public void ExpireSubscriber(Subscriber subscriber)
{
if (subscribers.ContainsKey(subscriber.Name))
{
subscribers.Remove(subscriber.Name);
if (!subscriber.LongLived)
{
amazonSqsFacade.DeleteQueue(subscriber.QueueUrl);
}
}
}
/// <summary>
/// Indicates whether the subscriber is subscribed to the topic.
/// </summary>
/// <param name="topic">The topic to publish the message to. The topic represents a channel.</param>
/// <param name="subscriber">The suject used when publishing to the topic.</param>
/// <returns></returns>
public bool IsSubscribed(Topic topic, Subscriber subscriber)
{
Validate.That(topic).IsNotNull();
Validate.That(subscriber).IsNotNull();
if (isDisposed)
{
throw new ObjectDisposedException(MethodBase.GetCurrentMethod().DeclaringType.Name, "instance has been disposed");
}
var key = GetKey(topic, subscriber);
return subscriptions.ContainsKey(key);
}
public Subscriber GetSubscriber(string channelName, string subscriberId, bool longLived)
{
Validate.That(channelName).IsNotNullOrEmpty();
Validate.That(subscriberId).IsNotNullOrEmpty();
var uniqueQueue = GetQueueName(channelName, subscriberId);
if (subscribers.ContainsKey(uniqueQueue))
{
return subscribers[uniqueQueue];
}
var queueUrl = amazonSqsFacade.CreateOrRetrieveQueue(uniqueQueue);
var queueArn = amazonSqsFacade.GetQueueArn(queueUrl);
var subscriber = new Subscriber(uniqueQueue, queueUrl, queueArn, longLived);
subscribers[uniqueQueue] = subscriber;
return subscriber;
}
/// <summary>
/// Subscribe subscriber from topic.
/// </summary>
/// <param name="topic">The topic to be subscribed to.</param>
/// <param name="subscriber">The subscriber to be unsubscribed from the topic.</param>
/// <param name="messageHandler">The delegate for handling the messages.</param>
/// <returns></returns>
public SubscriptionInfo Subscribe(Topic topic, Subscriber subscriber, Action<Message> messageHandler)
{
Validate.That(topic).IsNotNull();
Validate.That(subscriber).IsNotNull();
Validate.That(messageHandler).IsNotNull();
if (isDisposed)
{
throw new ObjectDisposedException(MethodBase.GetCurrentMethod().DeclaringType.Name, "instance has been disposed");
}
var key = GetKey(topic, subscriber);
return subscriptions.AddOrUpdate(key, k => AddSubscription(topic, subscriber, messageHandler), (x,s) => UpdateSubscription(s, messageHandler));
}
private static string GetKey(Topic topic, Subscriber subscriber)
{
return string.Concat(topic.Name, "-", subscriber.Name);
}
private SubscriptionInfo AddSubscription(Topic topic, Subscriber subscriber, Action<Message> messageHandler)
{
var subscriptionInfo = new SubscriptionInfo
{
Topic=topic,
Subscriber=subscriber
};
amazonSqsFacade.SetSqsPolicyForSnsPublish(subscriber.QueueUrl, subscriber.QueueArn, topic.TopicArn);
subscriptionInfo.SubscriptionArn = amazonSnsFacade.SubscribeQueueToTopic(subscriptionInfo.Subscriber.QueueArn, subscriptionInfo.Topic.TopicArn);
if (subscriptionInfo.Subscriber.LongLived)
{
resourceCounter.Increment(subscriptionInfo.Subscriber.Name);
}
subscriptionInfo.CancelToken = queuePoller.Start(subscriptionInfo, messageHandler);
return subscriptionInfo;
}
/// <summary>
/// Unsubscribe subscriber from topic.
/// </summary>
/// <param name="topic">The topic to be unsubscribed from.</param>
/// <param name="subscriber">The subscriber to be unsubscribed from the topic.</param>
/// <returns></returns>
public SubscriptionInfo Unsubscribe(Topic topic, Subscriber subscriber)
{
Validate.That(topic).IsNotNull();
Validate.That(subscriber).IsNotNull();
if (isDisposed)
{
throw new ObjectDisposedException(MethodBase.GetCurrentMethod().DeclaringType.Name, "instance has been disposed");
}
var key = GetKey(topic, subscriber);
SubscriptionInfo subscriptionInfo;
if (subscriptions.TryRemove(key, out subscriptionInfo))
{
subscriptionInfo.CancelToken.Cancel();
if (!subscriber.LongLived || resourceCounter.Decrement(subscriptionInfo.Subscriber.Name) == 0)
{
amazonSnsFacade.UnsubscribeQueueFromTopic(subscriptionInfo.SubscriptionArn);
}
subscriptionInfo.CancelToken = null;
subscriptionInfo.SubscriptionArn = null;
}
return subscriptionInfo;
}
