Pdf Import Rewrite

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

Disco.Services/Documents/AttachmentImport/ImportDirectoryMonitor.cs

@@ -0,0 +1,92 @@
+using Quartz;
+using Quartz.Impl;
+using Quartz.Impl.Triggers;
+using System;
+using System.IO;
+
+namespace Disco.Services.Documents.AttachmentImport
+{
+    public class ImportDirectoryMonitor : IDisposable
+    {
+        private FileSystemWatcher watcher;
+
+        public const string WatcherFilter = "*.pdf";
+        public string MonitorLocation { get; private set; }
+        public IScheduler Scheduler { get; private set; }
+        public int ImportDelay { get; private set; }
+
+        public ImportDirectoryMonitor(string MonitorLocation, IScheduler Scheduler, int ImportDelay)
+        {
+            if (MonitorLocation == null)
+                throw new ArgumentNullException(nameof(MonitorLocation));
+            if (Scheduler == null)
+                throw new ArgumentNullException(nameof(Scheduler));
+
+            this.MonitorLocation = MonitorLocation.EndsWith(@"\") ? MonitorLocation : $@"{MonitorLocation}\";
+            this.Scheduler = Scheduler;
+            this.ImportDelay = Math.Max(0, ImportDelay);
+        }
+
+        public void Start()
+        {
+            if (watcher == null)
+            {
+                if (!Directory.Exists(MonitorLocation))
+                {
+                    Directory.CreateDirectory(MonitorLocation);
+                }
+
+                watcher = new FileSystemWatcher(MonitorLocation, WatcherFilter);
+                watcher.Created += OnFileCreated;
+            }
+
+            watcher.EnableRaisingEvents = true;
+        }
+
+        public void Stop()
+        {
+            if (watcher != null)
+            {
+                watcher.EnableRaisingEvents = false;
+            }
+        }
+
+        private void OnFileCreated(object sender, FileSystemEventArgs e)
+        {
+            if (!e.ChangeType.HasFlag(WatcherChangeTypes.Deleted))
+            {
+                ScheduleImport(e.FullPath, ImportDelay);
+            }
+        }
+
+        private void ScheduleImport(string Filename, int ImportDelay)
+        {
+            var startTime = new DateTimeOffset(DateTime.Now.AddMilliseconds(ImportDelay));
+            var jobTrigger = new SimpleTriggerImpl(Guid.NewGuid().ToString(), startTime);
+
+            var jobDetails = new JobDetailImpl(Guid.NewGuid().ToString(), typeof(ImporterJob));
+            jobDetails.JobDataMap.Add("Filename", Filename);
+            jobDetails.JobDataMap.Add("RetryCount", 0);
+
+            Scheduler.ScheduleJob(jobDetails, jobTrigger);
+        }
+
+        public void ScheduleCurrentFiles(int ImportDelay)
+        {
+            foreach (var filename in Directory.GetFiles(this.MonitorLocation, "*.pdf"))
+            {
+                ScheduleImport(filename, ImportDelay);
+            }
+        }
+
+        public void Dispose()
+        {
+            if (watcher != null)
+            {
+                watcher.EnableRaisingEvents = false;
+                watcher.Dispose();
+                watcher = null;
+            }
+        }
+    }
+}