I am using Xamarin to develop an Apple Watch app. I am trying to send a message from my watch to the iPhone with my SendMessage function. When I do this, I get in the out error the message payload could not be delivered. I can only read part of the message ("payload could n...") because I am writing it on a label (since my debugger doesn't work in Xamarin I can't take a look at the message), but after doing some googling I'm assuming that's what it is written. Any idea why? Here is my code:
public sealed class WCSessionManager : NSObject, IWCSessionDelegate
{
// Setup is converted from https://www.natashatherobot.com/watchconnectivity-say-hello-to-wcsession/
// with some extra bits
private static readonly WCSessionManager sharedManager = new WCSessionManager();
private static WCSession session = WCSession.IsSupported ? WCSession.DefaultSession : null;
#if __IOS__
public static string Device = "Phone";
#else
public static string Device = "Watch";
#endif
public event ApplicationContextUpdatedHandler ApplicationContextUpdated;
public delegate void ApplicationContextUpdatedHandler(WCSession session, Dictionary<string, object> applicationContext);
public event MessageReceivedHandler MessageReceived;
public delegate void MessageReceivedHandler(Dictionary<string, object> message, Action<Dictionary<string, object>> replyHandler);
private WCSession validSession
{
get
{
#if __IOS__
// Even though session.Paired and session.WatchAppInstalled are underlined, it will still build as they are available on the iOS version of WatchConnectivity.WCSession
Console.WriteLine($"Paired status:{(session.Paired ? '✓' : '✗')}\n");
Console.WriteLine($"Watch App Installed status:{(session.WatchAppInstalled ? '✓' : '✗')}\n");
return (session.Paired && session.WatchAppInstalled) ? session : null;
//return session;
#else
return session;
#endif
}
}
private WCSession validReachableSession
{
get
{
return session.Reachable ? validSession : null;
}
}
private WCSessionManager() : base() { }
public static WCSessionManager SharedManager
{
get
{
return sharedManager;
}
}
public void StartSession()
{
if (session != null)
{
session.Delegate = this;
session.ActivateSession();
Console.WriteLine($"Started Watch Connectivity Session on {Device}");
}
}
[Export("sessionReachabilityDidChange:")]
public void SessionReachabilityDidChange(WCSession session)
{
Console.WriteLine($"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);
UpdateApplicationContextOnSession(NSApplicationContext);
}
catch (Exception ex)
{
Console.WriteLine($"Exception Updating Application Context: {ex.Message}");
}
}
}
public void GetApplicationContext()
{
UpdateApplicationContext(new Dictionary<string, object>() { { "GET", null } });
}
[Export("session:didReceiveApplicationContext:")]
public void DidReceiveApplicationContext(WCSession session, NSDictionary<NSString, NSObject> applicationContext)
{
Console.WriteLine($"Recieving Message on {Device}");
if (ApplicationContextUpdated != null)
{
var keys = applicationContext.Keys.Select(k => k.ToString()).ToArray();
IEnumerable<object> values;
try
{
values = applicationContext.Values.Select(v => JsonConvert.DeserializeObject(v.ToString(), typeof(DoorWatchDTO)));
}
catch (Exception)
{
values = applicationContext.Values.Select(v => JsonConvert.DeserializeObject(v.ToString()));
}
var dictionary = keys.Zip(values, (k, v) => new { Key = k, Value = v })
.ToDictionary(x => x.Key, x => x.Value);
ApplicationContextUpdated(session, dictionary);
}
}
[Export("session:didReceiveMessage::")]
public void DidReceiveMessage(WCSession session, NSDictionary<NSString, NSObject> message, WCSessionReplyHandler replyHandler)
{
if (MessageReceived != null)
{
var keys = message.Keys.Select(k => k.ToString()).ToArray();
IEnumerable<object> values;
values = message.Values.Select(v => JsonConvert.DeserializeObject(v.ToString()));
var dictionary = keys.Zip(values, (k, v) => new { Key = k, Value = v })
.ToDictionary(x => x.Key, x => x.Value);
MessageReceived(dictionary, (dict) =>
{
var NSValues = dict.Values.Select(x => new NSString(JsonConvert.SerializeObject(x))).ToArray();
var NSKeys = dict.Keys.Select(x => new NSString(x)).ToArray();
var NSDict = NSDictionary<NSString, NSObject>.FromObjectsAndKeys(NSValues, NSKeys);
replyHandler.Invoke(NSDict);
});
}
}
public void SendMessage(Dictionary<string, object> message, Action<Dictionary<string, object>> replyHandler, WKInterfaceLabel label)
{
if (validSession != null)
{
try
{
var NSValues = message.Values.Select(x => new NSString(JsonConvert.SerializeObject(x))).ToArray();
var NSKeys = message.Keys.Select(x => new NSString(x)).ToArray();
var NSMessage = NSDictionary<NSString, NSObject>.FromObjectsAndKeys(NSValues, NSKeys);
var reply = new WCSessionReplyHandler((replyMessage) =>
{
var values = replyMessage.Values.Select(x => JsonConvert.SerializeObject(x)).ToArray();
var keys = replyMessage.Keys.Select(x => x.ToString()).ToArray();
var dict = keys.Zip(values, (k, v) => new { Key = k, Value = v })
.ToDictionary(x => x.Key, x => (object)x.Value);
replyHandler.Invoke(dict);
});
validSession.SendMessage(NSMessage, reply, (error) =>
{
label.SetText(error.ToString()); // I can see the error in here: "payload could n..."
});
}
catch (Exception ex)
{
Console.WriteLine($"Exception sending message: {ex.Message}");
}
}
}
private void UpdateApplicationContextOnSession(NSDictionary<NSString, NSObject> NSApplicationContext)
{
NSError error;
var sendSuccessfully = validSession.UpdateApplicationContext(NSApplicationContext, out error);
if (sendSuccessfully)
{
Console.WriteLine($"Sent App Context from {Device} \nPayLoad: {NSApplicationContext.ToString()} \n");
#if __IOS__
Logging.Log("Success, payload: " + NSApplicationContext.ToString());
#endif
}
else
{
Console.WriteLine($"Error Updating Application Context: {error.LocalizedDescription}");
#if __IOS__
Logging.Log("error: " + error.LocalizedDescription);
#endif
}
}
#endregion
I solved it. Instead of implementing IWCSessionDelegate, I simply implement WCSessionDelegate instead and override the functions as needed.
Related
This is a request-response model (like HTTP) but over sockets/websockets. We know which response corresponds to which request by comparing the request IDs.
The workflow is as following:
Subscribe to the observables Error, ContractDetails (_itemObservable) and ContractDetailsEnd (_itemEndObservable)
Match request id to response id and push the corresponding messages via .OnNext(...) to ContractDetails. When there is nothing else left to push, push a final message to ContractDetailsEnd which essentially does .OnCompleted.
Cleanup – unsubscribe, i.e. dispose the observables
In the first snippet below I use a List<TItemArgs>, CancellationTokenSource and a TaskCompletionSource<TItemArgs>. That's completely unnecessary if everything was Rx style. It would have definitely been less lines of code too.
The second snippet is my personal attempt to make it look more Rx like. It has some issues that I want to resolve:
I don't think the try/catch block is necessary since .Subscribe could handle errors
.Timeout didn't work out for me – if the request is not matched within a few seconds, it should return a Result<IEnumerable<TItemArgs>>.FromError(new TimeoutError(...))
In addition to the errors, a message pushed to _errorSubject should also return an error such as Result<IEnumerable<TItemArgs>>.FromError(new RemoteError(...)) but .Merge(errorMessages.Any(_ => false)) is not working.
In my attempt I use ReplaySubject in opposed to AsyncSubject because I believe AsyncSubject is only useful when I'm only interested in the last value of the sequence and want to avoid getting all previous values, which is not in my case. In my case I want to return all values, so ReplaySubject would be more suitable as it keeps track of all the previous values and wants all subscribers to receive the same values, regardless of when they subscribed.
public async ValueTask<Result<IEnumerable<TItemArgs>>> ExecuteAsync(Action<int> action)
{
var requestId = _client.GetNextRequestId();
var data = new List<TItemArgs>();
var cts = new CancellationTokenSource(_timeout);
var tcs = new TaskCompletionSource<IEnumerable<TItemArgs>>();
cts.Token.Register(() =>
{
tcs.TrySetCanceled();
}, false);
void OnError(ErrorData msg)
{
tcs.SetException(new IBClientException(msg.RequestId, msg.Code, msg.Message, msg.AdvancedOrderRejectJson));
}
void OnDetails(TItemArgs item)
{
data.Add(item);
}
void OnDetailsEnd(TItemListEndArgs item)
{
tcs.TrySetResult(data);
}
var disposable = new CompositeDisposable();
_client.Error
.Where(e => HasRequestId && e.RequestId == requestId)
.Subscribe(OnError)
.DisposeWith(disposable);
_itemObservable
.Where(item => MatchRequest(item, _itemRequestIdExtractor, requestId))
.Subscribe(OnDetails)
.DisposeWith(disposable);
_itemEndObservable
.Where(item => MatchRequest(item, _itemListEndRequestIdExtractor, requestId))
.Subscribe(OnDetailsEnd)
.DisposeWith(disposable);
action(requestId);
try
{
await tcs.Task.ContinueWith(x =>
{
disposable.Dispose();
cts.Dispose();
}, TaskContinuationOptions.RunContinuationsAsynchronously);
return Result<IEnumerable<TItemArgs>>.FromSuccess(tcs.Task.Result);
}
catch (Exception e)
{
return Result<IEnumerable<TItemArgs>>.FromError(new RemoteError(e.Message, null));
}
}
My attempt
using System.Reactive.Concurrency;
using System.Reactive.Linq;
using System.Reactive.Subjects;
var client = new IBClient();
var result = await client.GetContractDetailsAsync();
if (result.Success)
{
foreach (var item in result.Data!)
{
Console.WriteLine($"RequestId: {item.RequestId} | Data: {item.ContractDetails}");
}
}
public sealed class IBClient
{
private int _nextValidId;
private readonly Subject<ErrorData> _errorSubject = new();
public IObservable<ErrorData> Error => _errorSubject.AsObservable();
private readonly Subject<ContractDetailsData> _contractDetailsSubject = new();
public IObservable<ContractDetailsData> ContractDetails => _contractDetailsSubject.AsObservable();
private readonly Subject<RequestEndData> _contractDetailsEndSubject = new();
public IObservable<RequestEndData> ContractDetailsEnd => _contractDetailsEndSubject.AsObservable();
public ValueTask<Result<IEnumerable<ContractDetailsData>>> GetContractDetailsAsync()
{
return new PendingRequest<ContractDetailsData, RequestEndData>(
this,
ContractDetails,
ContractDetailsEnd,
e => e.RequestId,
e => e.RequestId)
.ExecuteAsync(reqId => TestCall(reqId));
}
private void TestCall(int requestId)
{
_contractDetailsSubject.OnNext(new ContractDetailsData(requestId, "hey from test call"));
_contractDetailsSubject.OnNext(new ContractDetailsData(requestId, "hey two"));
// TODO: Errors doesn't seem to work
// _errorSubject.OnNext(new ErrorData(requestId, 123, "Error happened", ""));
_contractDetailsEndSubject.OnNext(new RequestEndData(requestId));
// There shouldn't be matched.
_contractDetailsSubject.OnNext(new ContractDetailsData(123, "fake ones, so we know it works"));
_contractDetailsEndSubject.OnNext(new RequestEndData(123));
}
public int GetNextRequestId()
{
return Interlocked.Increment(ref _nextValidId);
}
}
public sealed class PendingRequest<TItemArgs, TItemListEndArgs>
{
private readonly TimeSpan _timeout = TimeSpan.FromSeconds(2);
private readonly IBClient _client;
private readonly IObservable<TItemArgs> _itemObservable;
private readonly IObservable<TItemListEndArgs> _itemEndObservable;
private readonly Func<TItemArgs, int>? _itemRequestIdExtractor;
private readonly Func<TItemListEndArgs, int>? _itemListEndRequestIdExtractor;
public PendingRequest(
IBClient client,
IObservable<TItemArgs> itemObservable,
IObservable<TItemListEndArgs> itemEndObservable,
Func<TItemArgs, int>? itemRequestIdExtractor = null,
Func<TItemListEndArgs, int>? itemListEndRequestIdExtractor = null)
{
_client = client;
_itemObservable = itemObservable;
_itemEndObservable = itemEndObservable;
_itemRequestIdExtractor = itemRequestIdExtractor;
_itemListEndRequestIdExtractor = itemListEndRequestIdExtractor;
}
private bool HasRequestId => _itemRequestIdExtractor != null && _itemListEndRequestIdExtractor != null;
public async ValueTask<Result<IEnumerable<TItemArgs>>> ExecuteAsync(Action<int> action, IScheduler? scheduler = null)
{
scheduler ??= ImmediateScheduler.Instance;
var requestId = _client.GetNextRequestId();
var results = new ReplaySubject<TItemArgs>();
try
{
var errorMessages = _client.Error
.Where(e => HasRequestId && e.RequestId == requestId);
using (_itemObservable
.Where(item => MatchRequest(item, _itemRequestIdExtractor, requestId))
.ObserveOn(scheduler)
.Subscribe(results))
using (_itemEndObservable
.Any(item => MatchRequest(item, _itemListEndRequestIdExtractor, requestId))
.Merge(errorMessages.Any(_ => false)) // TODO: ???
.ObserveOn(scheduler)
.Subscribe(_ => results.OnCompleted()))
{
action(requestId);
// Don't want an Exception thrown if there result list is empty
await results.DefaultIfEmpty();
return Result<IEnumerable<TItemArgs>>.FromSuccess(results.ToEnumerable());
}
}
catch (Exception ex)
{
return Result<IEnumerable<TItemArgs>>.FromError(new RemoteError(ex.Message, null));
}
}
private bool MatchRequest<T>(T item, Func<T, int>? idExtractor, int id)
{
return !HasRequestId || (idExtractor != null && idExtractor(item) == id);
}
}
public sealed class ContractDetailsData
{
public ContractDetailsData(int requestId, string contractDetails)
{
RequestId = requestId;
ContractDetails = contractDetails;
}
public int RequestId { get; }
public string ContractDetails { get; }
}
public sealed class ErrorData
{
public ErrorData(int requestId, int code, string message, string advancedOrderRejectJson)
{
RequestId = requestId;
Code = code;
Message = message;
AdvancedOrderRejectJson = advancedOrderRejectJson;
}
public int RequestId { get; }
public int Code { get; }
public string Message { get; }
public string AdvancedOrderRejectJson { get; }
}
public sealed class RequestEndData
{
public RequestEndData(int requestId)
{
RequestId = requestId;
}
public int RequestId { get; }
}
public class IBClientException : Exception
{
public IBClientException(int requestId, int errorCode, string message, string advancedOrderRejectJson)
: base(message)
{
RequestId = requestId;
ErrorCode = errorCode;
AdvancedOrderRejectJson = advancedOrderRejectJson;
}
public IBClientException(string err)
: base(err)
{
}
public IBClientException(Exception e)
{
Exception = e;
}
public int RequestId { get; }
public int ErrorCode { get; }
public string? AdvancedOrderRejectJson { get; }
public Exception? Exception { get; }
}
public abstract record Error(int? Code, string Message, object? Data);
public record RemoteError : Error
{
public RemoteError(string message, object? data) : base(null, message, data)
{
}
public RemoteError(int? code, string message, object? data) : base(code, message, data)
{
}
}
public record Result<T>(bool Success, T? Data, Error? Error)
{
public Result(T data) : this(true, data, default)
{
}
public Result(Error error) : this(false, default, error)
{
}
public static Result<T> FromSuccess(T data)
{
return new Result<T>(data);
}
public static Result<T> FromError<TError>(TError error) where TError : Error
{
return new Result<T>(error);
}
}
public static class DisposableExtensions
{
public static T DisposeWith<T>(this T disposable, ICollection<IDisposable> collection)
where T : IDisposable
{
ArgumentNullException.ThrowIfNull(disposable);
ArgumentNullException.ThrowIfNull(collection);
collection.Add(disposable);
return disposable;
}
}
Here's a good start:
IObservable<TItemArgs> observable =
Observable
.Merge(
_itemObservable
.Where(item => MatchRequest(item, _itemRequestIdExtractor, requestId))
.Select(item => Notification.CreateOnNext(item))
.Take(1),
_itemEndObservable
.Any(item => MatchRequest(item, _itemListEndRequestIdExtractor, requestId))
.Select(item => Notification.CreateOnCompleted<TItemArgs>()))
.Dematerialize();
And here's a final observable without the ReplaySubject.
private static async Task<Result<IEnumerable<Details>>> Test(IScheduler scheduler) =>
await
Observable
.Defer(() =>
{
var client = new IBClient();
var requestId = 1;
return Observable.Create<Result<IEnumerable<Details>>>(o =>
{
IDisposable subscription =
Observable
.Merge(
client.Details.Where(x => x.RequestId == requestId).Select(x => Notification.CreateOnNext(x)),
client.DetailsEnd.Any(x => x.RequestId == requestId).Select(x => Notification.CreateOnCompleted<Details>()),
client.Error.Where(x => x.RequestId == requestId).Select(x => Notification.CreateOnError<Details>(new Exception($"Code: {x.Code}, Message: {x.Message}"))))
.Dematerialize()
.Synchronize()
.ToArray()
.Select(items => Result<IEnumerable<Details>>.FromSuccess(items))
.Catch<Result<IEnumerable<Details>>, Exception>(ex => Observable.Return(Result<IEnumerable<Details>>.FromError(new Error(null, ex.Message, null))))
.Timeout(TimeSpan.FromSeconds(2))
.ObserveOn(scheduler)
.Subscribe(o);
client.Emit(2, 4);
client.Emit(requestId, 42);
client.EmitEnd(2);
client.Emit(requestId, 62);
client.Emit(requestId, 123);
//client.EmitError(requestId, 123, "Something bad happened");
client.EmitEnd(requestId);
client.Emit(requestId, 1);
return subscription;
});
});
Using Stateless library for .NET I wrote a state machine that does a few things:
Read a barcode ticket
do some validation
check for some more validation
do some digital I/O(turn a light green and open a gate)
frame a transaction and commit it
My StateMachine code is as follows:
public class MainStateMachine
{
public delegate void tvOnTransitioned(StateMachine<State, Trigger>.Transition otransition);
public delegate void tvUnhandledTrigger(State estate, Trigger etrigger);
public delegate void tvEntryExit();
public delegate bool bnGuardClause();
public delegate void vLogMsg(string sstring);
public delegate void tvOnTransition_Barcode(sbarcodeserial);
StateMachine<State, Trigger>.TriggerWithParameters<string> oBarcode_Trigger_With_Parameters;
public tvOnTransitioned OnTransitioned = null;
public tvUnhandledTrigger OnUnhandledTrigger = null;
#region SuperState
public tvEntryExit OnEntry_Input = null;
public tvEntryExit OnExit_Input = null;
#endregion
#region Substates_Entry_Exit
public tvEntryExit OnEntry_CSC_BarcodeValidation = null;
public tvEntryExit OnEntry_PaymentSatisfied = null;
public tvEntryExit OnEntry_FrameTransaction = null;
#endregion
#region Transitions
public tvEntryExit OnTransition_BarcodeValid = null;
public tvEntryExit OnTransition_OCR_Validation_OK = null;
public tvEntryExit OnTransition_LD_RisingEdge = null;
public tvEntryExit OnTransition_BarcodeError = null;
public tvEntryExit OnTransition_BarcodeInvalid = null;
public tvEntryExit OnTransition_OCR_ValidationNot_OK = null;
#endregion
public tvOnTransition_Barcode OnTransition_DO_CSCBarcodeValidation = null;
public enum State
{
//Super states
Input,
//sub states
CSC_Barcode_Validation, OCR_BarcodeValidation, PaymentSatisfied, Transaction
}
public enum Trigger
{
OpenLane,
Trg_CloseLane,
Trg_BC,
Trg_BarCodeRead,
Trg_BarcodeError,
Trg_BarcodeInvalid,
Trg_BarcodeValid,
Trg_OCR_ValidationNot_OK,
Trg_OCR_Validation_OK,
Trg_LDRisingEdge,
Trg_LDFallingEdge
}
State _state = State.Input;
StateMachine<State, Trigger> _sMachine;
object oLock;
public MainStateMachine()
{
this.oLock = new object();
_sMachine = new StateMachine<State, Trigger>(() => _state, s => _state = s);
this._sMachine.OnTransitioned((otransition) => { if (this.OnTransitioned != null) this.OnTransitioned(otransition); });
this._sMachine.OnUnhandledTrigger((estate, etrigger) => { if (this.OnUnhandledTrigger != null) this.OnUnhandledTrigger(estate, etrigger); });
this.oBarcode_Trigger_With_Parameters = this._sMachine.SetTriggerParameters<string>(Trigger.Trg_BC);
//Tag/Barcode Input state
_sMachine.Configure(State.Input)
.Permit(Trigger.Trg_BC, State.CSC_Barcode_Validation)
.OnEntry(() => { if (this.OnEntry_Input != null) this.OnEntry_Input(); })
.OnExit(() => { if (this.OnExit_Input != null) this.OnExit_Input(); });
_sMachine.Configure(State.CSC_Barcode_Validation)
.SubstateOf(State.Input)
.OnEntryFrom(this.oBarcode_Trigger_With_Parameters, (sbarcodeserial) => { if (this.OnTransition_DO_CSCBarcodeValidation != null) this.OnTransition_DO_CSCBarcodeValidation( sbarcodeserial); })
.Permit(Trigger.Trg_BarcodeError, State.Transaction)
.Permit(Trigger.Trg_BarcodeValid, State.OCR_BarcodeValidation)
.OnEntry(() => { if (OnEntry_CSC_BarcodeValidation != null) OnEntry_CSC_BarcodeValidation(); });
_sMachine.Configure(State.OCR_BarcodeValidation)
.SubstateOf(State.Input)
.OnEntryFrom(Trigger.Trg_BarcodeValid, () =>
{
if(this.OnTransition_BarcodeValid != null) this.OnTransition_BarcodeValid();
})
.Permit(Trigger.Trg_OCR_ValidationNot_OK, State.Transaction)
.Permit(Trigger.Trg_OCR_Validation_OK, State.PaymentSatisfied);
_sMachine.Configure(State.PaymentSatisfied)
.Permit(Trigger.Trg_LDRisingEdge, State.Transaction)
.OnEntryFrom(Trigger.Trg_OCR_Validation_OK, () =>
{
if (this.OnTransition_OCR_Validation_OK != null) this.OnTransition_OCR_Validation_OK();
})
.OnEntry(() => { if (this.OnEntry_PaymentSatisfied != null) OnEntry_PaymentSatisfied(); }); //.OnExit(() => { if (this.OnExit_PaymentSatisfied != null) OnExit_PaymentSatisfied(); });
_sMachine.Configure(State.Transaction)
.OnEntryFrom(Trigger.Trg_LDRisingEdge, () =>
{
if (this.OnTransition_LD_RisingEdge != null) this.OnTransition_LD_RisingEdge();
})
.OnEntryFrom(Trigger.Trg_BarcodeError, () => { if (this.OnTransition_BarcodeError != null) this.OnTransition_BarcodeError(); })
.OnEntryFrom(Trigger.Trg_BarcodeInvalid, () => { if (this.OnTransition_BarcodeInvalid != null) this.OnTransition_BarcodeInvalid(); })
.OnEntryFrom(Trigger.Trg_OCR_ValidationNot_OK, () => { if (this.OnTransition_OCR_ValidationNot_OK != null) this.OnTransition_OCR_ValidationNot_OK(); })
.OnEntry(() => { if (this.OnEntry_FrameTransaction != null) OnEntry_FrameTransaction(); }); // on entry into this State, I have to frame a Transaction and commit it
}
public bool TryFireTrigger(Trigger etrigger)
{
bool bReturn = false;
lock (this.oLock)
{
if (this._sMachine.CanFire(etrigger))
{
try
{
this._sMachine.Fire(etrigger);
bReturn = true;
}
catch (Exception oException)
{
bReturn = false;
Console.WriteLine(oException.StackTrace);
}
}
}
return bReturn;
}
}
This State machine is for a vehicle when it enters an unattended booth in a parking lot. I can't figure out as to how to create a transaction object, because it's properties change as and how it undergoes a state change.
Do I pass the Transaction object to each state and get it's modified state back and pass it to next state? I'm not sure how to go about it. Any help is appreciated.
Edit: Another question. What is a substate?
Substates inherit the allowed transitions of their superstate. When entering directly into a substate from outside of the superstate, entry actions for the superstate are executed. Likewise when leaving from the substate to outside the superstate, exit actions for the superstate will execute.
I am using #aspnet/signalr to connect to a hub and from the hub i am calling the method to return me some data.
When i first initialize the server the connection is established normally, but if i refresh the window 3 or 4 times the client stop sending connection request to the server.
I tried logging the HubConnection, the connectionState at first is equal to 1 but after the problem accrues the connectionState is alwase equal 0
Here is how i am building the hubConnection:
buildConnection() {
this.hubConnection = new HubConnectionBuilder()
.withUrl(this.tradesService.getStockQuotationsHubUrl())
.build();
this.hubConnection.serverTimeoutInMilliseconds = 1000 * 10;
this.hubConnection.onclose(() => setTimeout(() => this.startSignalRConnection(), 2000));}
Here is how i am starting the hubConnection:
startConnection() {
this.hubConnection
.start()
.then(() => {
this.hubConnection.on('updateMethod', (data: any) => {
this.store.push([
{ type: 'update', key: data.stockID, data },
]);
});
this.dataSource = new DataSource({
store: this.store,
reshapeOnPush: true,
});
});}
Note: I am listing to 5 hubs at once in my page but the only one having problems is this one.
[Update]
The problem is from the server because when i restart the server the connection is reestablished between the client and the server, but if the client refresh or quit the page for multiple times the hub does not even try to connect to the client
public class StockQuotationsHub : Microsoft.AspNetCore.SignalR.Hub
{
private string SectorID { get; set; }
private int TradingSession { get; set; }
private int MarketID { get; set; }
public static StockQuotationExt stockQuotationExt { get; set; }
private readonly StockQuotationTicker _stockTicker;
public StockQuotationsHub(StockQuotationTicker stockTicker){
_stockTicker = stockTicker;
}
public override Task OnConnectedAsync(){
return base.OnConnectedAsync();
}
public IEnumerable<StockQuotation> GetAllStockQuotations(string[] stockID, string sectorID, int tradingSession, int marketType){
return _stockTicker.
GetAllStocks(Context.ConnectionId, stockID, sectorID, tradingSession, marketType);
}
public override async Task OnDisconnectedAsync(Exception exception){
await base.OnDisconnectedAsync(exception);
}
and here is my stock ticker class:
public IEnumerable<StockQuotation> GetAllStocks(string connectionId, string[] stockID, string sectorID, int tradingSession, int marketType)
{
_stocks = new List<StockQuotation>();
_stocks = Task.Run(async () => await GetStockQuotationModelAsync("", 0, 1, 0)).Result.ToList();
this.MaxTimeStamp = _stocks.Max(s => s.TStamp);
this.SectorID = sectorID;
this.TradingSession = tradingSession;
this.MarketID = marketType;
AddToGroups(connectionId, stockID);
if (_timer==null)
_timer = new Timer(UpdateStockPrices, null, _updateInterval, _updateInterval);
if (stockID.Length == 0)
{
return _stocks;
}
else
{
var stocksList = new List<StockQuotation>();
foreach (var stock in stockID)
{
stocksList.AddRange(_stocks.Where(s => s.StockID == stock).ToList());
}
return stocksList;
}
}
private void AddToGroups(string connectionId, string[] stockID)
{
if (_stocks.Count > 0)
{
if (stockID.Length == 0)
{
Hub.Groups.AddToGroupAsync(connectionId, "ALL");
}
else
{
foreach (var stock in stockID)
{
Hub.Groups.AddToGroupAsync(connectionId, stock);
var s = _stocks.FirstOrDefault(s => s.StockID == stock);
if(s != null)
{
s.Snapshots = new List<double>(GetStockQuotationSnapshots(stock));
}
}
}
}
}
private void AddToGroups(string connectionId, string[] stockID)
{
if (_stocks.Count > 0)
{
if (stockID.Length == 0)
{
Hub.Groups.AddToGroupAsync(connectionId, "ALL");
}
else
{
foreach (var stock in stockID)
{
Hub.Groups.AddToGroupAsync(connectionId, stock);
var s = _stocks.FirstOrDefault(s => s.StockID == stock);
if(s != null)
{
s.Snapshots = new List<double>(GetStockQuotationSnapshots(stock));
}
}
}
}
}
I really appreciated the help.
Eventually the problem was that the project type was MVC, so I changed it to be webApi
and everything worked successfully
Even if you fix it I would like to recommend you to add the following code in order to know exactly the root cause of disconnection.
First of all enable the extended debug info in the service configuration:
services.AddSignalR(o =>
{
o.EnableDetailedErrors = true;
});
Furthermore, you need to attach to the event Closed in HubConnection like that:
hubConnection.Closed += (exception) =>
{
if (exception == null)
{
Console.WriteLine("Connection closed without error.");
}
else
{
Console.WriteLine($"Connection closed due to an error: {exception}");
}
return null;
};
I created a method for check that in db has a stored procedure.
public class StoredProcedure : IStoredProcedure
{
private readonly IDbContextProvider<MyDbContext> _dbContextProvider;
public StoredProcedure(IDbContextProvider<MyDbContext> dbContextProvider)
{
_dbContextProvider = dbContextProvider;
}
public bool ExistsStoredProcedure(string procedureName)
{
var query = string.Format(
"SELECT COUNT(*) FROM [sys].[objects] WHERE [type_desc] = 'SQL_STORED_PROCEDURE' AND [name] = '{0}';",
procedureName);
var request = _dbContextProvider.DbContext.Database.SqlQuery<int>(query).Single();
return request > 0 ? true : throw new UserFriendlyException(
$"Хранимая процедура {procedureName} не найдена в БД {_dbContextProvider.DbContext.Database.Connection.Database}");
}
}
Also, I want to write a unit test for him.
public class StoredProcedureTests
{
private readonly IStoredProcedure _storedProcedure;
private readonly Mock<IDbContextProvider<MyDbContext>> _mockDbProvider;
public StoredProcedureTests()
{
_mockDbProvider = new Mock<IDbContextProvider<MyDbContext>>();
_storedProcedure = new StoredProcedure(_mockDbProvider.Object);
}
[Fact]
public void CheckValueIfStoredProcedureExist()
{
const int count = 1;
var rawMock = new Mock<DbRawSqlQuery<int>>();
rawMock.Setup(i => i.Single()).Returns(count);
_mockDbProvider.Setup(i => i.DbContext.Database.SqlQuery<int>(It.IsAny<string>())).Returns(rawMock.Object);
var result = _storedProcedure.ExistsStoredProcedure(string.Empty);
Assert.True(result);
}
}
But, i get an error, when i try rawMock.Setup
try
{
rawMock.Setup(i => i.Single()).Returns(count);
}
catch (Exception e)
{
Console.WriteLine(e.Message);
throw;
}
Invalid setup on an extension method: i => i.Single()
How to correctly write this stub?
UPD I try like advised Johnny
try
{
IEnumerable<int> list = new List<int> {1};
var mq = new Mock<DbRawSqlQuery<int>>();
mq.Setup(i => i.GetEnumerator()).Returns(list.GetEnumerator);
_mockDbProvider.Setup(i => i.DbContext.Database.SqlQuery<int>(It.IsAny<string>())).Returns(mq.Object);
}
catch (Exception e)
{
Console.WriteLine(e.Message);
throw;
}
And i have a new error
Invalid setup on a non-virtual (overridable in VB) member: i => i.DbContext.Database.SqlQuery(It.IsAny(), new[] { })
I am trying to implement a simple example/demo for a state machine using Automatonymous with RabbitMQ. Unfortunately I could not find one to rebuild / learn from (I found the ShoppingWeb, but in my eyes it's anything but simple). Also in my opinion the documentation is lacking information.
This is the state machine example I thought of (sorry, it's pretty ugly):
Please note that this example is completely made up and it's not important if it makes sense or not. This project's purpose is to get "warm" with Automatonymous.
What I want to do / to have is:
Four applications running:
The state machine itself
The "requester" sending requests to be interpreted
The "validator" or "parser" checking if the provided request is valid
The "interpreter" interpreting the given request
An example of this could be:
Requester sends "x=5"
Validator checks if a "=" is contained
Intepreter says "5"
My implementation of the state machine looks like this:
public class InterpreterStateMachine : MassTransitStateMachine<InterpreterInstance>
{
public InterpreterStateMachine()
{
InstanceState(x => x.CurrentState);
Event(() => Requesting, x => x.CorrelateBy(request => request.Request.RequestString, context => context.Message.Request.RequestString)
.SelectId(context => Guid.NewGuid()));
Event(() => Validating, x => x.CorrelateBy(request => request.Request.RequestString, context => context.Message.Request.RequestString));
Event(() => Interpreting, x => x.CorrelateBy(request => request.Request.RequestString, context => context.Message.Request.RequestString));
Initially(
When(Requesting)
.Then(context =>
{
context.Instance.Request = new Request(context.Data.Request.RequestString);
})
.ThenAsync(context => Console.Out.WriteLineAsync($"Request received: {context.Data.Request.RequestString}"))
.Publish(context => new ValidationNeededEvent(context.Instance))
.TransitionTo(Requested)
);
During(Requested,
When(Validating)
.Then(context =>
{
context.Instance.Request.IsValid = context.Data.Request.IsValid;
if (!context.Data.Request.IsValid)
{
this.TransitionToState(context.Instance, Error);
}
else
{
this.TransitionToState(context.Instance, RequestValid);
}
})
.ThenAsync(context => Console.Out.WriteLineAsync($"Request '{context.Data.Request.RequestString}' validated with {context.Instance.Request.IsValid}"))
.Publish(context => new InterpretationNeededEvent(context.Instance))
,
Ignore(Requesting),
Ignore(Interpreting)
);
During(RequestValid,
When(Interpreting)
.Then((context) =>
{
//do something
})
.ThenAsync(context => Console.Out.WriteLineAsync($"Request '{context.Data.Request.RequestString}' interpreted with {context.Data.Answer}"))
.Publish(context => new AnswerReadyEvent(context.Instance))
.TransitionTo(AnswerReady)
.Finalize(),
Ignore(Requesting),
Ignore(Validating)
);
SetCompletedWhenFinalized();
}
public State Requested { get; private set; }
public State RequestValid { get; private set; }
public State AnswerReady { get; private set; }
public State Error { get; private set; }
//Someone is sending a request to interprete
public Event<IRequesting> Requesting { get; private set; }
//Request is validated
public Event<IValidating> Validating { get; private set; }
//Request is interpreted
public Event<IInterpreting> Interpreting { get; private set; }
class ValidationNeededEvent : IValidationNeeded
{
readonly InterpreterInstance _instance;
public ValidationNeededEvent(InterpreterInstance instance)
{
_instance = instance;
}
public Guid RequestId => _instance.CorrelationId;
public Request Request => _instance.Request;
}
class InterpretationNeededEvent : IInterpretationNeeded
{
readonly InterpreterInstance _instance;
public InterpretationNeededEvent(InterpreterInstance instance)
{
_instance = instance;
}
public Guid RequestId => _instance.CorrelationId;
}
class AnswerReadyEvent : IAnswerReady
{
readonly InterpreterInstance _instance;
public AnswerReadyEvent(InterpreterInstance instance)
{
_instance = instance;
}
public Guid RequestId => _instance.CorrelationId;
}
}
Then I have services like this:
public class RequestService : ServiceControl
{
readonly IScheduler scheduler;
IBusControl busControl;
BusHandle busHandle;
InterpreterStateMachine machine;
InMemorySagaRepository<InterpreterInstance> repository;
public RequestService()
{
scheduler = CreateScheduler();
}
public bool Start(HostControl hostControl)
{
Console.WriteLine("Creating bus...");
machine = new InterpreterStateMachine();
repository = new InMemorySagaRepository<InterpreterInstance>();
busControl = Bus.Factory.CreateUsingRabbitMq(x =>
{
IRabbitMqHost host = x.Host(new Uri(/*rabbitMQ server*/), h =>
{
/*credentials*/
});
x.UseInMemoryScheduler();
x.ReceiveEndpoint(host, "interpreting_answer", e =>
{
e.PrefetchCount = 5; //?
e.StateMachineSaga(machine, repository);
});
x.ReceiveEndpoint(host, "2", e =>
{
e.PrefetchCount = 1;
x.UseMessageScheduler(e.InputAddress);
//Scheduling !?
e.Consumer(() => new ScheduleMessageConsumer(scheduler));
e.Consumer(() => new CancelScheduledMessageConsumer(scheduler));
});
});
Console.WriteLine("Starting bus...");
try
{
busHandle = MassTransit.Util.TaskUtil.Await<BusHandle>(() => busControl.StartAsync());
scheduler.JobFactory = new MassTransitJobFactory(busControl);
scheduler.Start();
}
catch (Exception)
{
scheduler.Shutdown();
throw;
}
return true;
}
public bool Stop(HostControl hostControl)
{
Console.WriteLine("Stopping bus...");
scheduler.Standby();
if (busHandle != null) busHandle.Stop();
scheduler.Shutdown();
return true;
}
static IScheduler CreateScheduler()
{
ISchedulerFactory schedulerFactory = new StdSchedulerFactory();
IScheduler scheduler = MassTransit.Util.TaskUtil.Await<IScheduler>(() => schedulerFactory.GetScheduler()); ;
return scheduler;
}
}
My questions are:
How do I send the "intial" request, so that the state machine will transition to my initial state
How do I "react" within the consumers to check the data that were sent and then send new data like in 1?
Okay I figured it out. I probably had problems because I'm not only new to Masstransit/Automatonymous and RabbitMQ, but also don't have much experience with C# yet.
So if anyone ever will have the same problem, here is what you need:
Given the above example there are three different types plus some small interfaces needed:
A sender (in this case the "requester") including a specific consumer
A service that consumes specific message types (the "validator" and "interpreter")
A service that holds the state machine without a specific consumer
Some "contracts", which are interfaces defining the type of message that's sent/consumed
1) This is the sender:
using InterpreterStateMachine.Contracts;
using MassTransit;
using System;
using System.Threading.Tasks;
namespace InterpreterStateMachine.Requester
{
class Program
{
private static IBusControl _busControl;
static void Main(string[] args)
{
var busControl = ConfigureBus();
busControl.Start();
Console.WriteLine("Enter request or quit to exit: ");
while (true)
{
Console.Write("> ");
String value = Console.ReadLine();
if ("quit".Equals(value,StringComparison.OrdinalIgnoreCase))
break;
if (value != null)
{
String[] values = value.Split(';');
foreach (String v in values)
{
busControl.Publish<IRequesting>(new
{
Request = new Request(v),
TimeStamp = DateTime.UtcNow
});
}
}
}
busControl.Stop();
}
static IBusControl ConfigureBus()
{
if (null == _busControl)
{
_busControl = Bus.Factory.CreateUsingRabbitMq(cfg =>
{
var host = cfg.Host(new Uri(/*rabbitMQ server*/), h =>
{
/*credentials*/
});
cfg.ReceiveEndpoint(host, "answer_ready", e =>
{
e.Durable = true;
//here the consumer is registered
e.Consumer<AnswerConsumer>();
});
});
_busControl.Start();
}
return _busControl;
}
//here comes the actual logic of the consumer, which consumes a "contract"
class AnswerConsumer : IConsumer<IAnswerReady>
{
public async Task Consume(ConsumeContext<IAnswerReady> context)
{
await Console.Out.WriteLineAsync($"\nReceived Answer for \"{context.Message.Request.RequestString}\": {context.Message.Answer}.");
await Console.Out.WriteAsync(">");
}
}
}
}
2) This is the service (here it is the validation sercive)
using InterpreterStateMachine.Contracts;
using MassTransit;
using MassTransit.QuartzIntegration;
using MassTransit.RabbitMqTransport;
using Quartz;
using Quartz.Impl;
using System;
using System.Threading.Tasks;
using Topshelf;
namespace InterpreterStateMachine.Validator
{
public class ValidationService : ServiceControl
{
readonly IScheduler _scheduler;
static IBusControl _busControl;
BusHandle _busHandle;
public static IBus Bus => _busControl;
public ValidationService()
{
_scheduler = CreateScheduler();
}
public bool Start(HostControl hostControl)
{
Console.WriteLine("Creating bus...");
_busControl = MassTransit.Bus.Factory.CreateUsingRabbitMq(x =>
{
IRabbitMqHost host = x.Host(new Uri(/*rabbitMQ server*/), h =>
{
/*credentials*/
});
x.UseInMemoryScheduler();
x.UseMessageScheduler(new Uri(RabbitMqServerAddress));
x.ReceiveEndpoint(host, "validation_needed", e =>
{
e.PrefetchCount = 1;
e.Durable = true;
//again this is how the consumer is registered
e.Consumer<RequestConsumer>();
});
});
Console.WriteLine("Starting bus...");
try
{
_busHandle = MassTransit.Util.TaskUtil.Await<BusHandle>(() => _busControl.StartAsync());
_scheduler.JobFactory = new MassTransitJobFactory(_busControl);
_scheduler.Start();
}
catch (Exception)
{
_scheduler.Shutdown();
throw;
}
return true;
}
public bool Stop(HostControl hostControl)
{
Console.WriteLine("Stopping bus...");
_scheduler.Standby();
_busHandle?.Stop();
_scheduler.Shutdown();
return true;
}
static IScheduler CreateScheduler()
{
ISchedulerFactory schedulerFactory = new StdSchedulerFactory();
IScheduler scheduler = MassTransit.Util.TaskUtil.Await<IScheduler>(() => schedulerFactory.GetScheduler());
return scheduler;
}
}
//again here comes the actual consumer logic, look how the message is re-published after it was checked
class RequestConsumer : IConsumer<IValidationNeeded>
{
public async Task Consume(ConsumeContext<IValidationNeeded> context)
{
await Console.Out.WriteLineAsync($"(c) Received {context.Message.Request.RequestString} for validation (Id: {context.Message.RequestId}).");
context.Message.Request.IsValid = context.Message.Request.RequestString.Contains("=");
//send the new message on the "old" context
await context.Publish<IValidating>(new
{
Request = context.Message.Request,
IsValid = context.Message.Request.IsValid,
TimeStamp = DateTime.UtcNow,
RequestId = context.Message.RequestId
});
}
}
}
The validator consumes the contract "IValidationNeeded" and then publishes the contract "IValidating", which then will be consumed by the state machine itself (the "Validating" event).
3) The difference between a consumer service and the sate machine service lies withing the "ReceiveEndpoint". Here is no consumer registered, but the state machine is set:
...
InterpreterStateMachine _machine = new InterpreterStateMachine();
InMemorySagaRepository<InterpreterInstance> _repository = new InMemorySagaRepository<InterpreterInstance>();
...
x.ReceiveEndpoint(host, "state_machine", e =>
{
e.PrefetchCount = 1;
//here the state machine is set
e.StateMachineSaga(_machine, _repository);
e.Durable = false;
});
4) Last but not least, the contracts are pretty small and look like this:
using System;
namespace InterpreterStateMachine.Contracts
{
public interface IValidationNeeded
{
Guid RequestId { get; }
Request Request { get; }
}
}
So overall it's pretty straightforward, I just had to use my brain :D
I hope this will help someone.