using-sharparchitecture-with-nhibernate.search-(lucene.net).rst

S#arp Architecture with NHibernate.Search

Note

Do not use this with NHibernate Configuration Cache:

NHibernateSession.ConfigurationCache = new NHibernateConfigurationFileCache();

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 
{
    private readonly IContractRepositorycontractRepository;

    public class SearchController : Controller
    {
        public LuceneSupplierController(IContractRepositorycontractRepository)
        {
            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 );
        }
    }
}

• 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

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.