Table of Contents

Installation and first index

Install

dotnet add package LeanCorpus

Targets net10.0 and net11.0.

Index two documents

using Rowles.LeanCorpus.Document;
using Rowles.LeanCorpus.Document.Fields;
using Rowles.LeanCorpus.Index.Indexer;
using Rowles.LeanCorpus.Store;

using var dir = new MMapDirectory("./index");
using var writer = new IndexWriter(dir, new IndexWriterConfig());

var doc1 = new LeanDocument();
doc1.Add(new TextField("title", "The quick brown fox"));
doc1.Add(new StringField("id", "1"));
writer.AddDocument(doc1);

var doc2 = new LeanDocument();
doc2.Add(new TextField("title", "Lazy dogs and slow cats"));
doc2.Add(new StringField("id", "2"));
writer.AddDocument(doc2);

writer.Commit();

using Rowles.LeanCorpus.Search.Queries;
using Rowles.LeanCorpus.Search.Searcher;

using var searcher = new IndexSearcher(dir);
var hits = searcher.Search(new TermQuery("title", "fox"), topN: 10);

foreach (var hit in hits.ScoreDocs)
    Console.WriteLine($"docId={hit.DocId} score={hit.Score}");

What is on disk

The directory holds segment files (*.seg, *.dic, *.pos, *.fdt, *.fdx, *.nrm, etc.) and one or more segments_N commit files. See the architecture overview for details.

Native AOT

LeanCorpus is marked AOT-compatible for net10.0 and net11.0. The core library avoids reflection-based JSON metadata and is validated by a dedicated xUnit smoke test (run with ./devops aot) rather than the ASP.NET JSON API example.

The smoke test publishes src/examples/Rowles.LeanCorpus.Example.NativeAot for win-x64 with PublishAot=true, then runs the native executable through several code paths that have previously been problematic under AOT.

Note

If you use one of the optional compression libraries with Native AOT, call their Register() methods at startup:

Lz4Compression.Register();
SnappyCompression.Register();
ZstandardCompression.Register();

In standard .NET the module initialiser registers them automatically, but AOT may trim the initialiser.

Important

LeanCorpus does not support Blazor WASM. The segment-centric design requires a filesystem for memory-mapped I/O. Blazor Server and Blazor Hybrid are supported, as long as indexing happens server-side.

See also

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