I'm trying to develop watchOS 3 with Xamarin. My watch is communicating with parent application while it's active. When iOS app is killed or in background state, my watch doesn't receive any updated data. I'm sending request from the watch every 10 seconds in order to get updated data. I'm using WCSession for connection. The question is: is it possible to activate parent application from watch extension?
My functions for connectivity:
public void StartSession()
{
if (session != null)
{
session.Delegate = this;
session.ActivateSession();
Console.WriteLine($"Started Watch Connectivity Session on {Device}");
}
}
public override void SessionReachabilityDidChange(WCSession session)
{
Console.WriteLine($"Watch connectivity Reachable:{(session.Reachable ? '✓' : '✗')} from {Device}");
// handle session reachability change
if (session.Reachable)
{
// great! continue on with Interactive Messaging
}
else {
// 😥 prompt the user to unlock their iOS device
}
}
#region Application Context Methods
public void UpdateApplicationContext(Dictionary<string, object> applicationContext)
{
// Application context doesnt need the watch to be reachable, it will be received when opened
if (validSession != null)
{
try
{
var NSValues = applicationContext.Values.Select(x => new NSString(JsonConvert.SerializeObject(x))).ToArray();
var NSKeys = applicationContext.Keys.Select(x => new NSString(x)).ToArray();
var NSApplicationContext = NSDictionary<NSString, NSObject>.FromObjectsAndKeys(NSValues, NSKeys);
NSError error;
var sendSuccessfully = validSession.UpdateApplicationContext(NSApplicationContext, out error);
if (sendSuccessfully)
{
Console.WriteLine($"Sent App Context from {Device} \nPayLoad: {NSApplicationContext.ToString()} \n");
}
else
{
Console.WriteLine($"Error Updating Application Context: {error.LocalizedDescription}");
}
}
catch (Exception ex)
{
Console.WriteLine($"Exception Updating Application Context: {ex.Message}");
}
}
}
public override void DidReceiveApplicationContext(WCSession session, NSDictionary<NSString, NSObject> applicationContext)
{
Console.WriteLine($"Receiving Message on {Device}");
if (ApplicationContextUpdated != null)
{
var keys = applicationContext.Keys.Select(k => k.ToString()).ToArray();
var values = applicationContext.Values.Select(v => JsonConvert.DeserializeObject(v.ToString())).ToArray();
var dictionary = keys.Zip(values, (k, v) => new { Key = k, Value = v })
.ToDictionary(x => x.Key, x => x.Value);
ApplicationContextUpdated(session, dictionary);
}
}
#endregion
I'm using the frameworks "Microsoft.Azure.EventHubs (2.0.0)" and "Microsoft.Azure.EventHubs.Processor (2.0.1)" to read from the azure notification hub. It works by running the app on the iPhone X iOS 11.2 Simulator but if I try to run the app on my iPhone 6s iOS 11.3 device - the app doesn't connect with the eventhub.
This is my code to connect with the eventhub:
public async Task StartReadingFromHub () {
_eventProcessorHost = new EventProcessorHost (
EhEntityPath,
PartitionReceiver.DefaultConsumerGroupName,
EhConnectionString,
StorageConnectionString,
LeaseContainerName);
var options = new EventProcessorOptions () {
MaxBatchSize = 10
};
await _eventProcessorHost.RegisterEventProcessorAsync<SimpleEventProcessor> (options);
}
This is my EventProcessor:
public class SimpleEventProcessor : IEventProcessor {
public Task CloseAsync (PartitionContext context, CloseReason reason) {
return Task.CompletedTask;
}
public Task OpenAsync (PartitionContext context) {
return Task.CompletedTask;
}
public Task ProcessErrorAsync (PartitionContext context, Exception error) {
return Task.CompletedTask;
}
public Task ProcessEventsAsync (PartitionContext context, IEnumerable<EventData> messages) {
foreach (var eventData in messages) {
var data = Encoding.UTF8.GetString (eventData.Body.Array, eventData.Body.Offset, eventData.Body.Count);
var alert = JsonConvert.DeserializeObject<Alert> (data);
HubMessages.receivedMessages.Add (alert);
}
return context.CheckpointAsync ();
}
}
And the OpenAsync Function will never enter.
I have a Spring Integration configuration that utilizes a priority channel. When an item is read from that channel, local resources are checked at that point in time, and if the resources are not available to process the item, I would like to requeue the message so that another machine picks it up. Originally, I wrongly threw an exception thinking that a requeue would occur, but as was answered in my other question this is not going to work since the priority channel executes in another thread than the listener container.
I thought about placing a filter right after the inbound channel adapter, and throwing an exception if resources are not available at that time, but at that instance in time an accurate assessment of resources cannot be made because resource availability at that time does match what will be available when the message is selected based upon priority.
My next thought is to place a filter after the priority channel and before the service activator and direct messages that cannot be handled by current resources to the discard-channel which is defined as an outbound channel adapter that sends the message back to the original queue. Are there pitfalls to this approach?
EDIT 20150917:
Per Gary's advice, I have moved to RabbitMQ 3.5.x in order to take of the built-in priority queues. I now have a problem tracking the number of attempts as it appears my original message is placed back on the queue, rather than my modified message. I have updated the code blocks to reflect the current setup.
EDIT 20150922:
I am updating this post to reflect the final proof of concept code base that I created. I am not a Spring-Integration expert by any means, so please keep that in mind as well as the fact that this test code is not production ready. My original intent was to have messages resubmitted and retried a certain amount of times if a particular exception was thrown. This can be accomplished using the StatefulRetryOperationsInterceptor. But to experiment further, I wanted to be able to set/increment a header on failure and then have something in my flow that could react to that value. That was accomplished by using an extension of the RepublishMessageRecoverer that overrides additionalHeaders(). This object then is used to configure the RetryOperationsInterceptor.
One other minor thing: I wanted to reduce some of the default Spring Integration logging when my signal exception was thrown, so I needed to make sure I named my error channel "errorChannel" in order to replace the Spring Integration default. I also needed to create a custom ErrorHandler which to assign to the ListenerContainer default which logs everything to ERROR level.
Here is my current setup:
Spring Integration 4.2.0.RELEASE
Spring AMQP 1.5.0.RELEASE
RabbitMQ 3.5.x
Configuration
#Autowired
public void setSpringIntegrationConfigHelper (SpringIntegrationHelper springIntegrationConfigHelper) {
this.springIntegrationConfigHelper = springIntegrationConfigHelper;
}
#Bean
public String priorityPOCQueueName() {
return "poc.priority";
}
#Bean
public Queue priorityPOCQueue(RabbitAdmin rabbitAdmin) {
boolean durable = true;
boolean exclusive = false;
boolean autoDelete = false;
//Adding the x-max-priority argument is what signals RabbitMQ that this is a priority queue. Must be Rabbit 3.5.x
Map<String,Object> arguments = new HashMap<String, Object>();
arguments.put("x-max-priority", 5);
Queue queue = new Queue(priorityPOCQueueName(),
durable,
exclusive,
autoDelete,
arguments);
rabbitAdmin.declareQueue(queue);
return queue;
}
#Bean
public Binding priorityPOCQueueBinding(RabbitAdmin rabbitAdmin) {
Binding binding = new Binding(priorityPOCQueueName(),
DestinationType.QUEUE,
"amq.direct",
priorityPOCQueue(rabbitAdmin).getName(),
null);
rabbitAdmin.declareBinding(binding);
return binding;
}
#Bean
public AmqpTemplate priorityPOCMessageTemplate(ConnectionFactory amqpConnectionFactory,
#Qualifier("priorityPOCQueueName") String queueName,
#Qualifier("jsonMessageConverter") MessageConverter messageConverter) {
RabbitTemplate template = new RabbitTemplate(amqpConnectionFactory);
template.setChannelTransacted(false);
template.setExchange("amq.direct");
template.setQueue(queueName);
template.setRoutingKey(queueName);
template.setMessageConverter(messageConverter);
return template;
}
#Autowired
#Qualifier("priorityPOCQueue")
public void setPriorityPOCQueue(Queue priorityPOCQueue) {
this.priorityPOCQueue = priorityPOCQueue;
}
#Bean
public MessageRecoverer miTestMessageRecoverer(final AmqpTemplate priorityPOCMessageTemplate) {
return new MessageRecoverer() {
#Override
public void recover(org.springframework.amqp.core.Message msg, Throwable t) {
StringBuilder sb = new StringBuilder();
sb.append("Firing Test Recoverer: ").append(t.getClass().getName()).append(" Message Count: ")
.append(msg.getMessageProperties().getMessageCount())
.append(" ID: ").append(msg.getMessageProperties().getMessageId())
.append(" DeliveryTag: ").append(msg.getMessageProperties().getDeliveryTag())
.append(" Redilivered: ").append(msg.getMessageProperties().isRedelivered());
logger.debug(sb.toString());
PriorityMessage m = new PriorityMessage(5);
m.setId(randomGenerator.nextLong(10L, 1000000L));
priorityPOCMessageTemplate.convertAndSend(m , new SimulateErrorHeaderPostProcessor(Boolean.FALSE, m.getPriority()));
}
};
}
#Bean
public RepublishMessageRecoverer miRepublishRecoverer(final AmqpTemplate priorityPOCMessageTemplate) {
class MiRecoverer extends RepublishMessageRecoverer {
public MiRecoverer(AmqpTemplate errorTemplate) {
super(errorTemplate);
this.setErrorRoutingKeyPrefix("");
}
#Override
protected Map<? extends String, ? extends Object> additionalHeaders(
org.springframework.amqp.core.Message message, Throwable cause) {
Map<String, Object> map = new HashMap<>();
if (message.getMessageProperties().getHeaders().containsKey("jmattempts") == false) {
map.put("jmattempts", 0);
} else {
Integer count = Integer.valueOf(message.getMessageProperties().getHeaders().get("jmattempts").toString());
map.put("jmattempts", ++count);
}
return map;
}
} ;
return new MiRecoverer(priorityPOCMessageTemplate);
}
#Bean
public StatefulRetryOperationsInterceptor inadequateResourceInterceptor(#Qualifier("priorityPOCMessageTemplate") AmqpTemplate priorityPOCMessageTemplate
, #Qualifier("priorityMessageKeyGenerator") PriorityMessageKeyGenerator priorityMessageKeyGenerator
, #Qualifier("miTestMessageRecoverer") MessageRecoverer messageRecoverer
, #Qualifier("miRepublishRecoverer") RepublishMessageRecoverer miRepublishRecoverer) {
StatefulRetryInterceptorBuilder b = RetryInterceptorBuilder.stateful();
return b.maxAttempts(2)
.backOffOptions(2000L, 1.0D, 4000L)
.messageKeyGenerator(priorityMessageKeyGenerator)
.recoverer(miRepublishRecoverer)
.build();
}
#Bean(name="exec.priorityPOC")
TaskExecutor taskExecutor() {
ThreadPoolTaskExecutor e = new ThreadPoolTaskExecutor();
e.setCorePoolSize(1);
e.setQueueCapacity(1);
return e;
}
/* #Bean(name="poc.priorityChannel")
public MessageChannel pocPriorityChannel() {
PriorityChannel c = new PriorityChannel(new PriorityComparator());
c.setComponentName("poc.priorityChannel");
c.setBeanName("poc.priorityChannel");
return c;
}
*/
#Bean(name="poc.inputChannel")
public MessageChannel pocPriorityChannel() {
DirectChannel c = new DirectChannel();
c.setComponentName("poc.inputChannel");
c.setBeanName("poc.inputChannel");
return c;
}
#Bean(name="poc.inboundChannelAdapter") //make this a unique name
public AmqpInboundChannelAdapter amqpInboundChannelAdapter(#Qualifier("exec.priorityPOC") TaskExecutor taskExecutor
, #Qualifier("errorChannel") MessageChannel pocErrorChannel
, #Qualifier("inadequateResourceInterceptor") StatefulRetryOperationsInterceptor inadequateResourceInterceptor) {
org.aopalliance.aop.Advice[] adviceChain = new org.aopalliance.aop.Advice[]{inadequateResourceInterceptor};
int concurrentConsumers = 1;
AmqpInboundChannelAdapter a = springIntegrationConfigHelper.createInboundChannelAdapter(taskExecutor
, pocPriorityChannel(), new Queue[]{priorityPOCQueue}, concurrentConsumers, adviceChain
, new PocErrorHandler());
a.setErrorChannel(pocErrorChannel);
return a;
}
#Transformer(inputChannel = "poc.inputChannel", outputChannel = "poc.procesPoc")
public Message<PriorityMessage> incrementAttempts(Message<PriorityMessage> msg) {
//I stopped using this in the POC.
return msg;
}
#ServiceActivator(inputChannel="poc.procesPoc")
public void procesPoc(#Header(SimulateErrorHeaderPostProcessor.ERROR_SIMULATE_HEADER_KEY) Boolean simulateError
, #Headers Map<String, Object> headerMap
, PriorityMessage priorityMessage) throws InterruptedException {
if (isFirstMessageReceived == false) {
//Thread.sleep(15000); //Cause a bit of a backup so we can see prioritizing in action.
isFirstMessageReceived = true;
}
Integer retryAttempts = 0;
if (headerMap.containsKey("jmattempts")) {
retryAttempts = Integer.valueOf(headerMap.get("jmattempts").toString());
}
logger.debug("Received message with priority: " + priorityMessage.getPriority() + ", simulateError: " + simulateError + ", Current attempts count is "
+ retryAttempts);
if (simulateError && retryAttempts < PriorityMessage.MAX_MESSAGE_RETRY_COUNT) {
logger.debug(" Simulating an error and re-queue'ng. Current attempt count is " + retryAttempts);
throw new AnalyzerNonAdequateResourceException();
} else if (simulateError && retryAttempts > PriorityMessage.MAX_MESSAGE_RETRY_COUNT) {
logger.debug(" Max attempt count exceeded");
}
}
/**************************************************************************************************
*
* Error Channel
*
**************************************************************************************************/
//Note that we want to override default Spring error channel, so the name of the bean must be errorChannel
#Bean(name="errorChannel")
public MessageChannel pocErrorChannel() {
DirectChannel c = new DirectChannel();
c.setComponentName("errorChannel");
c.setBeanName("errorChannel");
return c;
}
#ServiceActivator(inputChannel="errorChannel")
public void pocHandleError(Message<MessagingException> message) throws Throwable {
MessagingException me = message.getPayload();
logger.error("pocHandleError: error encountered: " + me.getCause().getClass().getName());
SortedMap<String, Object> sorted= new TreeMap<>();
sorted.putAll(me.getFailedMessage().getHeaders());
if (me.getCause() instanceof AnalyzerNonAdequateResourceException) {
logger.debug("Headers: " + sorted.toString());
//Let this message get requeued
throw me.getCause();
}
Message<?> failedMsg = me.getFailedMessage();
Object o = failedMsg.getPayload();
StringBuilder sb = new StringBuilder();
if (o != null) {
sb.append("AnalyzerErrorHandler: Failed Message Type: ")
.append(o.getClass().getCanonicalName()).append(". toString: ").append(o.toString());
logger.error(sb.toString());
}
//The first level sometimes brings back either MessagingHandlingException or
//MessagingTransformationException which may contain a subcause
Exception e = (Exception)me.getCause();
int i = 0;
sb.delete(0, sb.length());
sb.append("AnalyzerErrorHandler nested messages: ");
while (e != null && i++ < 10) {
sb.append(System.lineSeparator()).append(" ")
.append(e.getClass().getCanonicalName()).append(": ")
.append(e.getMessage());
}
if (i > 0) {
logger.error(sb.toString());
}
//Don't want a message to recycle
throw new AmqpRejectAndDontRequeueException(e);
}
/**
* This gets set on the ListenerContainer. The default handler on the listener
* container logs everything with full stack trace. We don't want to do that
* for our known resource exception
*/
public static class PocErrorHandler implements ErrorHandler {
#Override
public void handleError(Throwable t) {
Throwable cause = t.getCause();
if (cause != null) {
while (cause.getCause() != null) {
cause = cause.getCause();
}
} else {
cause = t;
}
if (cause instanceof AnalyzerNonAdequateResourceException) {
logger.info(AnalyzerNonAdequateResourceException.class.getName() + ": not enough resources to process the item.");
return;
}
else {
logger.error("POC Listener Exception", t);
}
}
}
SpringIntegrationHelper
protected ConnectionFactory connectionFactory;
protected MessageConverter messageConverter;
#Autowired
public void setConnectionFactory (ConnectionFactory connectionFactory) {
this.connectionFactory = connectionFactory;
}
#Autowired
public void setMessageConverter(#Qualifier("jsonMessageConverter") MessageConverter messageConverter) {
this.messageConverter = messageConverter;
}
public AmqpInboundChannelAdapter createInboundChannelAdapter(TaskExecutor taskExecutor
, MessageChannel outputChannel, Queue[] queues, int concurrentConsumers
, org.aopalliance.aop.Advice[] adviceChain,
ErrorHandler errorHandler) {
SimpleMessageListenerContainer listenerContainer =
new SimpleMessageListenerContainer(connectionFactory);
//AUTO is default, but setting it anyhow.
listenerContainer.setAcknowledgeMode(AcknowledgeMode.AUTO);
listenerContainer.setAutoStartup(true);
listenerContainer.setConcurrentConsumers(concurrentConsumers);
listenerContainer.setMessageConverter(messageConverter);
listenerContainer.setQueues(queues);
//listenerContainer.setChannelTransacted(false);
listenerContainer.setErrorHandler(errorHandler);
listenerContainer.setPrefetchCount(1);
listenerContainer.setTaskExecutor(taskExecutor);
listenerContainer.setDefaultRequeueRejected(true);
if (adviceChain != null && adviceChain.length > 0) {
listenerContainer.setAdviceChain(adviceChain);
}
AmqpInboundChannelAdapter a = new AmqpInboundChannelAdapter(listenerContainer);
a.setMessageConverter(messageConverter);
a.setAutoStartup(true);
a.setHeaderMapper(MyAmqpHeaderMapper.createPassAllHeaders());
a.setOutputChannel(outputChannel);
return a;
}
It's not clear why you want to use a PriorityChannel in this context; why not use a priority queue in RabbitMQ? That way, you can run your flow on the container thread.
Sending the queue to the back of the queue yourself would work, but there is a risk of message loss.
Im trying to implement windows phone 8.1 notification background task.
it is implemented with one bug!
the toast notification message will appear in the action center more than once. sometimes 9times.
here is my code:
public sealed class my_bg_notifier: IBackgroundTask
{
public async void Run(IBackgroundTaskInstance taskInstance)
{
var deferral = taskInstance.GetDeferral();
bool status = await notificationChecker.check();
if (status)
{
populateNotification(notificationChecker.count);
}
deferral.Complete();
}
}
I tried to debug so I put a breakpoint over the line status.
and I was surprised that it is called more than once and that is why my notification will pop-up more than one time.
and the message that is showed from the debugger breakpoint clearly states that there are multiple threads doing the same job simultaneously.
so i thought to prevent running the method by more than one thread by using a boolean flag as follow:
public sealed class my_bg_notifier: IBackgroundTask
{
private static bool isNotBusy = true;
public async void Run(IBackgroundTaskInstance taskInstance)
{
if (isNotBusy)
{
isNotBusy = false;
var deferral = taskInstance.GetDeferral();
bool status = await notificationChecker.check();
if (status)
{
populateNotification(notificationChecker.count);
}
deferral.Complete();
}
isNotBusy = true;
}
}
but again that didn't work.
my question is :
why would a background task run more than once by multiple thread simultanously.
and How can I block this behavioud? should I use lock keyword?
Okkkkk!!! It was my fault. In my code i registered the background task on each app launch without checking if it is already registered.
So i used code as below to check if my task is registered then no need to register it again.
var taskRegistered = false;
var exampleTaskName = "ExampleBackgroundTask";
foreach (var task in Background.BackgroundTaskRegistration.AllTasks)
{
if (task.Value.Name == exampleTaskName)
{
taskRegistered = true;
break;
}
}
Source: http://msdn.microsoft.com/en-us/library/windows/apps/xaml/hh977055.aspx
Part of my Silverlight application requires data from three service requests. Up until now I've been chaining the requests so as one completes the other starts... until the end of the chain where I do what I need to do with the data.
Now, I know thats not the best method(!). I've been looking at AutoResetEvent (link to MSDN example) to thread and then synchronize the results but cannot seem to get this to work with async service calls.
Does anyone have any reason to doubt this method or should this work? Code samples gratefully received!
Take a look at this example:
Will fire Completed event and print 'done' to Debug Output once both services returned.
Key thing is that waiting for AutoResetEvents happens in background thread.
public partial class MainPage : UserControl
{
public MainPage()
{
InitializeComponent();
Completed += (s, a) => { Debug.WriteLine("done"); };
wrk.DoWork += (s, a) =>
{
Start();
};
wrk.RunWorkerAsync();
}
public event EventHandler Completed;
private void Start()
{
auto1.WaitOne();
auto2.WaitOne();
Completed(this, EventArgs.Empty);
}
public AutoResetEvent auto1 = new AutoResetEvent(false);
public AutoResetEvent auto2 = new AutoResetEvent(false);
BackgroundWorker wrk = new BackgroundWorker();
private void Button_Click(object sender, RoutedEventArgs e)
{
ServiceReference1.Service1Client clien = new SilverlightAsyncTest.ServiceReference1.Service1Client();
clien.DoWorkCompleted += new EventHandler<SilverlightAsyncTest.ServiceReference1.DoWorkCompletedEventArgs>(clien_DoWorkCompleted);
clien.DoWork2Completed += new EventHandler<SilverlightAsyncTest.ServiceReference1.DoWork2CompletedEventArgs>(clien_DoWork2Completed);
clien.DoWorkAsync();
clien.DoWork2Async();
}
void clien_DoWork2Completed(object sender, SilverlightAsyncTest.ServiceReference1.DoWork2CompletedEventArgs e)
{
Debug.WriteLine("2");
auto1.Set();
}
void clien_DoWorkCompleted(object sender, SilverlightAsyncTest.ServiceReference1.DoWorkCompletedEventArgs e)
{
Debug.WriteLine("1");
auto2.Set();
}
}
It could be done using the WaitHandle in the IAsyncResult returned by each async method.
The code is simple. In Silverlight I just do 10 service calls that will add an item to a ListBox. I'll wait until all the service calls end to add another message to the list (this has to run in a different thread to avoid blocking the UI). Also note that adding items to the list have to be done through the Dispatcher since they will modify the UI. There're a bunch of lamdas, but it's easy to follow.
public MainPage()
{
InitializeComponent();
var results = new ObservableCollection<string>();
var asyncResults = new List<IAsyncResult>();
resultsList.ItemsSource = results;
var service = new Service1Client() as Service1;
1.To(10).Do(i=>
asyncResults.Add(service.BeginDoWork(ar =>
Dispatcher.BeginInvoke(() => results.Add(String.Format("Call {0} finished: {1}", i, service.EndDoWork(ar)))),
null))
);
new Thread(()=>
{
asyncResults.ForEach(a => a.AsyncWaitHandle.WaitOne());
Dispatcher.BeginInvoke(() => results.Add("Everything finished"));
}).Start();
}
Just to help with the testing, this is the service
public class Service1
{
private const int maxMilliSecs = 500;
private const int minMillisSecs = 100;
[OperationContract]
public int DoWork()
{
int millisSecsToWait = new Random().Next(maxMilliSecs - minMillisSecs) + minMillisSecs;
Thread.Sleep(millisSecsToWait);
return millisSecsToWait;
}
}