Added persistent embedding cache

src/Server/Helper/SQLiteHelper.cs

@@ -0,0 +1,76 @@
+using System.Data;
+using System.Data.Common;
+using Microsoft.Data.Sqlite;
+using Server.Models;
+using MySql.Data.MySqlClient;
+using System.Configuration;
+
+namespace Server.Helper;
+
+public class SQLiteHelper : SqlHelper, IDisposable
+{
+    public SQLiteHelper(DbConnection connection, string connectionString) : base(connection, connectionString)
+    {
+        Connection = connection;
+        ConnectionString = connectionString;
+    }
+
+    public SQLiteHelper(EmbeddingSearchOptions options) : base(new SqliteConnection(options.ConnectionStrings.Cache), options.ConnectionStrings.Cache ?? "")
+    {
+        if (options.ConnectionStrings.Cache is null)
+        {
+            throw new ConfigurationErrorsException("Cache options must not be null when instantiating SQLiteHelper");
+        }
+        ConnectionString = options.ConnectionStrings.Cache;
+        Connection = new SqliteConnection(ConnectionString);
+    }
+
+    public override SQLiteHelper DuplicateConnection()
+    {
+        SqliteConnection newConnection = new(ConnectionString);
+        return new SQLiteHelper(newConnection, ConnectionString);
+    }
+
+    public override int ExecuteSQLCommandGetInsertedID(string query, object[] parameters)
+    {
+        lock (Connection)
+        {
+            EnsureConnected();
+            EnsureDbReaderIsClosed();
+            using DbCommand command = Connection.CreateCommand();
+
+            command.CommandText = query;
+            command.Parameters.AddRange(parameters);
+            command.ExecuteNonQuery();
+            command.CommandText = "SELECT last_insert_rowid();";
+            return Convert.ToInt32(command.ExecuteScalar());
+        }
+    }
+
+    public int BulkExecuteNonQuery(string sql, IEnumerable<object[]> parameterSets)
+    {
+        lock (Connection)
+        {
+            EnsureConnected();
+            EnsureDbReaderIsClosed();
+
+            using var transaction = Connection.BeginTransaction();
+            using var command = Connection.CreateCommand();
+
+            command.CommandText = sql;
+            command.Transaction = transaction;
+
+            int affectedRows = 0;
+
+            foreach (var parameters in parameterSets)
+            {
+                command.Parameters.Clear();
+                command.Parameters.AddRange(parameters);
+                affectedRows += command.ExecuteNonQuery();
+            }
+
+            transaction.Commit();
+            return affectedRows;
+        }
+    }
+}