HubConnectionExtensions.StreamAsChannelAsync.cs

// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System;
using System.Threading;
using System.Threading.Tasks;
using System.Threading.Channels;

namespace Microsoft.AspNetCore.SignalR.Client
{
    /// <summary>
    /// Extension methods for <see cref="HubConnectionExtensions"/>.
    /// </summary>
    public static partial class HubConnectionExtensions
    {
        /// <summary>
        /// Invokes a streaming hub method on the server using the specified method name and return type.
        /// </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="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 Task<ChannelReader<TResult>> StreamAsChannelAsync<TResult>(this HubConnection hubConnection, string methodName, CancellationToken cancellationToken = default)
        {
            return hubConnection.StreamAsChannelCoreAsync<TResult>(methodName, Array.Empty<object>(), cancellationToken);
        }

        /// <summary>
        /// Invokes a streaming hub method on the server using the specified method name, return type and argument.
        /// </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="arg1">The first argument.</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 Task<ChannelReader<TResult>> StreamAsChannelAsync<TResult>(this HubConnection hubConnection, string methodName, object arg1, CancellationToken cancellationToken = default)
        {
            return hubConnection.StreamAsChannelCoreAsync<TResult>(methodName, new[] { arg1 }, cancellationToken);
        }

        /// <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="arg1">The first argument.</param>
        /// <param name="arg2">The second argument.</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 Task<ChannelReader<TResult>> StreamAsChannelAsync<TResult>(this HubConnection hubConnection, string methodName, object arg1, object arg2, CancellationToken cancellationToken = default)
        {
            return hubConnection.StreamAsChannelCoreAsync<TResult>(methodName, new[] { arg1, arg2 }, cancellationToken);
        }

        /// <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="arg1">The first argument.</param>
        /// <param name="arg2">The second argument.</param>
        /// <param name="arg3">The third argument.</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 Task<ChannelReader<TResult>> StreamAsChannelAsync<TResult>(this HubConnection hubConnection, string methodName, object arg1, object arg2, object arg3, CancellationToken cancellationToken = default)
        {
            return hubConnection.StreamAsChannelCoreAsync<TResult>(methodName, new[] { arg1, arg2, arg3 }, cancellationToken);
        }

        /// <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="arg1">The first argument.</param>
        /// <param name="arg2">The second argument.</param>
        /// <param name="arg3">The third argument.</param>
        /// <param name="arg4">The fourth argument.</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 Task<ChannelReader<TResult>> StreamAsChannelAsync<TResult>(this HubConnection hubConnection, string methodName, object arg1, object arg2, object arg3, object arg4, CancellationToken cancellationToken = default)
        {
            return hubConnection.StreamAsChannelCoreAsync<TResult>(methodName, new[] { arg1, arg2, arg3, arg4 }, cancellationToken);
        }

        /// <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="arg1">The first argument.</param>
        /// <param name="arg2">The second argument.</param>
        /// <param name="arg3">The third argument.</param>
        /// <param name="arg4">The fourth argument.</param>
        /// <param name="arg5">The fifth argument.</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 Task<ChannelReader<TResult>> StreamAsChannelAsync<TResult>(this HubConnection hubConnection, string methodName, object arg1, object arg2, object arg3, object arg4, object arg5, CancellationToken cancellationToken = default)
        {
            return hubConnection.StreamAsChannelCoreAsync<TResult>(methodName, new[] { arg1, arg2, arg3, arg4, arg5 }, cancellationToken);
        }

        /// <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="arg1">The first argument.</param>
        /// <param name="arg2">The second argument.</param>
        /// <param name="arg3">The third argument.</param>
        /// <param name="arg4">The fourth argument.</param>
        /// <param name="arg5">The fifth argument.</param>
        /// <param name="arg6">The sixth argument.</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 Task<ChannelReader<TResult>> StreamAsChannelAsync<TResult>(this HubConnection hubConnection, string methodName, object arg1, object arg2, object arg3, object arg4, object arg5, object arg6, CancellationToken cancellationToken = default)
        {
            return hubConnection.StreamAsChannelCoreAsync<TResult>(methodName, new[] { arg1, arg2, arg3, arg4, arg5, arg6 }, cancellationToken);
        }

        /// <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="arg1">The first argument.</param>
        /// <param name="arg2">The second argument.</param>
        /// <param name="arg3">The third argument.</param>
        /// <param name="arg4">The fourth argument.</param>
        /// <param name="arg5">The fifth argument.</param>
        /// <param name="arg6">The sixth argument.</param>
        /// <param name="arg7">The seventh argument.</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 Task<ChannelReader<TResult>> StreamAsChannelAsync<TResult>(this HubConnection hubConnection, string methodName, object arg1, object arg2, object arg3, object arg4, object arg5, object arg6, object arg7, CancellationToken cancellationToken = default)
        {
            return hubConnection.StreamAsChannelCoreAsync<TResult>(methodName, new[] { arg1, arg2, arg3, arg4, arg5, arg6, arg7 }, cancellationToken);
        }

        /// <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="arg1">The first argument.</param>
        /// <param name="arg2">The second argument.</param>
        /// <param name="arg3">The third argument.</param>
        /// <param name="arg4">The fourth argument.</param>
        /// <param name="arg5">The fifth argument.</param>
        /// <param name="arg6">The sixth argument.</param>
        /// <param name="arg7">The seventh argument.</param>
        /// <param name="arg8">The eighth argument.</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 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, CancellationToken cancellationToken = default)
        {
            return hubConnection.StreamAsChannelCoreAsync<TResult>(methodName, new[] { arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8 }, cancellationToken);
        }

        /// <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="arg1">The first argument.</param>
        /// <param name="arg2">The second argument.</param>
        /// <param name="arg3">The third argument.</param>
        /// <param name="arg4">The fourth argument.</param>
        /// <param name="arg5">The fifth argument.</param>
        /// <param name="arg6">The sixth argument.</param>
        /// <param name="arg7">The seventh argument.</param>
        /// <param name="arg8">The eighth argument.</param>
        /// <param name="arg9">The ninth argument.</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 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, CancellationToken cancellationToken = default)
        {
            return hubConnection.StreamAsChannelCoreAsync<TResult>(methodName, new[] { arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9 }, cancellationToken);
        }

        /// <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="arg1">The first argument.</param>
        /// <param name="arg2">The second argument.</param>
        /// <param name="arg3">The third argument.</param>
        /// <param name="arg4">The fourth argument.</param>
        /// <param name="arg5">The fifth argument.</param>
        /// <param name="arg6">The sixth argument.</param>
        /// <param name="arg7">The seventh argument.</param>
        /// <param name="arg8">The eighth argument.</param>
        /// <param name="arg9">The ninth argument.</param>
        /// <param name="arg10">The tenth argument.</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 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);
        }

        /// <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>();

            // 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;
        }
    }
}