public async Task ListenToEvents(string connString)
{
signalRHubHelper = new SignalRHubHelper(connString);
var hubUrl = signalRHubHelper.ClientUrl("default_hub");
// define a connection to receive published events
signalRHubConnection = new HubConnectionBuilder().WithUrl(hubUrl, option =>
{
option.AccessTokenProvider = () =>
{
var token = signalRHubHelper.GenerateAccessToken(hubUrl, "user-x");
return(Task.FromResult(token));
};
}).Build();
// define an event handler for received messages
signalRHubConnection.On <string, string>("StatusChanged", (deviceId, status) =>
{
Console.WriteLine($"Device {deviceId} changed status to {status}");
});
// start listening to published events
await signalRHubConnection.StartAsync();
Console.WriteLine("Listening for events...");
}
async Task InitSignalR()
{
var configBuilder = new ConfigurationBuilder();
configBuilder.AddUserSecrets("a0aa8545-9a28-485e-8218-9851c41dcfbb");
var config = configBuilder.Build();
// copy the CONNECTION STRING value from the Azure Portal under SingalR > [item] > Keys (under Settings)
// then in the csproj dir, run dotnet user-secrets set "signalRConnString" "conn_string_value"
// see https://docs.microsoft.com/en-us/aspnet/core/security/app-secrets?view=aspnetcore-2.2&tabs=windows
var connStr = config["signalRConnString"];
if (string.IsNullOrEmpty(connStr))
{
throw new ArgumentNullException(nameof(connStr), "set the CONNECTION STRING value from the Azure Portal under SingalR > [item] > Keys (under Settings)");
}
signalRHubHelper = new SignalRHubHelper(connStr);
signalRApiHttpClient = new HttpClient();
signalRApiClient = new SignalRApiClient(signalRApiHttpClient, signalRHubHelper);
var hubUrl = signalRHubHelper.ClientUrl(hubName: "default");
signalRHubConnection = new HubConnectionBuilder().WithUrl(hubUrl, option =>
{
option.AccessTokenProvider = () =>
{
var token = signalRHubHelper.GenerateAccessToken(hubUrl, "user-x");
return(Task.FromResult(token));
};
}).Build();
signalRHubConnection.On <int, string>("StatusChanged", (tableId, status) =>
{
Dispatcher.Invoke(() =>
{
if (tblControlsById.TryGetValue(tableId, out TableStatusControl tblControl))
{
tblControl.Status = status;
lblLastAction.Content = $"Status updated on {DateTime.Now}";
}
});
});
SetupConnectionRetry();
await signalRHubConnection.StartAsync();
lblConnStatus.Content = "Online";
lblConnStatus.Background = Brushes.SeaGreen;
lblLastAction.Content = $"Connected on {DateTime.Now}";
}