Changed the approach to let the library create and dispose of the

connection internally. Implemented as a constructor overload on ExcelQueryFactory
paulyoder · Sep 9, 2013 · cc4d4c1 · cc4d4c1
1 parent 0c48302
commit cc4d4c1
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Showing 8 changed files with 123 additions and 114 deletions.
diff --git a/src/LinqToExcel.Tests/ExternalConnection_IntegrationTests.cs b/src/LinqToExcel.Tests/ExternalConnection_IntegrationTests.cs
diff --git a/src/LinqToExcel.Tests/LinqToExcel.Tests.csproj b/src/LinqToExcel.Tests/LinqToExcel.Tests.csproj
@@ -91,6 +91,7 @@
     <Compile Include="ConnectionString_UnitTests.cs" />
     <Compile Include="Excel2007_IntegrationTests.cs" />
     <Compile Include="ExcelQueryFactoryTests.cs" />
+    <Compile Include="PersistentConnection_IntegrationTests.cs" />
     <Compile Include="NoHeader_IntregrationTests.cs" />
     <Compile Include="NoHeader_SQLStatements_UnitTests.cs" />
     <Compile Include="Range_IntegrationTests.cs" />

diff --git a/src/LinqToExcel/ExcelQueryFactory.cs b/src/LinqToExcel/ExcelQueryFactory.cs
@@ -1,5 +1,7 @@
 using System;
 using System.Collections.Generic;
+using System.Data;
+using System.Data.OleDb;
 using System.Linq.Expressions;
 using LinqToExcel.Domain;
 using LinqToExcel.Query;
@@ -10,8 +12,9 @@ public class ExcelQueryFactory : IExcelQueryFactory
     {
         private readonly Dictionary<string, string> _columnMappings = new Dictionary<string, string>();
         private readonly Dictionary<string, Func<string, object>> _transformations = new Dictionary<string, Func<string, object>>();
+		private OleDbConnection _persistentConnection;
 
-        /// <summary>
+	    /// <summary>
         /// Full path to the Excel spreadsheet
         /// </summary>
         public string FileName { get; set; }
@@ -39,6 +42,21 @@ public ExcelQueryFactory(string fileName)
             DatabaseEngine = ExcelUtilities.DefaultDatabaseEngine();
         }
 
+		/// <param name="fileName">Full path to the Excel spreadsheet</param>
+		/// <param name="createPersistentConnection">If <c>true</c>, a connection will be created and shared for the lifetime of the factory. If <c>false</c>, a connection will be created and disposed for each query operation (default)</param>
+		public ExcelQueryFactory(string fileName, bool createPersistentConnection) : this(fileName)
+		{
+			if (createPersistentConnection)
+			{
+				_persistentConnection = new OleDbConnection(ExcelUtilities.GetConnectionString(new ExcelQueryArgs
+				{
+					DatabaseEngine = DatabaseEngine,
+					FileName = fileName,
+					NoHeader = true
+				}));
+			}
+		}
+
         #region Other Methods
 
         /// <summary>
@@ -135,7 +153,8 @@ internal ExcelQueryConstructorArgs GetConstructorArgs()
                 DatabaseEngine = DatabaseEngine,
                 StrictMapping = StrictMapping,
                 ColumnMappings = _columnMappings,
-                Transformations = _transformations
+                Transformations = _transformations,
+				PersistentConnection = _persistentConnection
             };
         }
 
@@ -244,7 +263,8 @@ public ExcelQueryable<Row> WorksheetRange(string startRange, string endRange)
                 new ExcelQueryArgs(GetConstructorArgs())
                 {
                     StartRange = startRange,
-                    EndRange = endRange
+                    EndRange = endRange,
+					PersistentConnection = _persistentConnection
                 });
         }
 
@@ -412,9 +432,28 @@ public ExcelQueryable<RowNoHeader> WorksheetRangeNoHeader(string startRange, str
 
         #endregion
 
-        #region Static Methods
-
-        /// <summary>
+		#region IDisposable Methods
+		public void Dispose()
+		{
+			try
+			{
+				if (_persistentConnection != null)
+				{
+					_persistentConnection.Dispose();
+				}
+			}
+			catch
+			{}
+			finally
+			{
+				_persistentConnection = null;
+			}
+		}
+		#endregion
+
+		#region Static Methods
+
+		/// <summary>
         /// Enables Linq queries against an Excel worksheet
         /// </summary>
         /// <typeparam name="TSheetData">Class type to return row data as</typeparam>
@@ -543,5 +582,5 @@ public static ExcelQueryable<TSheetData> Worksheet<TSheetData>(int worksheetInde
         }
 
         #endregion
-    }
+	}
 }
diff --git a/src/LinqToExcel/IExcelQueryFactory.cs b/src/LinqToExcel/IExcelQueryFactory.cs
@@ -1,12 +1,13 @@
 using System;
+using System.Data.OleDb;
 using System.Linq.Expressions;
 using LinqToExcel.Query;
 using System.Collections.Generic;
 using LinqToExcel.Domain;
 
 namespace LinqToExcel
 {
-    public interface IExcelQueryFactory
+    public interface IExcelQueryFactory : IDisposable
     {
         /// <summary>
         /// Full path to the Excel spreadsheet

diff --git a/src/LinqToExcel/Query/ExcelQueryArgs.cs b/src/LinqToExcel/Query/ExcelQueryArgs.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Data.OleDb;
 using System.Linq;
 using System.Text;
 using LinqToExcel.Domain;
@@ -18,6 +19,7 @@ internal class ExcelQueryArgs
         internal string EndRange { get; set; }
         internal bool NoHeader { get; set; }
         internal StrictMappingType? StrictMapping { get; set; }
+		internal OleDbConnection PersistentConnection { get; set; }
 
         internal ExcelQueryArgs()
             : this(new ExcelQueryConstructorArgs() { DatabaseEngine = ExcelUtilities.DefaultDatabaseEngine() })
@@ -30,6 +32,7 @@ internal ExcelQueryArgs(ExcelQueryConstructorArgs args)
             ColumnMappings = args.ColumnMappings ?? new Dictionary<string, string>();
             Transformations = args.Transformations ?? new Dictionary<string, Func<string, object>>();
             StrictMapping = args.StrictMapping ?? StrictMappingType.None;
+	        PersistentConnection = args.PersistentConnection;
         }
 
         public override string ToString()
@@ -38,9 +41,10 @@ public override string ToString()
             foreach (var kvp in ColumnMappings)
                 columnMappingsString.AppendFormat("[{0} = '{1}'] ", kvp.Key, kvp.Value);
             var transformationsString = string.Join(", ", Transformations.Keys.ToArray());
+	        string persistentConnection = (PersistentConnection == null) ? string.Empty : PersistentConnection.ConnectionString;
 
-            return string.Format("FileName: '{0}'; WorksheetName: '{1}'; WorksheetIndex: {2}; StartRange: {3}; EndRange: {4}; NoHeader: {5}; ColumnMappings: {6}; Transformations: {7}, StrictMapping: {8}",
-                FileName, WorksheetName, WorksheetIndex, StartRange, EndRange, NoHeader, columnMappingsString, transformationsString, StrictMapping);
+            return string.Format("FileName: '{0}'; WorksheetName: '{1}'; WorksheetIndex: {2}; StartRange: {3}; EndRange: {4}; NoHeader: {5}; ColumnMappings: {6}; Transformations: {7}, StrictMapping: {8}; PersistentConnection: {9}",
+                FileName, WorksheetName, WorksheetIndex, StartRange, EndRange, NoHeader, columnMappingsString, transformationsString, StrictMapping, persistentConnection);
         }
     }
 }
diff --git a/src/LinqToExcel/Query/ExcelQueryConstructorArgs.cs b/src/LinqToExcel/Query/ExcelQueryConstructorArgs.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Data.OleDb;
 using System.Linq;
 using System.Text;
 using LinqToExcel.Domain;
@@ -13,5 +14,7 @@ internal class ExcelQueryConstructorArgs
         internal Dictionary<string, string> ColumnMappings { get; set; }
         internal Dictionary<string, Func<string, object>> Transformations { get; set; }
         internal StrictMappingType? StrictMapping { get; set; }
+		internal bool CreatePersistentConnection { get; set; }
+		internal OleDbConnection PersistentConnection { get; set; }
     }
 }
diff --git a/src/LinqToExcel/Query/ExcelQueryExecutor.cs b/src/LinqToExcel/Query/ExcelQueryExecutor.cs
@@ -20,15 +20,19 @@ internal class ExcelQueryExecutor : IQueryExecutor
     {
         private readonly ILog _log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
         private readonly ExcelQueryArgs _args;
-        private readonly string _connectionString;
 
         internal ExcelQueryExecutor(ExcelQueryArgs args)
         {
             ValidateArgs(args);
             _args = args;
-            _connectionString = ExcelUtilities.GetConnectionString(args);
-            if (_log.IsDebugEnabled)
-                _log.DebugFormat("Connection String: {0}", _connectionString);
+
+			string connectionString = args.PersistentConnection != null ? 
+				args.PersistentConnection.ConnectionString : 
+				ExcelUtilities.GetConnectionString(args);
+
+			if (_log.IsDebugEnabled)
+				_log.DebugFormat("Connection String: {0}", connectionString);
+
             GetWorksheetName();
         }
 
@@ -164,11 +168,15 @@ protected IEnumerable<object> GetDataResults(SqlParts sql, QueryModel queryModel
         {
             IEnumerable<object> results;
             OleDbDataReader data = null;
-            using (var conn = new OleDbConnection(_connectionString))
+
+	        var conn = ExcelUtilities.GetConnection(_args);
             using (var command = conn.CreateCommand())
             {
-                conn.Open();
-                command.CommandText = sql.ToString();
+	            if (conn.State != ConnectionState.Open)
+	            {
+		            conn.Open();
+	            }
+	            command.CommandText = sql.ToString();
                 command.Parameters.AddRange(sql.Parameters.ToArray());
                 try { data = command.ExecuteReader(); }
                 catch (OleDbException e)
@@ -192,6 +200,12 @@ protected IEnumerable<object> GetDataResults(SqlParts sql, QueryModel queryModel
                 else
                     results = GetTypeResults(data, columns, queryModel);
             }
+
+			if (_args.PersistentConnection == null)
+			{
+				conn.Dispose();
+			}
+
             return results;
         }
 

diff --git a/src/LinqToExcel/Query/ExcelUtilities.cs b/src/LinqToExcel/Query/ExcelUtilities.cs
@@ -69,33 +69,55 @@ internal static string GetConnectionString(ExcelQueryArgs args)
 
         internal static IEnumerable<string> GetWorksheetNames(string fileName)
         {
-            var args = new ExcelQueryArgs();
-            args.FileName = fileName;
-            return GetWorksheetNames(args);
+	        return GetWorksheetNames(fileName, new ExcelQueryArgs());
         }
 
+		internal static IEnumerable<string> GetWorksheetNames(string fileName, ExcelQueryArgs args)
+		{
+			args.FileName = fileName;
+			return GetWorksheetNames(args);
+		} 
+
+		internal static OleDbConnection GetConnection(ExcelQueryArgs args)
+		{
+			if (args.PersistentConnection != null)
+				return args.PersistentConnection;
+
+			return new OleDbConnection(GetConnectionString(args));
+		}
+
         internal static IEnumerable<string> GetWorksheetNames(ExcelQueryArgs args)
         {
             var worksheetNames = new List<string>();
-            using (var conn = new OleDbConnection(GetConnectionString(args)))
-            {
-                conn.Open();
-                var excelTables = conn.GetOleDbSchemaTable(
-                    OleDbSchemaGuid.Tables,
-                    new Object[] { null, null, null, "TABLE" });
-
-                worksheetNames.AddRange(
-                    from DataRow row in excelTables.Rows
-                    where IsTable(row)
-                    let tableName = row["TABLE_NAME"].ToString()
-                        .Replace("$", "")
-                        .RegexReplace("(^'|'$)", "")
-                        .Replace("''", "'")
-                    where IsNotBuiltinTable(tableName)
-                    select tableName);
-
-                excelTables.Dispose();
-            }
+
+	        var conn = GetConnection(args);
+
+	        if (conn.State != ConnectionState.Open)
+	        {
+		        conn.Open();
+	        }
+
+	        var excelTables = conn.GetOleDbSchemaTable(
+                OleDbSchemaGuid.Tables,
+                new Object[] { null, null, null, "TABLE" });
+
+            worksheetNames.AddRange(
+                from DataRow row in excelTables.Rows
+                where IsTable(row)
+                let tableName = row["TABLE_NAME"].ToString()
+                    .Replace("$", "")
+                    .RegexReplace("(^'|'$)", "")
+                    .Replace("''", "'")
+                where IsNotBuiltinTable(tableName)
+                select tableName);
+
+            excelTables.Dispose();
+
+			if (args.PersistentConnection == null)
+			{
+				conn.Dispose();
+			}
+
             return worksheetNames;
         }