security guy full permissions.

Open up your root Web.Config, add the following right above :

Right below add the following:

<nhs-configuration xmlns='urn:nhs-configuration-1.0'>
    <search-factory>
        <property  name="hibernate.search.default.indexBase">~\LuceneIndex</property>
    </search-factory>
</nhs-configuration>

Navigate to your NHibernate.Config, before add:

    <listener class='NHibernate.Search.Event.FullTextIndexEventListener, NHibernate.Search' type='post-insert'/>
    <listener class='NHibernate.Search.Event.FullTextIndexEventListener, NHibernate.Search' type='post-update'/>
    <listener class='NHibernate.Search.Event.FullTextIndexEventListener, NHibernate.Search' type='post-delete'/>

Add a Search Repository

In "Northwind.Infrastructure" add a repository called "ContractRepository.cs" (the example assumes you have an object you want to search over called contract):

public interface IContractRepository
{
    IList<Contract> Query(string q)
    void BuildSearchIndex();
}

Let's add a method to this repository that will create the initial index, if an index already exists, it will be deleted. We'll iterate through all the Suppliers to accomplish this:

    public void BuildSearchIndex()
    {
        FSDirectory entityDirectory = null;
        IndexWriter writer = null;

        var entityType = typeof(Contract);

        var indexDirectory = new DirectoryInfo(GetIndexDirectory());

        if (indexDirectory.Exists)
        {
            indexDirectory.Delete(true);
        }

        try
        {
            var dir = new DirectoryInfo(Path.Combine(indexDirectory.FullName, entityType.Name));
            entityDirectory = FSDirectory.Open(dir);
            writer = new IndexWriter(entityDirectory, new StandardAnalyzer(Lucene.Net.Util.Version.LUCENE_29), true, IndexWriter.MaxFieldLength.UNLIMITED);
        }
        finally
        {
            if (entityDirectory != null)
            {
                entityDirectory.Close();
            }

            if (writer != null)
            {
                writer.Close();
            }
        }

        var fullTextSession = Search.CreateFullTextSession(this.Session);

        // Iterate through contracts and add them to Lucene's index
        foreach (var instance in Session.CreateCriteria(typeof(Contract)).List<Contract>())
        {
            fullTextSession.Index(instance);
        }
    }

    private static string GetIndexDirectory()
    {
        INHSConfigCollection nhsConfigCollection = CfgHelper.LoadConfiguration();
        string property = nhsConfigCollection.DefaultConfiguration.Properties["hibernate.search.default.indexBase"];
        var fi = new FileInfo(property);
        return Path.Combine(AppDomain.CurrentDomain.BaseDirectory, fi.Name); 
    }

Finally, we'll add a method to query the index:

    private static string GetIndexDirectory()
    {
        INHSConfigCollection nhsConfigCollection = CfgHelper.LoadConfiguration();
        string property = nhsConfigCollection.DefaultConfiguration.Properties["hibernate.search.default.indexBase"];
        var fi = new FileInfo(property);
        return Path.Combine(AppDomain.CurrentDomain.BaseDirectory, fi.Name); 
    }

Add Search Controller

namespace Northwind.Web.Controllers { public class SearchController : Controller { public LuceneSupplierController(IContractRepository contractRepository) { this.contractRepository= contractRepository; }

    public ActionResult BuildSearchIndex() {
        contractRepository.BuildSearchIndex();
        return RedirectToAction("Index", "Home");            
    }

    public ActionResult Search(string query) {
        List<Contract> Contracts = contractRepository.Query(query).ToList();
        return View(Contracts );
    }

   private readonly IContractRepositorycontractRepository;
}

}

• Wire up a view to display the search results
• Navigate to localhost:portnumber/ContractController/BuildSearchIndex
• This will (quickly) build your index, it would be beneficial to pass status messages here
• You should see a Suppliers folder in the LuceneIndex folder of the project
• To verify the index, download Luke and point it to the LuceneIndex