ConnectOleDb.cs

using System;
using System.Data.OleDb;
using System.Threading.Tasks;
using Waher.Script.Abstraction.Elements;
using Waher.Script.Data.Model;
using Waher.Script.Model;
using Waher.Script.Objects;
 
namespace Waher.Script.Data.Functions
{
    public class ConnectOleDb : FunctionMultiVariate
    {
        public ConnectOleDb(ScriptNode ConnectionString, int Start, int Length, Expression Expression)
            : base(new ScriptNode[] { ConnectionString }, argumentTypes1Scalar, Start, Length, Expression)
        {
        }
 
        public ConnectOleDb(ScriptNode ConnectionString, ScriptNode UserName, ScriptNode Password, int Start, int Length, Expression Expression)
            : base(new ScriptNode[] { ConnectionString, UserName, Password }, argumentTypes3Scalar, Start, Length, Expression)
        {
        }
 
        public override string FunctionName => nameof(ConnectOleDb);
 
        public override string[] DefaultArgumentNames => new string[] { "ConnectionString", "UserName", "Password" };
 
        public override bool IsAsynchronous => true;
 
        public override IElement Evaluate(IElement[] Arguments, Variables Variables)
        {
            return this.EvaluateAsync(Arguments, Variables).Result;
        }
 
        public override async Task<IElement> EvaluateAsync(IElement[] Arguments, Variables Variables)
        {
            string ConnectionString = Arguments[0].AssociatedObjectValue?.ToString() ?? string.Empty;
            OleDbConnection Connection;
 
            switch (Arguments.Length)
            {
                case 1:
                default:
                    Connection = new OleDbConnection(ConnectionString);
                    break;
 
                case 3:
                    string UserName = Arguments[1].AssociatedObjectValue?.ToString() ?? string.Empty;
                    string Password = Arguments[2].AssociatedObjectValue?.ToString() ?? string.Empty;
 
                    ConnectionString = ConnectionString.Trim();
                    if (!ConnectionString.EndsWith(";"))
                        ConnectionString += ";";
 
                    ConnectionString += "User Id=" + UserName + ";Password=" + Password + ";";
                    Connection = new OleDbConnection(ConnectionString);
                    break;
            }
 
            await Connection.OpenAsync();
 
            return new ObjectValue(new OleDbDatabase(Connection));
        }
    }
}