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Improve shutdown of SignalR .NET client sample (#10675)

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Stephen Halter 2019-06-05 21:31:04 -07:00 committed by GitHub
parent c518cff370
commit 511761627a
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1 changed files with 59 additions and 55 deletions
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114
src/SignalR/samples/ClientSample/HubSample.cs
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@ -2,7 +2,6 @@
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
using System;
using System.IO;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.AspNetCore.SignalR.Client;
@ -29,7 +28,9 @@ namespace ClientSample
public static async Task<int> ExecuteAsync(string baseUrl)
{
var uri = baseUrl == null ? new Uri("net.tcp://127.0.0.1:9001") : new Uri(baseUrl);
Console.WriteLine("Connecting to {0}", uri);
var connectionBuilder = new HubConnectionBuilder()
.ConfigureLogging(logging =>
{
@ -52,88 +53,91 @@ namespace ClientSample
connectionBuilder.WithAutomaticReconnect();
using var closedTokenSource = new CancellationTokenSource();
var connection = connectionBuilder.Build();
Console.CancelKeyPress += (sender, a) =>
try
{
a.Cancel = true;
connection.DisposeAsync().GetAwaiter().GetResult();
};
// Set up handler
connection.On<string>("Send", Console.WriteLine);
CancellationTokenSource closedTokenSource = null;
connection.Closed += e =>
{
// This should never be null by the time this fires
closedTokenSource.Cancel();
Console.WriteLine("Connection closed...");
return Task.CompletedTask;
};
do
{
// Dispose the previous token
closedTokenSource?.Dispose();
// Create a new token for this run
closedTokenSource = new CancellationTokenSource();
// Connect to the server
} while (!await ConnectAsync(connection));
Console.WriteLine("Connected to {0}", uri);
// Handle the connected connection
while (true)
{
try
Console.CancelKeyPress += (sender, a) =>
{
a.Cancel = true;
closedTokenSource.Cancel();
connection.StopAsync().GetAwaiter().GetResult();
};
// Set up handler
connection.On<string>("Send", Console.WriteLine);
connection.Closed += e =>
{
Console.WriteLine("Connection closed...");
closedTokenSource.Cancel();
return Task.CompletedTask;
};
if (!await ConnectAsync(connection, closedTokenSource.Token))
{
Console.WriteLine("Failed to establish a connection to '{0}' because the CancelKeyPress event fired first. Exiting...", uri);
return 0;
}
Console.WriteLine("Connected to {0}", uri);
// Handle the connected connection
while (true)
{
// If the underlying connection closes while waiting for user input, the user will not observe
// the connection close aside from "Connection closed..." being printed to the console. That's
// because cancelling Console.ReadLine() is a royal pain.
var line = Console.ReadLine();
if (line == null || closedTokenSource.Token.IsCancellationRequested)
{
Console.WriteLine("Exiting...");
break;
}
await connection.InvokeAsync<object>("Send", line);
}
catch (ObjectDisposedException)
{
// We're shutting down the client
break;
}
catch (Exception ex)
{
// Send could have failed because the connection closed
// Continue to loop because we should be reconnecting.
Console.WriteLine(ex);
try
{
await connection.InvokeAsync<object>("Send", line);
}
catch when (closedTokenSource.IsCancellationRequested)
{
// We're shutting down the client
Console.WriteLine("Failed to send '{0}' because the CancelKeyPress event fired first. Exiting...", line);
break;
}
catch (Exception ex)
{
// Send could have failed because the connection closed
// Continue to loop because we should be reconnecting.
Console.WriteLine(ex);
}
}
}
finally
{
await connection.StopAsync();
}
return 0;
}
private static async Task<bool> ConnectAsync(HubConnection connection)
private static async Task<bool> ConnectAsync(HubConnection connection, CancellationToken token)
{
// Keep trying to until we can start
while (true)
{
try
{
await connection.StartAsync();
await connection.StartAsync(token);
return true;
}
catch (ObjectDisposedException)
catch when (token.IsCancellationRequested)
{
// Client side killed the connection
return false;
}
catch (Exception)
catch
{
Console.WriteLine("Failed to connect, trying again in 5000(ms)");