diff --git a/Core/DAL/DataService.cs b/Core/DAL/DataService.cs
index d4b0626..8e6a5cb 100644
--- a/Core/DAL/DataService.cs
+++ b/Core/DAL/DataService.cs
@@ -51,6 +51,23 @@ namespace LeafWeb.Core.DAL
 			return _db.LeafInputs.FirstOrDefault(li => li.Id == id);
 		}
 
+		public LeafOutputFile GetLeafOutput_ChartFile(int leafInputId)
+		{
+			return GetLeafOutput_FilenameLike(leafInputId, LeafOutputFile.Filename_LeafChart);
+		}
+
+		private LeafOutputFile GetLeafOutput_FilenameLike(int leafInputId, string filename)
+		{
+			var leafOutputChartFile =
+				from leafInput in _db.LeafInputs
+				where leafInput.Id == leafInputId
+				from leafOutput in leafInput.OutputFiles
+				where leafOutput.Filename.Contains(filename)
+				select leafOutput;
+
+			return leafOutputChartFile.FirstOrDefault();
+		}
+
 		public LeafInput GetLeafInput(string uniqueToken)
 		{
 			return _db.LeafInputs.FirstOrDefault(li => li.UniqueToken == uniqueToken);
diff --git a/Core/Entities/LeafOutputFile.cs b/Core/Entities/LeafOutputFile.cs
index f2acb5f..c7fe451 100644
--- a/Core/Entities/LeafOutputFile.cs
+++ b/Core/Entities/LeafOutputFile.cs
@@ -3,6 +3,11 @@ namespace LeafWeb.Core.Entities
 {
 	public class LeafOutputFile
 	{
+		// convention for the filename which LeafCharter uses
+		public const string Filename_LeafChart = "leafgascomparison";
+		public const string Filename_ErrorMessage = "errormessage";
+		public const string Filename_WarningMessage = "warningmessage";
+
 		public int Id { get; set; }
 
 		public virtual LeafInput LeafInput { get; set; }
@@ -11,9 +16,8 @@ namespace LeafWeb.Core.Entities
 
 		public byte[] Contents { get; set; }
 
-		// convention for the filename which LeafCharter uses
-		public bool IsLeafChartFile => Filename?.Contains("leafgascomparison") ?? false;
-		public bool IsErrorMessage => Filename?.Contains("errormessage") ?? false;
-		public bool IsWarningMessage => Filename?.Contains("warningmessage") ?? false;
+		public bool IsLeafChartFile => Filename?.Contains(Filename_LeafChart) ?? false;
+		public bool IsErrorMessage => Filename?.Contains(Filename_ErrorMessage) ?? false;
+		public bool IsWarningMessage => Filename?.Contains(Filename_WarningMessage) ?? false;
 	}
 }
diff --git a/Web/Controllers/ChartController.cs b/Web/Controllers/ChartController.cs
index c61d4f1..b9dd42c 100644
--- a/Web/Controllers/ChartController.cs
+++ b/Web/Controllers/ChartController.cs
@@ -21,11 +21,7 @@ namespace LeafWeb.Web.Controllers
 	{
 		public ActionResult Index(int leafInputId)
 		{
-			var leafOutputFile =
-				DataService
-				.GetLeafInput(leafInputId)?
-				.OutputFiles?
-				.FirstOrDefault(f => f.IsLeafChartFile);
+			var leafOutputFile = DataService.GetLeafOutput_ChartFile(leafInputId);
 
 			if (leafOutputFile == null)
 				throw new ArgumentOutOfRangeException(); // TODO: break
@@ -53,13 +49,9 @@ namespace LeafWeb.Web.Controllers
 
 	    public ActionResult ChartCurve(int leafInputId, string curveId)
 	    {
-		    var leafOutputFile = 
-				DataService
-				.GetLeafInput(leafInputId)?
-				.OutputFiles?
-				.FirstOrDefault(f => f.IsLeafChartFile);
+			var leafOutputFile = DataService.GetLeafOutput_ChartFile(leafInputId);
 
-		    if (leafOutputFile == null)
+			if (leafOutputFile == null)
 			    throw new ArgumentOutOfRangeException(); // TODO: break
 
 		    var curveData = GetCurveData(leafOutputFile.Contents, curveId);