GDAT.DLL - Source [v3.2]

using System;
using System.Collections.Generic;
using System.Data;
using System.Text;
using System.Xml;
using System.Data.SQLite;

namespace GDAT
{
    public class GDATConverter
    {
        public static SQLiteDatabase database = new SQLiteDatabase();
        public GDATConverter(string inputFile = "")
        {
            if (!string.IsNullOrEmpty(inputFile))
                database = new SQLiteDatabase(inputFile);
        }

        private static System.Net.WebClient webClient = new System.Net.WebClient() { Proxy = null };

        public static string UsernameToUserId(string username, bool ThrowException = true)
        {
            string result = null;
            bool erroneous = false;

            result = database.ExecuteScalar("SELECT userid FROM usernames WHERE username = '" + username + "' LIMIT 1");

            if (string.IsNullOrEmpty(result))
            {
                result = webClient.DownloadString(string.Format("http://atil.la/public_projects/gDat/?input={0}&type=false", username));
                if (checkErroneous(result, ThrowException)) { erroneous = true; result = null; }
                else
                {
                    if (!erroneous)
                    {
                        Dictionary<string, string> dict = new Dictionary<string, string>();
                        dict.Add("username", username);
                        dict.Add("userid", result);
                        database.Insert("usernames", dict);
                    }
                }
           }


            return result;
        }
        public static string UserIdToUsername(string userid, bool ThrowException = true)
        {
            string result = null;
            bool erroneous = false;

            result = database.ExecuteScalar("SELECT username FROM usernames WHERE userid = '" + userid + "' LIMIT 1");

            if (string.IsNullOrEmpty(result))
            {
                result = webClient.DownloadString(string.Format("http://atil.la/public_projects/gDat/?input={0}&type=true", userid));
                if (checkErroneous(result, ThrowException)) { erroneous = true; result = null; }
                else
                {
                    if (!erroneous)
                    {
                        Dictionary<string, string> dict = new Dictionary<string, string>();
                        dict.Add("username", result);
                        dict.Add("userid", userid);
                        database.Insert("usernames", dict);
                    }
                }
            }
            return result;
        }
        private static bool checkErroneous(string input, bool ThrowException=true)
        {
            if (input.Contains("Object reference not set to an instance of an object") || input == "^E=1")
            {
                return true;
                if (ThrowException) throw new Exception(string.Format("User does not exist."));
            }
            else if (input.Contains(" is invalid. Keys must be between 1 and 50 word characters (no spaces).") || input == "^E=2")
            {
                return true;
                if (ThrowException) throw new Exception(string.Format("UserId is too long."));
            }
            return false;
        }

        public class SQLiteDatabase
        {
            String dbConnection;

            public SQLiteDatabase()
            {
                dbConnection = "Data Source=gDat.db";
            }
            public SQLiteDatabase(String inputFile)
            {
                dbConnection = String.Format("Data Source={0}", inputFile);
            }
            public SQLiteDatabase(Dictionary<String, String> connectionOpts)
            {
                String str = "";
                foreach (KeyValuePair<String, String> row in connectionOpts)
                {
                    str += String.Format("{0}={1}; ", row.Key, row.Value);
                }
                str = str.Trim().Substring(0, str.Length - 1);
                dbConnection = str;
            }
            public DataTable GetDataTable(string sql)
            {
                DataTable dt = new DataTable();
                try
                {
                    SQLiteConnection cnn = new SQLiteConnection(dbConnection);
                    cnn.Open();
                    SQLiteCommand mycommand = new SQLiteCommand(cnn);
                    mycommand.CommandText = sql;
                    SQLiteDataReader reader = mycommand.ExecuteReader();
                    dt.Load(reader);
                    reader.Close();
                    cnn.Close();
                }
                catch (Exception e)
                {
                    throw new Exception(e.Message);
                }
                return dt;
            }
            public int ExecuteNonQuery(string sql)
            {
                SQLiteConnection cnn = new SQLiteConnection(dbConnection);
                cnn.Open();
                SQLiteCommand mycommand = new SQLiteCommand(cnn);
                mycommand.CommandText = sql;
                int rowsUpdated = mycommand.ExecuteNonQuery();
                cnn.Close();
                return rowsUpdated;
            }
            public string ExecuteScalar(string sql)
            {
                SQLiteConnection cnn = new SQLiteConnection(dbConnection);
                cnn.Open();
                SQLiteCommand mycommand = new SQLiteCommand(cnn);
                mycommand.CommandText = sql;
                object value = mycommand.ExecuteScalar();
                cnn.Close();
                if (value != null)
                {
                    return value.ToString();
                }
                return "";
            }
            public bool Insert(String tableName, Dictionary<String, String> data, bool ThrowException = false)
            {
                String columns = "";
                String values = "";
                Boolean returnCode = true;
                foreach (KeyValuePair<String, String> val in data)
                {
                    columns += String.Format(" {0},", val.Key.ToString());
                    values += String.Format(" '{0}',", val.Value);
                }
                columns = columns.Substring(0, columns.Length - 1);
                values = values.Substring(0, values.Length - 1);
                try
                {
                    this.ExecuteNonQuery(String.Format("insert into {0}({1}) values({2});", tableName, columns, values));
                }
                catch (Exception exception)
                {
                    if (ThrowException)
                        throw exception;
                    returnCode = false;
                }
                return returnCode;
            }
        }
    }
}