/// <summary>
/// Creates a new subscription for the specified topic.
/// </summary>
/// <typeparam name="T">The type of data the subscription is expected to return.</typeparam>
/// <typeparam name="TPayloadConverter">The type of the converter that can convert from bytes to the type T.</typeparam>
/// <param name="topic">The topic to subscribe to.</param>
/// <param name="qos">The QOS level to subscribe at.</param>
/// <returns>An observable that yields messages when they arrive.</returns>
/// <exception cref="InvalidTopicException">If a topic that does not meet the MQTT topic spec rules is provided.</exception>
private IObservable <MqttReceivedMessage <T> > CreateNewSubscription <T, TPayloadConverter>(string topic, MqttQos qos)
where TPayloadConverter : IPayloadConverter <T>, new()
{
Log.Info(m => m("Creating subscription for topoc {0} @ QOS {1}.", topic, qos));
try {
var subscriptionTopic = new SubscriptionTopic(topic);
// Get an ID that represents the subscription. We will use this same ID for unsubscribe as well.
var msgId = messageIdentifierDispenser.GetNextMessageIdentifier("subscriptions");
// create a new observable that is used to yield messages
// that arrive for the topoc.
var observable = CreateObservableForSubscription(subscriptionTopic, msgId);
var sub = new Subscription {
Topic = subscriptionTopic,
Qos = qos,
MessageIdentifier = msgId,
CreatedTime = DateTime.Now,
Observable = observable,
};
pendingSubscriptions.Add(sub.MessageIdentifier, sub);
// build a subscribe message for the caller and send it off to the broker.
var msg = new MqttSubscribeMessage().WithMessageIdentifier(sub.MessageIdentifier)
.ToTopic(sub.Topic.ToString())
.AtQos(sub.Qos);
connectionHandler.SendMessage(msg);
return(WrapSubscriptionObservable <T, TPayloadConverter>(sub.Observable));
} catch (ArgumentException ex) {
Log.Warn(m => m("Error while processing topoc {0}. topoc structure not valid.", topic), ex);
throw new InvalidTopicException(ex.Message, topic, ex);
}
}
public void MultiWildcardOnlyTopicMatchesAnyRandomTopic() {
var topic = new SubscriptionTopic("#");
Assert.True(topic.Matches(new PublicationTopic("finance/ibm/closingprice")));
}
public void SingleLevelEqualTopicsMatch() {
var topic = new SubscriptionTopic("finance");
Assert.True(topic.Matches(new PublicationTopic("finance")));
}
public void ToStringReturnsSameTopicAsInput() {
const string expectedTopicString = "finance/ibm";
var topic = new SubscriptionTopic(expectedTopicString);
Assert.Equal(expectedTopicString, topic.ToString());
}
public void TopicsDifferingOnlyByCaseDoNotMatch() {
var topic = new SubscriptionTopic("finance");
Assert.False(topic.Matches(new PublicationTopic("Finance")));
}
public void TopicWithMultiWildcardDoesNotMatchTopicWithDifferenceBeforeWildcardLevel() {
var topic = new SubscriptionTopic("finance/#");
Assert.False(topic.Matches(new PublicationTopic("money/ibm")));
}
public void TopicWithSingleWildcardAtEndMatchesAnythingInSameLevel() {
var topic = new SubscriptionTopic("finance/+/closingprice");
Assert.True(topic.Matches(new PublicationTopic("finance/ibm/closingprice")));
}
public void TopicWithSingleWildcardAtEndDoesNotMatchTopicThatGoesDeeper() {
var topic = new SubscriptionTopic("finance/+");
Assert.False(topic.Matches(new PublicationTopic("finance/ibm/closingprice")));
}
public void TopicWithSingleWildcardAtEndMatchesTopicWithEmptyLastFragmentAtThatSpot() {
var topic = new SubscriptionTopic("finance/ibm/+");
Assert.True(topic.Matches(new PublicationTopic("finance/ibm/")));
}
public void SingleLevelNonEqualTopicsDoNotMatch() {
var topic = new SubscriptionTopic("finance");
Assert.False(topic.Matches(new PublicationTopic("money")));
}
public void TopicWithSingleWildcardMatchesTopicEmptyFragmentAtThatPoint() {
var topic = new SubscriptionTopic("finance/+/closingprice");
Assert.True(topic.Matches(new PublicationTopic("finance//closingprice")));
}
public void TopicWithSingleAndMultiWildcardMatchesTopicWithAnyValueAtThoseLevelsAndDeeper() {
var topic = new SubscriptionTopic("finance/+/closingprice/month/#");
Assert.True(topic.Matches(new PublicationTopic("finance/ibm/closingprice/month/october/2014")));
}
public void TopicWithMoreThanOneSingleWildcardAtDifferentLevelsMatchesTopicWithAnyValueAtThoseLevels() {
var topic = new SubscriptionTopic("finance/+/closingprice/month/+");
Assert.True(topic.Matches(new PublicationTopic("finance/ibm/closingprice/month/october")));
}
public void MultiWildcardOnlyTopicMatchesTopicStartingWithSeparator() {
var topic = new SubscriptionTopic("#");
Assert.True(topic.Matches(new PublicationTopic("/finance/ibm/closingprice")));
}
public void TopicWithSingleWildcardAtEndDoesNotMatchTopicThatDoesNotContainAnythingAtSameLevel() {
var topic = new SubscriptionTopic("finance/+");
Assert.False(topic.Matches(new PublicationTopic("finance")));
}
public void TopicWithMultiWildcardAtEndMatchesTopicThatDoesNotMatchSameDepth() {
var topic = new SubscriptionTopic("finance/#");
Assert.True(topic.Matches(new PublicationTopic("finance")));
}
public void MultiLevelNonEqualTopicsDoNotMatch() {
var topic = new SubscriptionTopic("finance/ibm/closingprice");
Assert.False(topic.Matches(new PublicationTopic("some/random/topic")));
}
/// <summary>
/// Creates an observable for a subscription.
/// </summary>
/// <param name="subscriptionTopic">The topic to the obserbable should read messages on.</param>
/// <param name="msgId">The messgeid assigned to the subscription.</param>
/// <returns>An observable that yields a byte array for each message that arrives on a topoc.</returns>
private IObservable <MqttReceivedMessage <byte[]> > CreateObservableForSubscription(SubscriptionTopic subscriptionTopic, short msgId)
{
var observable = Observable.Create <MqttReceivedMessage <byte[]> >(observer => {
Log.Info(m => m("Creating underlying core observable for topoc {0}.", subscriptionTopic));
// Listen for payload messages and when they arrive for our topoc
// publish them onto the observable.
var msgPubObservable
= Observable.FromEventPattern <PublishEventArgs>(h => publishingManager.MessageReceived += h,
h => publishingManager.MessageReceived -= h);
var msgPubSub = msgPubObservable
.Where(ep => subscriptionTopic.Matches(ep.EventArgs.Topic))
.Select(ep => ep.EventArgs)
.Subscribe(eventArgs => {
try {
// we use the messages topic name here so that if the
// matched subscription was a wildcard, we give the
// consumer the actual topic the message was published
// for, not the original wildcard subscription topic.
observer.OnNext(new MqttReceivedMessage <byte[]>(eventArgs.Topic.ToString(),
eventArgs.PublishMessage.Payload.Message.ToArray()));
} catch (Exception ex) {
Log.Error(m => m("Error while publishing message to observer for topic {0}.", eventArgs.Topic.ToString()), ex);
}
});
// Unsubscribe from the topoc on the server,
return(Disposable.Create(() => {
Log.Info(m => m("Last subscriber gone for topic '{0}', unsubscribing on broker.", subscriptionTopic));
// stop processing publish messages for this topoc received by thethe publishing manager.
msgPubSub.Dispose();
// build a unsubscribe message for the caller and send it off to the broker.
var unsubscribeMsg = new MqttUnsubscribeMessage()
.WithMessageIdentifier(messageIdentifierDispenser.GetNextMessageIdentifier("unsubscriptions"))
.WithMessageIdentifier(msgId)
.FromTopic(subscriptionTopic.ToString());
connectionHandler.SendMessage(unsubscribeMsg);
}));
});
// Publish and refcount so we can share the single subscription amongst all
// subscribers and dispose automatically when everyone has disposed their
// subscriptions.
return(observable.Publish()
.RefCount());
}
public void TopicWithMultiWildcardAtEndMatchesTopicWithAnythingAtWildcardLevel() {
var topic = new SubscriptionTopic("finance/#");
Assert.True(topic.Matches(new PublicationTopic("finance/ibm")));
}
