// same as previous but should not deliver the message
// because the second subscriber has also the same filter
public async Task Test_DeliverAtLeastOnce_Delayed2()
{
var hub = new MetaPubSub();
bool timeoutException = false;
// first subscriber which will not process the message due to its filter
hub.Subscribe <MyMessage>(OnMyMessageHandler, OnMyMessagePredicate);
// second subscriber which will subscribe after the message has been published
var t = Task.Run(async() =>
{
await Task.Delay(50);
hub.Subscribe <MyMessage>(OnMyMessageHandler2, OnMyMessagePredicate);
await hub.Unsubscribe <MyMessage>(OnMyMessageHandler2);
});
var message = new MyMessage {
LogSeverity = MetaLogErrorSeverity.Info, DeliverAtLeastOnce = true, WaitForSubscriberTimeout = 100
};
try
{
// the message has a timeout and can wait until the second subscriber come
await hub.Publish(message);
}
catch (TimeoutException)
{
timeoutException = true;
}
Assert.IsTrue(timeoutException);
Assert.IsTrue(message.DeliveredCount == 0);
await hub.Unsubscribe <MyMessage>(OnMyMessageHandler);
}
// subscribed twice but delivered only once
public async Task Basic()
{
var hub = new MetaPubSub();
await Task.Run(() =>
{
for (int i = 0; i < 10_000; i++)
{
var subscriber = new MySubscriber();
//await Task.Delay(50);
hub.Subscribe <MyMessage>(subscriber.Handler);
}
});
int totalDeliveryCount1 = 0;
var t1 = Task.Run(async() =>
{
for (int i = 0; i < 1000; i++)
{
var subscriber = new MySubscriber();
hub.Subscribe <MyEvent>(subscriber.Handler);
var message = new MyMessage();
await hub.Publish(message);
totalDeliveryCount1 += message.DeliveredCount;
await hub.Unsubscribe <MyEvent>(subscriber.Handler);
}
});
int totalDeliveryCount2 = 0;
var t2 = Task.Run(async() =>
{
for (int i = 0; i < 1000; i++)
{
var subscriber = new MySubscriber();
hub.Subscribe <MyMessage>(subscriber.Handler);
var message = new MyMessage();
await hub.Publish(message);
totalDeliveryCount2 += message.DeliveredCount;
await hub.Unsubscribe <MyMessage>(subscriber.Handler);
}
});
await Task.WhenAll(t1, t2);
Assert.IsTrue(totalDeliveryCount1 > (10_000 * 1000) && totalDeliveryCount1 < (10_000 * 1000 + 1000));
Assert.IsTrue(totalDeliveryCount2 == 10_000 * 1000 + 1000);
}
// Should deliver if message is filtered at first and DeliverAtLeastOnce = true but Timeout > 0 and
// after the message has published a new subscriber arrived
public async Task Test_DeliverAtLeastOnce_Delayed()
{
var hub = new MetaPubSub();
// first subscriber which will not process the message due to its filter
hub.Subscribe <MyMessage>(OnMyMessageHandler, OnMyMessagePredicate);
// second subscriber which will subscribe after the message has been published
// also with filter, will not process the message
var t = Task.Run(async() =>
{
await Task.Delay(50);
hub.Subscribe <MyMessage>(OnMyMessageHandler2, OnMyMessagePredicate);
});
// third subscriber which will subscribe after the message has been published
var t2 = Task.Run(async() =>
{
await Task.Delay(70);
hub.Subscribe <MyMessage>(OnMyMessageHandler3);
});
var message = new MyMessage {
LogSeverity = MetaLogErrorSeverity.Info, DeliverAtLeastOnce = true, WaitForSubscriberTimeout = 200000
};
// the message has a timeout and can wait until the second subscriber come
await hub.Publish(message);
Assert.IsTrue(message.DeliveredCount == 1);
await hub.Unsubscribe <MyMessage>(OnMyMessageHandler);
//hub.Unsubscribe<MyMessage>(OnMyMessageHandler2);
//hub.Unsubscribe<MyMessage>(OnMyMessageHandler3);
}
// timeout to wait for a subscriber - your message can be queued and wait until someone subscribed and processed it
public async Task DeliverAtLeastOnceDelayedExample()
{
var hub = new MetaPubSub();
// a subscriber that will subscribe after the message has been published
var t = Task.Run(async() =>
{
await Task.Delay(1500);
Console.WriteLine($"Subscribed to MyMessage at {DateTime.Now:HH:mm:ss.fff}");
hub.Subscribe <MyMessage>(OnMyMessage);
});
// the message has the 10 seconds timeout and can wait until the subscriber come
var message = new MyMessage
{
DeliverAtLeastOnce = true, // this must be set to true
WaitForSubscriberTimeout = 10_000
};
Console.WriteLine($"Start publishing and awaiting at {DateTime.Now:HH:mm:ss.fff}");
// this method will wait until the subscriber receives the message or until timeout expired (10 seconds)
await hub.Publish(message);
Console.WriteLine($"End awaiting at {DateTime.Now:HH:mm:ss.fff}");
await hub.Unsubscribe <MyMessage>(OnMyMessage);
}
// at least once delivery check
async Task AtLeastOnceDeliveryExample()
{
var hub = new MetaPubSub();
var message = new MyMessage
{
// if this not set, NoSubscribersException will not be thrown
DeliverAtLeastOnce = true
};
try
{
// publishing a message when no one is subscribed
await hub.Publish(message);
}
catch (NoSubscribersException ex)
{
// no one is listening
Console.WriteLine($"Exception {ex.GetType()}: {ex.Message}");
}
hub.Subscribe <MyMessage>(OnMyMessage);
await hub.Publish(message);
await hub.Unsubscribe <MyMessage>(OnMyMessage);
}
// subscribes on server and receives a message
public async Task SendMessageToClient()
{
var pipeName = Guid.NewGuid().ToString();
var clientConnectedEvent = new ManualResetEventSlim();
var @event = new ManualResetEventSlim();
int recvCount = 0;
Task Handler(MyMessage x)
{
if (++recvCount == 10)
{
@event.Set();
}
return(Task.CompletedTask);
}
// creating remote hub
var t = Task.Run(async() =>
{
var hub = new MetaPubSub();
hub.StartServer(pipeName);
// wait for the subscriber
clientConnectedEvent.Wait(5000);
// publishing a message at the remote hub
for (int i = 0; i < 10; i++)
{
await hub.Publish(new MyMessage());
}
});
// local hub creation
var hub = new MetaPubSub();
await hub.ConnectToServer(pipeName);
await hub.SubscribeOnServer <MyMessage>(Handler);
// delay allowing the server to process the subscription request
await Task.Delay(100);
clientConnectedEvent.Set();
@event.Wait(5000);
// unsubscribing
await hub.Unsubscribe <MyMessage>(Handler);
Assert.IsTrue(@event.IsSet && recvCount == 10);
}
async Task BasicExample()
{
// hub creation
var hub = new MetaPubSub();
// subscribing to MyMessage
hub.Subscribe <MyMessage>(OnMyMessage);
// publishing a message
await hub.Publish(new MyMessage());
// unsubscribing
await hub.Unsubscribe <MyMessage>(OnMyMessage);
}
// exceptions handling - all exceptions raised when a message processing by subscribers can be caught by the publisher as an AggregateException
async Task ExceptionHandlingExample()
{
var hub = new MetaPubSub();
try
{
var message = new MyMessage
{
DeliverAtLeastOnce = true,
};
// publishing a message when no one subscribed - NoSubscribersException
//await hub.Publish(message);
// publishing a message when no one subscribed and Timeout > 0 - TimeoutException
//message.Timeout = 100;
//await hub.Publish(message);
hub.Subscribe <MyMessage>(OnMyMessageHandlerWithException);
// publishing a message
await hub.Publish(message);
}
catch (NoSubscribersException ex)
{
// No one is subscribed to this message and (message.DeliverAtLeastOnce == true and message.Timeout == 0)
Console.WriteLine($"Exception {ex.GetType()}: {ex.Message}");
}
catch (TimeoutException ex)
{
// No one is subscribed to this message and (message.DeliverAtLeastOnce == true and message.Timeout > 0)
Console.WriteLine($"Exception {ex.GetType()}: {ex.Message}");
}
catch (AggregateException ex)
{
// All exceptions raised when a message processing by subscribers
// can be caught by the publisher as an AggregateException.
// If some of the subscribers throw an exception, other subscribers
// continues to process the message.
Console.WriteLine($"Exception {ex.GetType()}: {ex.Message}");
foreach (var innerEx in ex.InnerExceptions)
{
Console.WriteLine($"\tInner Exception {innerEx.GetType()}: {innerEx.Message}");
}
}
await hub.Unsubscribe <MyMessage>(OnMyMessageHandlerWithException);
}
async Task BasicExample()
{
int count = 0;
Task Handler(MyMessage x)
{
count++;
return(Task.CompletedTask);
}
// Creating the server hub.
// The server and the client hubs should be created in separate processes,
// this example is for demo only.
var serverHub = new MetaPubSub();
// Starting the hub as a server named 'Meta'.
serverHub.StartServer("Meta");
// Client hub creation. There are can be several hubs connected to the same server.
var clientHub = new MetaPubSub();
// Connecting to the remote server.
await clientHub.ConnectToServer("Meta");
// Subscribing to MyMessage on the server and locally at the same time.
await clientHub.SubscribeOnServer <MyMessage>(Handler);
// The server publishes a message.
await serverHub.Publish(new MyMessage());
// Client hub publishes a message and it will be received locally without being sent to the server.
await clientHub.Publish(new MyMessage());
// Client hub sends a message to the server where it will be published and sent back.
await clientHub.PublishOnServer(new MyMessage());
// All three messages should be received.
Debug.Assert(count == 3);
// Unsubscribing both on the server-side and locally.
await clientHub.Unsubscribe <MyMessage>(Handler);
}
public async Task Predicate()
{
var hub = new MetaPubSub();
hub.Subscribe <MyMessage>(OnMyMessageHandler, OnMyMessagePredicate);
var message = new MyMessage {
LogSeverity = MetaLogErrorSeverity.Info
};
await hub.Publish(message);
Assert.IsTrue(message.DeliveredCount == 0);
message = new MyMessage {
LogSeverity = MetaLogErrorSeverity.Error
};
await hub.Publish(message);
Assert.IsTrue(message.DeliveredCount == 1);
await hub.Unsubscribe <MyMessage>(OnMyMessageHandler);
}
// scheduling a message - your message can be queued and published after a time delay
public async Task ScheduleExample()
{
var hub = new MetaPubSub();
hub.Subscribe <MyMessage>(OnMyMessage);
var message = new MyMessage
{
DeliverAtLeastOnce = true,
WaitForSubscriberTimeout = 1500
};
// The message will be published after 3 seconds delay and after that, it can wait another 500 ms for a subscriber.
// When using Schedule method there is no way to receive NoSubscriberException or AggregateException.
hub.Schedule(message, millisecondsDelay: 3000);
Console.WriteLine($"Message scheduled at {DateTime.Now:HH:mm:ss.fff}, delay - 3 sec");
// waiting before unsubscribing
await Task.Delay(3500);
await hub.Unsubscribe <MyMessage>(OnMyMessage);
}
// Should get the NoSubscribersException if message is filtered and DeliverAtLeastOnce = true
public async Task Test_DeliverAtLeastOnce_Filtered()
{
var hub = new MetaPubSub();
bool noSubscriberException = false;
hub.Subscribe <MyMessage>(OnMyMessageHandler, OnMyMessagePredicate);
var message = new MyMessage {
LogSeverity = MetaLogErrorSeverity.Info, DeliverAtLeastOnce = true
};
try
{
await hub.Publish(message);
}
catch (NoSubscribersException)
{
noSubscriberException = true;
}
Assert.IsTrue(noSubscriberException);
Assert.IsTrue(message.DeliveredCount == 0);
await hub.Unsubscribe <MyMessage>(OnMyMessageHandler);
}
// subscribed twice but delivered only once
public async Task Basic()
{
var hub = new MetaPubSub();
var message = new MyMessage();
await hub.Publish(message);
Assert.IsTrue(message.DeliveredCount == 0);
hub.Subscribe <MyMessage>(OnMyMessageHandler);
hub.Subscribe <MyMessage>(OnMyMessageHandler);
message = new MyMessage();
await hub.Publish(message);
Assert.IsTrue(message.DeliveredCount == 1);
await hub.Unsubscribe <MyMessage>(OnMyMessageHandler);
message = new MyMessage();
await hub.Publish(message);
Assert.IsTrue(message.DeliveredCount == 0);
}