Brows.ProcessAgent 1.0.0

Brows.ProcessAgent

Launch a process and asynchronously collect its standard output and standard error as lines.

Install the package with dotnet add package Brows.ProcessAgent.

Run a process

ProcessAgent configures the executable and starts it. Start returns a Task<IProcessProxy> that completes after the process exits and its redirected output has been read; awaiting it gives you the proxy. Use OnProxyCreated if you need to observe the proxy while the process is running:

using Brows.Diagnostics;
using System;
using System.Threading;
using System.Threading.Tasks;

static async Task RunAsync(CancellationToken cancellationToken) {
    var agent = new ProcessAgent {
        FileName = "dotnet",
        Arguments = "--info"
    };

    var proxy = await agent.Start(cancellationToken);

    foreach (var item in proxy.Stream.LineItems) {
        var writer = item.Kind == ProcessOutputKind.StandardError
            ? Console.Error
            : Console.Out;
        writer.WriteLine(item.Line);
    }
}

LineItems contains completed lines from both output streams. Each item identifies its source with ProcessOutputKind. The collection is read-only and observable; read it from the returned proxy after Start completes, or observe the proxy supplied through OnProxyCreated and its collection-change notifications while the process is running.

Configuration

Set ProcessAgent properties before calling Start:

When a synchronization context is available, the default SynchronizeWithCurrentContext setting lets UI-bound observers receive collection changes on that context. Without a current context, changes are dispatched on the thread pool. Set SynchronizeWithCurrentContext to false to dispatch collection changes on the thread pool even when a context is available. Only LineItems changes are marshalled; CurrentItem and Line property-change notifications are raised on the output-reading thread. Prefer awaiting Start rather than synchronously blocking on it.

The process's standard input is closed immediately after it starts, so processes that read input receive end-of-file.

Set OnErrorCaught to handle exceptions encountered while closing standard input or retrieving the process exit code and exit time. If it is null, those exceptions fault the returned task. An exception is considered handled when the callback returns normally; exceptions from process startup and output reading are not sent to it.

The OnProxyCreated callback runs synchronously before process startup, but is skipped if cancellation is requested before the callback is invoked; set it to null to omit it. The proxy's Stream is initialized after the process starts. Cancel the supplied token to request termination of the process and cancel the returned task.

Supported frameworks

.NET Framework 4.0 and 4.6.2, .NET Standard 2.0, .NET Core 3.1, and .NET 6, .NET 8, and .NET 10.