Pdf Import Rewrite

Pdf Import rewritten to greatly improve QR Code detection, reduce
reliance on iTextSharp and improve thumbnails. Fixes #50

Disco.Services/Expressions/ExpressionCachePreloadTask.cs

@@ -0,0 +1,38 @@
+using Disco.Data.Repository;
+using Disco.Services.Tasks;
+using Quartz;
+using System;
+using System.Linq;
+
+namespace Disco.Services.Expressions
+{
+    public class ExpressionCachePreloadTask : ScheduledTask
+    {
+
+        public override string TaskName { get { return "Expression Cache - Preload Task"; } }
+        public override bool SingleInstanceTask { get { return true; } }
+        public override bool CancelInitiallySupported { get { return false; } }
+        public override bool LogExceptionsOnly { get { return true; } }
+
+        public override void InitalizeScheduledTask(DiscoDataContext Database)
+        {
+            // Run in Background 5 Second after Scheduled (on App Startup)
+            TriggerBuilder triggerBuilder = TriggerBuilder.Create().StartAt(new DateTimeOffset(DateTime.Now).AddSeconds(5));
+
+            this.ScheduleTask(triggerBuilder);
+        }
+
+        protected override void ExecuteTask()
+        {
+            // Cache Document Template Filter Expressions
+            using (DiscoDataContext database = new DiscoDataContext())
+            {
+                foreach (var documentTemplate in database.DocumentTemplates.Where(dt => dt.FilterExpression != null && dt.FilterExpression != string.Empty))
+                {
+                    if (!string.IsNullOrWhiteSpace(documentTemplate.FilterExpression))
+                        documentTemplate.FilterExpressionFromCache();
+                }
+            }
+        }
+    }
+}