cuipod/Chatter/Connector/SqLiteConnector.cs

using Chatter.Dto;
using System;
using System.Collections.Generic;
using System.Data.SQLite;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Chatter.Connector
{
    public interface IDbConnector: IDisposable
    {
        IEnumerable<MessageDto> GetMessages();

        void AddMessage(MessageDto msg);
    }


    //Not building a context will do it quick and dirty without entity framework
    internal class SqLiteConnector : IDbConnector
    {
        private readonly SQLiteConnectionStringBuilder _connectionStringBuilder;
        private readonly SQLiteConnection _connection;
        private readonly string _addCommand = "INSERT INTO messages(text, createdate, user) VALUES (@text, @createdate, @user);";
        private readonly string _getCommand = "SELECT text, createdate, user FROM messages ORDER BY createdate DESC;";

        private readonly string _createCommand = "CREATE TABLE IF NOT EXISTS messages (id INTEGER PRIMARY KEY AUTOINCREMENT, text TEXT NOT NULL, createdate DATETIME NOT NULL, user varchar);";

        private bool disposedValue;

        public SqLiteConnector()
        {
            _connectionStringBuilder = new SQLiteConnectionStringBuilder() { DataSource = ":memory:", Version = 3 };
            //_connectionStringBuilder = new SQLiteConnectionStringBuilder() { DataSource = "D:\\sql.s3db", Version = 3 };
            _connection = GetDbConnection();
            _connection.Open();
            PrepareTable();
        }

        SQLiteConnection GetDbConnection()
        {
            return new SQLiteConnection(_connectionStringBuilder.ToString());
        }

        private void PrepareTable()
        {
            //_connection.Open();

            using (var cmd = new SQLiteCommand(_createCommand, _connection))
            {
                var data = cmd.ExecuteNonQuery();
            }

            //_connection.Close(); // no async for you today

        }

        public void AddMessage(MessageDto msg)
        {
            //_connection.Open();

            using (var cmd = new SQLiteCommand(_addCommand, _connection))
            {
                var arguments = new Dictionary<string, object>()
                {
                    { "@text", msg.Text ?? string.Empty },
                    { "@createdate", msg.CreateDate },
                    { "@user", msg.User }
                };

                foreach (var pair in arguments)
                {
                    cmd.Parameters.AddWithValue(pair.Key, pair.Value);
                }

                cmd.ExecuteNonQuery();
            }

            //_connection.Close(); // no async for you today
        }

        public IEnumerable<MessageDto> GetMessages()
        {
            var result = new List<MessageDto>();


            using (var cmd = new SQLiteCommand(_getCommand, _connection))
            {
                using (var reader = cmd.ExecuteReader())
                {
                    while(reader.Read())
                    {
                        var text = reader.GetString(0);
                        var createDate = reader.GetString(1);
                        var user = reader.GetValue(2);

                        var message = new MessageDto()
                        {
                            Text = text,
                            CreateDate = DateTime.Parse(createDate),
                            User = user?.ToString()
                        };
                        result.Add(message);
                    }
                }
            }

            //_connection.Close(); // no async for you today

            return result;
        }

        protected virtual void Dispose(bool disposing)
        {
            if (!disposedValue)
            {
                if (disposing)
                {
                    _connection.Close();
                    _connection.Dispose();
                }

                disposedValue = true;
            }
        }

        public void Dispose()
        {
            Dispose(disposing: true);
            GC.SuppressFinalize(this);
        }
    }
}