using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using Lucene.Net.Analysis.Standard;
using Lucene.Net.Documents;
using Lucene.Net.Index;
using Lucene.Net.QueryParsers;
using Lucene.Net.Search;
using Lucene.Net.Store;
using MediaBrowser.Controller;
using MediaBrowser.Controller.Entities;
using MediaBrowser.Controller.Library;
using MediaBrowser.Model.Logging;
namespace MediaBrowser.Server.Implementations.Library
{
///
/// Class LuceneSearchEngine
/// http://www.codeproject.com/Articles/320219/Lucene-Net-ultra-fast-search-for-MVC-or-WebForms
///
public class LuceneSearchEngine : ILibrarySearchEngine, IDisposable
{
public LuceneSearchEngine(IServerApplicationPaths serverPaths, ILogManager logManager)
{
//string luceneDbPath = serverPaths.DataPath + "\\SearchIndexDB";
//if (!System.IO.Directory.Exists(luceneDbPath))
// System.IO.Directory.CreateDirectory(luceneDbPath);
//else if(File.Exists(luceneDbPath + "\\write.lock"))
// File.Delete(luceneDbPath + "\\write.lock");
//LuceneSearch.Init(luceneDbPath, logManager.GetLogger("Lucene"));
//BaseItem.LibraryManager.LibraryChanged += LibraryChanged;
}
public void LibraryChanged(object source, ChildrenChangedEventArgs changeInformation)
{
Task.Run(() =>
{
if (changeInformation.ItemsAdded.Count + changeInformation.ItemsUpdated.Count > 0)
{
LuceneSearch.AddUpdateLuceneIndex(changeInformation.ItemsAdded.Concat(changeInformation.ItemsUpdated));
}
if (changeInformation.ItemsRemoved.Count > 0)
{
LuceneSearch.RemoveFromLuceneIndex(changeInformation.ItemsRemoved);
}
});
}
public void AddItemsToIndex(IEnumerable items)
{
LuceneSearch.AddUpdateLuceneIndex(items);
}
///
/// Searches items and returns them in order of relevance.
///
/// The items.
/// The search term.
/// IEnumerable{BaseItem}.
/// searchTerm
public IEnumerable Search(IEnumerable items, string searchTerm)
{
if (string.IsNullOrEmpty(searchTerm))
{
throw new ArgumentNullException("searchTerm");
}
var hits = LuceneSearch.Search(searchTerm, items.Count());
//return hits;
return hits.Where(searchHit => items.Any(p => p.Id == searchHit.Id));
}
public void Dispose()
{
//BaseItem.LibraryManager.LibraryChanged -= LibraryChanged;
//LuceneSearch.CloseAll();
}
}
public static class LuceneSearch
{
private static ILogger logger;
private static string path;
private static object lockOb = new object();
private static FSDirectory _directory;
private static FSDirectory directory
{
get
{
if (_directory == null)
{
logger.Info("Opening new Directory: " + path);
_directory = FSDirectory.Open(path);
}
return _directory;
}
set
{
_directory = value;
}
}
private static IndexWriter _writer;
private static IndexWriter writer
{
get
{
if (_writer == null)
{
logger.Info("Opening new IndexWriter");
_writer = new IndexWriter(directory, analyzer, IndexWriter.MaxFieldLength.UNLIMITED);
}
return _writer;
}
set
{
_writer = value;
}
}
private static Dictionary bonusTerms;
public static void Init(string path, ILogger logger)
{
logger.Info("Lucene: Init");
bonusTerms = new Dictionary();
bonusTerms.Add("Name", 2);
bonusTerms.Add("Overview", 1);
// Optimize the DB on initialization
// TODO: Test whether this has..
// Any effect what-so-ever (apart from initializing the indexwriter on the mainthread context, which makes things a whole lot easier)
// Costs too much time
// Is heavy on the CPU / Memory
LuceneSearch.logger = logger;
LuceneSearch.path = path;
writer.Optimize();
}
private static StandardAnalyzer analyzer = new StandardAnalyzer(Lucene.Net.Util.Version.LUCENE_30);
private static Searcher searcher = null;
private static Document createDocument(BaseItem data)
{
Document doc = new Document();
doc.Add(new Field("Id", data.Id.ToString(), Field.Store.YES, Field.Index.NO));
doc.Add(new Field("Name", data.Name, Field.Store.YES, Field.Index.ANALYZED) { Boost = 2 });
doc.Add(new Field("Overview", data.Overview != null ? data.Overview : "", Field.Store.YES, Field.Index.ANALYZED));
return doc;
}
private static void Create(BaseItem item)
{
lock (lockOb)
{
try
{
if (searcher != null)
{
try
{
searcher.Dispose();
}
catch (Exception e)
{
logger.ErrorException("Error in Lucene while creating index (disposing alive searcher)", e, item);
}
searcher = null;
}
_removeFromLuceneIndex(item);
_addToLuceneIndex(item);
}
catch (Exception e)
{
logger.ErrorException("Error in Lucene while creating index", e, item);
}
}
}
private static void _addToLuceneIndex(BaseItem data)
{
// Prevent double entries
var doc = createDocument(data);
writer.AddDocument(doc);
}
private static void _removeFromLuceneIndex(BaseItem data)
{
var query = new TermQuery(new Term("Id", data.Id.ToString()));
writer.DeleteDocuments(query);
}
public static void AddUpdateLuceneIndex(IEnumerable items)
{
foreach (var item in items)
{
logger.Info("Adding/Updating BaseItem " + item.Name + "(" + item.Id.ToString() + ") to/on Lucene Index");
Create(item);
}
writer.Commit();
writer.Flush(true, true, true);
}
public static void RemoveFromLuceneIndex(IEnumerable items)
{
foreach (var item in items)
{
logger.Info("Removing BaseItem " + item.Name + "(" + item.Id.ToString() + ") from Lucene Index");
_removeFromLuceneIndex(item);
}
writer.Commit();
writer.Flush(true, true, true);
}
public static IEnumerable Search(string searchQuery, int maxHits)
{
var results = new List();
lock (lockOb)
{
try
{
if (searcher == null)
{
searcher = new IndexSearcher(directory, true);
}
BooleanQuery finalQuery = new BooleanQuery();
MultiFieldQueryParser parser = new MultiFieldQueryParser(Lucene.Net.Util.Version.LUCENE_30, new string[] { "Name", "Overview" }, analyzer, bonusTerms);
string[] terms = searchQuery.Split(new[] { " " }, StringSplitOptions.RemoveEmptyEntries);
foreach (string term in terms)
finalQuery.Add(parser.Parse(term.Replace("~", "") + "~0.75"), Occur.SHOULD);
foreach (string term in terms)
finalQuery.Add(parser.Parse(term.Replace("*", "") + "*"), Occur.SHOULD);
logger.Debug("Querying Lucene with query: " + finalQuery.ToString());
long start = DateTime.Now.Ticks;
var searchResult = searcher.Search(finalQuery, maxHits);
foreach (var searchHit in searchResult.ScoreDocs)
{
Document hit = searcher.Doc(searchHit.Doc);
results.Add(BaseItem.LibraryManager.GetItemById(Guid.Parse(hit.Get("Id"))));
}
long total = DateTime.Now.Ticks - start;
float msTotal = (float)total / TimeSpan.TicksPerMillisecond;
logger.Debug(searchResult.ScoreDocs.Length + " result" + (searchResult.ScoreDocs.Length == 1 ? "" : "s") + " in " + msTotal + " ms.");
}
catch (Exception e)
{
logger.ErrorException("Error while searching Lucene index", e);
}
}
return results;
}
public static void CloseAll()
{
logger.Debug("Lucene: CloseAll");
if (writer != null)
{
logger.Debug("Lucene: CloseAll - Writer is alive");
writer.Flush(true, true, true);
writer.Commit();
writer.WaitForMerges();
writer.Dispose();
writer = null;
}
if (analyzer != null)
{
logger.Debug("Lucene: CloseAll - Analyzer is alive");
analyzer.Close();
analyzer.Dispose();
analyzer = null;
}
if (searcher != null)
{
logger.Debug("Lucene: CloseAll - Searcher is alive");
searcher.Dispose();
searcher = null;
}
if (directory != null)
{
logger.Debug("Lucene: CloseAll - Directory is alive");
directory.Dispose();
directory = null;
}
}
}
}