From a88ca3be28db329e87e4dd71bacd43a4d546ebce Mon Sep 17 00:00:00 2001
From: Robin <robalexclark@hotmail.com>
Date: Tue, 22 Oct 2024 08:55:44 +0100
Subject: [PATCH 1/2] Add metadata search to mongodb

---
 src/IntegrationTests/DatabaseTests.cs  |  2 +-
 src/Mongo/src/MongoVectorCollection.cs | 25 ++++++++++++++++++++++---
 2 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/src/IntegrationTests/DatabaseTests.cs b/src/IntegrationTests/DatabaseTests.cs
index 6b9e4e0..480a2a0 100644
--- a/src/IntegrationTests/DatabaseTests.cs
+++ b/src/IntegrationTests/DatabaseTests.cs
@@ -298,10 +298,10 @@ public async Task SimilaritySearchWithScores_Ok(SupportedDatabase database)
     }
 
     [TestCase(SupportedDatabase.InMemory)]
-    //[TestCase(SupportedDatabase.Chroma)]
     //[TestCase(SupportedDatabase.OpenSearch)]
     //[TestCase(SupportedDatabase.Postgres)]
     [TestCase(SupportedDatabase.SqLite)]
+    [TestCase(SupportedDatabase.Mongo)]
     //[TestCase(SupportedDatabase.DuckDb)]
     //[TestCase(SupportedDatabase.Weaviate)]
     //[TestCase(SupportedDatabase.Elasticsearch)]
diff --git a/src/Mongo/src/MongoVectorCollection.cs b/src/Mongo/src/MongoVectorCollection.cs
index 1537e12..e31e444 100644
--- a/src/Mongo/src/MongoVectorCollection.cs
+++ b/src/Mongo/src/MongoVectorCollection.cs
@@ -71,8 +71,27 @@ public async Task<VectorSearchResponse> SearchAsync(VectorSearchRequest request,
         };
     }
 
-    Task<List<Vector>> IVectorCollection.SearchByMetadata(Dictionary<string, object> filters, CancellationToken cancellationToken)
+    public async Task<List<Vector>> SearchByMetadata(Dictionary<string, object> filters, CancellationToken cancellationToken = default)
     {
-        throw new NotImplementedException();
+        filters = filters ?? throw new ArgumentNullException(nameof(filters));
+
+        var builder = Builders<Vector>.Filter;
+        var filterDefinitions = new List<FilterDefinition<Vector>>();
+
+        foreach (var kvp in filters)
+        {
+            // Assuming your Vector class has a Metadata field of type Dictionary<string, object>
+            var filter = builder.Eq($"Metadata.{kvp.Key}", kvp.Value);
+            filterDefinitions.Add(filter);
+        }
+
+        var combinedFilter = builder.And(filterDefinitions);
+
+        var results = await _mongoCollection
+            .Find(combinedFilter)
+            .ToListAsync(cancellationToken)
+            .ConfigureAwait(false);
+
+        return results;
     }
-}
+}
\ No newline at end of file

From f73459c746aa9a7f99975a400c6c86c9a638adad Mon Sep 17 00:00:00 2001
From: Robin <robalexclark@hotmail.com>
Date: Wed, 23 Oct 2024 08:34:59 +0100
Subject: [PATCH 2/2] Added coderabbit suggestions

---
 src/IntegrationTests/DatabaseTests.cs  | 27 +++++++++++++++++++++++++-
 src/Mongo/src/MongoVectorCollection.cs |  7 ++++++-
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/src/IntegrationTests/DatabaseTests.cs b/src/IntegrationTests/DatabaseTests.cs
index 480a2a0..37a19c5 100644
--- a/src/IntegrationTests/DatabaseTests.cs
+++ b/src/IntegrationTests/DatabaseTests.cs
@@ -1,5 +1,7 @@
 using LangChain.DocumentLoaders;
 using LangChain.Extensions;
+using StackExchange.Redis;
+using System;
 
 namespace LangChain.Databases.IntegrationTests;
 
@@ -336,7 +338,30 @@ public async Task MetadataSearch_Ok(SupportedDatabase database)
         var items = await vectorCollection.SearchByMetadata(filters);
 
         totalItems.Should().HaveCount(2);
+
         items.Should().HaveCount(1);
-        var vector = items.SingleOrDefault()?.Metadata?["color"].Should().Be("orange");
+        var result = items.Single();
+        result.Text.Should().Be("orange");
+        result.Metadata.Should().ContainKey("color");
+        result.Metadata?["color"].Should().Be("orange");
+    }
+
+    [TestCase(SupportedDatabase.InMemory)]
+    //[TestCase(SupportedDatabase.OpenSearch)]
+    //[TestCase(SupportedDatabase.Postgres)]
+    [TestCase(SupportedDatabase.SqLite)]
+    [TestCase(SupportedDatabase.Mongo)]
+    //[TestCase(SupportedDatabase.DuckDb)]
+    //[TestCase(SupportedDatabase.Weaviate)]
+    //[TestCase(SupportedDatabase.Elasticsearch)]
+    //[TestCase(SupportedDatabase.Milvus)]
+    public async Task SearchByMetadata_WithNullFilters_ThrowsArgumentException(SupportedDatabase database)
+    {
+        await using var environment = await StartEnvironmentForAsync(database);
+        var vectorCollection = await environment.VectorDatabase.GetOrCreateCollectionAsync(environment.CollectionName, dimensions: environment.Dimensions);
+
+        // Act & Assert
+        await vectorCollection.Invoking(v => v.SearchByMetadata(null!))
+            .Should().ThrowAsync<ArgumentNullException>();
     }
 }
\ No newline at end of file
diff --git a/src/Mongo/src/MongoVectorCollection.cs b/src/Mongo/src/MongoVectorCollection.cs
index e31e444..0da1a83 100644
--- a/src/Mongo/src/MongoVectorCollection.cs
+++ b/src/Mongo/src/MongoVectorCollection.cs
@@ -11,7 +11,7 @@ public class MongoVectorCollection(
     string? id = null)
 : VectorCollection(name, id), IVectorCollection
 {
-    private IMongoCollection<Vector> _mongoCollection = mongoContext.GetCollection<Vector>(name);
+    private readonly IMongoCollection<Vector> _mongoCollection = mongoContext.GetCollection<Vector>(name);
 
     public async Task<IReadOnlyCollection<string>> AddAsync(IReadOnlyCollection<Vector> items, CancellationToken cancellationToken = default)
     {
@@ -80,6 +80,11 @@ public async Task<List<Vector>> SearchByMetadata(Dictionary<string, object> filt
 
         foreach (var kvp in filters)
         {
+            if (kvp.Value == null)
+            {
+                throw new ArgumentException($"Metadata value for key '{kvp.Key}' cannot be null", nameof(filters));
+            }
+
             // Assuming your Vector class has a Metadata field of type Dictionary<string, object>
             var filter = builder.Eq($"Metadata.{kvp.Key}", kvp.Value);
             filterDefinitions.Add(filter);