public static async Task <ChannelReader <TResult> > StreamAsChannelCoreAsync <TResult>(this HubConnection hubConnection, string methodName, object[] args, CancellationToken cancellationToken = default)
{
if (hubConnection == null)
{
throw new ArgumentNullException(nameof(hubConnection));
}
var inputChannel = await hubConnection.StreamAsChannelCoreAsync(methodName, typeof(TResult), args, cancellationToken);
var outputChannel = Channel.CreateUnbounded <TResult>();
// Local function to provide a way to run async code as fire-and-forget
// The output channel is how we signal completion to the caller.
async Task RunChannel()
{
try
{
while (await inputChannel.WaitToReadAsync())
{
while (inputChannel.TryRead(out var item))
{
while (!outputChannel.Writer.TryWrite((TResult)item))
{
if (!await outputChannel.Writer.WaitToWriteAsync())
{
// Failed to write to the output channel because it was closed. Nothing really we can do but abort here.
return;
}
}
}
}
// Manifest any errors in the completion task
await inputChannel.Completion;
}
catch (Exception ex)
{
outputChannel.Writer.TryComplete(ex);
}
finally
{
// This will safely no-op if the catch block above ran.
outputChannel.Writer.TryComplete();
}
}
_ = RunChannel();
return(outputChannel.Reader);
}
/// <summary>
/// Invokes a streaming hub method on the server using the specified method name, return type and arguments.
/// </summary>
/// <typeparam name="TResult">The return type of the streaming server method.</typeparam>
/// <param name="hubConnection">The hub connection.</param>
/// <param name="methodName">The name of the server method to invoke.</param>
/// <param name="args">The arguments used to invoke the server method.</param>
/// <param name="cancellationToken">The token to monitor for cancellation requests. The default value is <see cref="CancellationToken.None" />.</param>
/// <returns>
/// A <see cref="Task{TResult}"/> that represents the asynchronous invoke.
/// The <see cref="Task{TResult}.Result"/> property returns a <see cref="ChannelReader{T}"/> for the streamed hub method values.
/// </returns>
public static async Task <ChannelReader <TResult> > StreamAsChannelCoreAsync <TResult>(this HubConnection hubConnection, string methodName, object?[] args, CancellationToken cancellationToken = default)
{
if (hubConnection == null)
{
throw new ArgumentNullException(nameof(hubConnection));
}
var inputChannel = await hubConnection.StreamAsChannelCoreAsync(methodName, typeof(TResult), args, cancellationToken);
var outputChannel = Channel.CreateUnbounded <TResult>();
// Intentionally avoid passing the CancellationToken to RunChannel. The token is only meant to cancel the intial setup, not the enumeration.
_ = RunChannel(inputChannel, outputChannel);
return(outputChannel.Reader);
}
public static Task <ChannelReader <TResult> > StreamAsChannelAsync <TResult>(this HubConnection hubConnection, string methodName, object arg1, object arg2, object arg3, object arg4, object arg5, object arg6, object arg7, object arg8, object arg9, object arg10, CancellationToken cancellationToken = default)
{
return(hubConnection.StreamAsChannelCoreAsync <TResult>(methodName, new[] { arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9, arg10 }, cancellationToken));
}
public static Task <ChannelReader <TResult> > StreamAsChannelAsync <TResult>(this HubConnection hubConnection, string methodName, object arg1, CancellationToken cancellationToken = default)
{
return(hubConnection.StreamAsChannelCoreAsync <TResult>(methodName, new[] { arg1 }, cancellationToken));
}
public static Task <ChannelReader <TResult> > StreamAsChannelAsync <TResult>(this HubConnection hubConnection, string methodName, CancellationToken cancellationToken = default)
{
return(hubConnection.StreamAsChannelCoreAsync <TResult>(methodName, Array.Empty <object>(), cancellationToken));
}
