I downloaded the red5-recorder (http://www.red5-recorder.com/) , which fails to allow me to start recording. After debugging I found that the netconnection, needed to record to a media server, created does not fire a NetStatusEvent event, so essentially it fails silently. I have implemented the connection with the following minimal working example:
trace("make net connection");
nc = new NetConnection();
nc.client = { onBWDone: function():void{ trace("bandwidth check done.") } };
trace("add event listener");
nc.addEventListener(NetStatusEvent.NET_STATUS, function(event:NetStatusEvent) {
trace("handle");
});
trace("connect!");
nc.connect("rtmp://localshost/oflaDemo/test/");
trace("connect done");
The output of this piece of code is:
make net connection
add event listener
connect!
connect done
The actionscript api states that the connect-call always fires such an event:
http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/flash/net/NetConnection.html#includeExamplesSummary
Moreover, the netconnection is not 'connected' (a state of the NetConnection object) 10 seconds after the call. I also took a look at this: NetConnect fails silently in Flash when called from SilverLight But the fix suggested by the author, swapping rtmp and http in the connection uri, do not work. Also, I tested the uri and in fact the exact same code sniplet in a personal project, where it did work. I just can not seem to find why connecting to a media server fails silently in the red5-recorder project.
The awkward part is that if I pass some random string as a conenction uri, still nothing happens (no event, no exception, no crash). Also not setting nc.client becore nc.connect(), which caused exceptions in my experience, did not cause exceptions.
Any suggestions are welcome.
You are setting the address to localshost instead localhost.
nc.connect("rtmp://localshost/oflaDemo/test/");
Correct address:
nc.connect("rtmp://localhost/oflaDemo/test/");
Related
GOAL
The application needs to constantly read from a socket - and when it receives a line that is not empty it needs to do an appropriate action.
Issue
From what I researched you can't do services in Xamarin Forms, since each service is platform dependent. (IOS, Andoird, Windows). So what I am looking for as a way to constantly monitor inputs from a Bluetooth port in this case, simply by calling a already defined function.
Tried
I tried using a Refresh view. But there were issues with that from a code point of view and a visual point of view.
Current Code
This is what I have tried, but unfortuntately it has mixed results. The socket seems to connect when first pairing but then closed if I try to read:
Device.StartTimer(TimeSpan.FromMilliseconds(miliseconds), () =>
{
command.Execute(null);
return true;
});
The code below works fine for me if I use an http URI, but fails for equivalent https alternative. It works fine when built and run on another machine or when I include it in another app.
GetStringAsync throws an exception: “Exception thrown at 0x770B5722 (KernelBase.dll) in .exe: 0x000006F4: A null reference pointer was passed to the stub. occurred”.
ThreadPool::RunAsync(ref new WorkItemHandler([this](IAsyncAction^ action)
{
HttpClient^ client = ref new HttpClient();
auto uri = ref new Uri(L"https://....");
auto t = create_task(client->GetStringAsync(uri));
t.then([](String^ response)
{
// response should be valid.
});
}));
Running netsh winsock reset to reset the network stack seems to fix the issue!
For me, network stack reset didn't help at all, even device reboot didn't help, but your own answer have pointed me in the right direction: it wasn't my code who suddendly went mad, it was Windows. So what actually helped in my case is starting app without debugger (that is, from Start menu) - after that app continues to work fine when started from Visual Studio. It have happened a few times now, and I can confirm that it always helps.
I have a SignalR hub and two clients (Windows and PCL for Android and iOS). Neither of the clients is able to call some methods on the server. This behaviour is quite odd, since the methods look very similar. Moreover, a colleague of mine is able to call methods I cannot call, and vice versa, does not invoke methods that I invoke with no problems.
Here is an example of a method, which works for me and does not work for my colleague:
public override async Task<bool> RefreshArray(User user, int waitMilis)
{
var cts = new CancellationTokenSource();
try
{
cts.CancelAfter(waitMilis);
await Proxy.Invoke("RefreshArray", user);
return true;
}
catch (Exception ex)
{
OnExceptionOccured(ex);
return false;
}
}
And a method which does not work for me, but works for my colleague:
public override async Task<bool> RequestInformation(User user, Product product, int waitMilis)
{
var cts = new CancellationTokenSource();
try
{
cts.CancelAfter(waitMilis);
await Proxy.Invoke("RequestInformation", user, product);
return true;
}
catch (Exception ex)
{
OnExceptionOccured(ex);
return false;
}
}
Yes, me and my colleague have exactly the same code. And no, there are no typos or different arguments. I have tried to get as much data from the client connection as possible, by setting _connection.TraceLevel = TraceLevels.All; However, I did not get any information on the invoked methods, just on the replies from the hub. When calling RefreshArray, I got exactly the data I requested. When calling RequestInformation, the debugger never even hit the breakpoint in the hub method and the _connection.Trace displayed only this: 11:22:45.6169660 - 7bc57897-489b-49a2-8459-3fcdb8fcf974 - SSE: OnMessage(Data: {})
Has anybody solved a similar issue? Is there a solution?
UPDATE 1
I just realized that I have encountered almost the same issue about a year ago (Possible SignalR bug in Xamarin Android). StackOverflow has also pointed me to a question with almost the same issue (SignalR on Xamarin.iOS - randomly not able to call Hub method), just related to iOS and Azure. However, I got the same proble even outside Xamarin, on Windows Phone 8.1 and and Windows 10 Universal App. Moreover, I am running the server just locally, so it is not an issue od Azure. Is it really possible, that a 2 years old bug has no solution?
UPDATE 2
I have just created a simple console application with SignalR.Client. In the console application every method worked just fine. Amazingly, also the Windows 10 Universal Application started to behave as expected - every hub method was invoked correctly. Windows Phone 8.1 also improved its behaviour (all hub methods invoked). However, every now and then the connection tried to reconnect periodically (for no apparent reason), leading to Connection started reconnecting before invocation result was received. error. The Android application still behaved as before.
So I tried to replicate my previous steps and created another console application, but this time with SignalR.Client.Portable library. To my dissapointment, there was no change in the Android application behaviour.
Next week we will start to test our application on iOS, so I really wonder what new oddities will we encounter.
I have managed to solve the problem (at least so it seems). As it turned out, there is some weird stuff going around, when an application receives an answer from SignalR hub. It seems as if the HubProxy was blocked for a certain period of time on Android, while it drops the connection and starts to reconnect periodically on Windows Phone, not waiting for an asnwer from the hub.
The implementation of RefreshArray on the hub was something like this:
public async Task RefreshArray(User user)
{
await Clients.Caller.SendArray(_globalArray);
await Clients.Caller.SendMoreInformation(_additionalInfo);
}
Because the method sent two methods as an answer, the client Proxy got stuck and each platform handled it in its own unexpected way. The reason why some methods were called on my computer and not on colleagues was, simply, because we had different position of breakpoints, which enabled the application to resolve at least some requests and responses.
The ultimate solution was to add some synchronization into the invokation of methods. Now my hub calls only await Clients.Caller.SendArray(_globalArray);. This is then handled on the client with a ArraySent(string[] array) event, which then subsequently invokes the SendMoreInformation() method on the hub.
in my ExtJS 4.1 application I use a websocket connection to remotely insantiate and control ExtJS classes from the server. The client is registered to websocket.onmessage and is waiting for incoming commands.
I defined a simple protocol for that. The server sends a "CREATE classname id". On client side I use Ext.create to instantiate the class. The server then can send commands via the websocket to the object. E.g. "DOSTUFF id". I'm using the dynamic loading mechnism of ExtJS.
In Chrome everything works fine.
The problem with Firefox is, that the second command message (DOSTUFF) is executed BEFORE the object has been created. This leads to an error because the object cannot be found. It seems that the second websocket commandmessage is executed before ExtJS has loaded the file via HTTP-GET.
In my world JavaScript is executed sequentially (I don't use webworkers). I think the call of Ext.create(..) should be executed synchronously with the HTTP-GET in background, shouldn't it?
Here is a "pseudo" trace output of my client application:
ExecuteCommand (Enter): CREATE ("MyClass", "1")
HTTP-GET "MyClass.js"
ExecuteCommand (Enter): DOSTUFF ("1")
ExecuteCommand (Error): DOSTUFF ("1"): Object not found
ExecuteCommand (Enter): CREATE ("MyClass", "1"): OK! Object created!
It makes sense. The GET request is async by default see Firefox doc: https://developer.mozilla.org/en-US/docs/DOM/XMLHttpRequest/Synchronous_and_Asynchronous_Requests
To avoid this issue check for object existence and if need be let the server know to resend in a few seconds, and repeat.
Ok, as mentioned by DmitryB the HTTP-GET works asynchronous. After the XMLHttpRequest is sent, the control is passed to the next websocket.onmessage.
I solved this problem by using Ext.require with a callback function before I call Ext.create.
It looks something like that:
ExecuteCommand: CREATE ("MyClass", "1")
Ext.require("MyClass", function(c) {
ExecuteCommand: DOSTUFF (c);
}
Even though NavigationService.CanGoBack returns True, NavigationService.GoBack() throws me these exceptions :
A first chance exception of type 'System.ArgumentException' occurred in System.Windows.dll
A first chance exception of type 'System.Reflection.TargetInvocationException' occurred in
This happens systematically on two case, while the third works fine :
Crashes if I call NavigationService.GoBack() in OnNavigatedTo()
Crashes If I call NavigationService.GoBack() as a result of WebException thrown in my HTTPWebRequest when Internet is not available [1]
Works fine if Internet is available and I call NavigationService.GoBack() when my HTTPWebRequest got results, parsed them, and displayed them.
My theory is that I can't call GoBack() too soon after navigating from a page to another... My question : How can I programatically go back up the navigation stack when an HTTPWebRequest fails to load ?
Edit : I've decided to do it another way, but I think my problems might be due to navigation animations and the Windows Phone C# Toolkit (I use Feb 2011 edition)
[1] Details of my code on case 2 :
I have a simple HTTPWebRequest. My callback does this, and my app crashes when in Airplane Mode. The line NavigationService.GoBack() is responsible, even though NavigationService.CanGoBack returns true.
try
{
response = request.EndGetResponse(result);
}
catch (WebException)
{
Dispatcher.BeginInvoke(() =>
{
NavigationService.GoBack();
});
}
I tried using Deployment.Current.Dispatcher.BeginInvoke() also.
You could try using WebClient client = new WebClient();, then use client.DownloadStringAsync(new Uri("request_url")); to make your request and subscribe to the client.DownloadStringCompleted event to receive your data when the request is completed. After parsing the data, in the event handler you can then call NavigationService.GoBack(); or go to whichever page you want.
Also, if you try to do something in the OnNavigatedTo event and run into trouble you could try using the OnNavigatingFrom instead (on the previous page ofc), cancel the navigation e.Cancel = true;, do your thing as in make the request and stuff, then get the application frame and navigate to e.Uri (basically continuing the navigation you previously cancelled).
Altho this second might represent a solution as well, I think the first one is better as it does all the work async thus not blocking your UI thread. This is what I generally use in my apps. Hope it helps.