thecarlo · April 28, 2019 15:33 · Oct 11, 2013
diff --git a/QueueClient.cs b/QueueClient.cs
@@ -0,0 +1,122 @@
+using Amazon;
+using Amazon.SQS;
+using Amazon.SQS.Model;
+using Amazon.SQS.Util;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+
+namespace Sixeyed.Blogging.Aws
+{
+    public class QueueClient
+    {
+        private AmazonSQSClient _sqsClient;
+        public string QueueName { get; private set; }
+        internal string QueueUrl { get; private set; }
+        internal string QueueArn { get; private set; }
+        private Action<Message> _receiveAction;
+        private CancellationTokenSource _cancellationTokenSource = new CancellationTokenSource();
+
+        public QueueClient(string queueName)
+        {
+            _sqsClient = new AmazonSQSClient(RegionEndpoint.EUWest1);
+            QueueName = queueName;
+            Ensure();
+        }
+
+        public void Ensure()
+        {
+            if (!Exists())
+            {
+                var request = new CreateQueueRequest();
+                request.QueueName = QueueName;
+                var response = _sqsClient.CreateQueue(request);
+                QueueUrl = response.QueueUrl;
+            }
+        }
+
+        public bool Exists()
+        {
+            var exists = false;
+            var queues = _sqsClient.ListQueues();
+            var matchString = string.Format("/{0}", QueueName);
+            var matches = queues.QueueUrls.Where(x => x.EndsWith(QueueName));
+            if (matches.Count() == 1)
+            {
+                exists = true;
+                QueueUrl = matches.ElementAt(0);
+            }
+           return exists;
+        }
+
+        public void Unsubscribe()
+        {
+            _cancellationTokenSource.Cancel();
+        }
+
+        private async void Subscribe()
+        {
+            if (!_cancellationTokenSource.IsCancellationRequested)
+            {
+                var request = new ReceiveMessageRequest { MaxNumberOfMessages = 10 };
+                request.QueueUrl = QueueUrl;
+                var result = await _sqsClient.ReceiveMessageAsync(request, _cancellationTokenSource.Token);
+                if (result.Messages.Count > 0)
+                {
+                    foreach (var message in result.Messages)
+                    {
+                        if (_receiveAction != null && message != null)
+                        {
+                            _receiveAction(message);
+                            DeleteMessage(message.ReceiptHandle);
+                        }
+                    }
+                }
+            }
+            if (!_cancellationTokenSource.IsCancellationRequested)
+            {
+                Subscribe();
+            }
+        }
+
+        private DeleteMessageResponse DeleteMessage(string receiptHandle)
+        {
+            var request = new DeleteMessageRequest();
+            request.QueueUrl = QueueUrl;
+            request.ReceiptHandle = receiptHandle;
+            return  _sqsClient.DeleteMessage(request);
+        }
+
+        public void Subscribe(Action<Message> receiveAction)
+        {
+            _receiveAction = receiveAction;
+            _cancellationTokenSource = new CancellationTokenSource();
+            Subscribe();
+        }
+
+        public void Send(Message message)
+        {
+            var request = new SendMessageRequest();
+            request.QueueUrl = QueueUrl;
+            request.MessageBody = message.Body;
+            _sqsClient.SendMessage(request);
+        }
+
+        public bool HasMessages()
+        {
+            var request = new GetQueueAttributesRequest 
+            {
+                 QueueUrl = QueueUrl,
+                 AttributeNames = new List<string>(new string[] { SQSConstants.ATTRIBUTE_APPROXIMATE_NUMBER_OF_MESSAGES})
+            };
+            var response = _sqsClient.GetQueueAttributes(request);
+            return response.ApproximateNumberOfMessages > 0;
+        }
+
+        public bool IsListening()
+        {
+            return !_cancellationTokenSource.IsCancellationRequested;
+        }
+    }
+}