ProcessX

ProcessX simplifies call an external process with the aync streams in C# 8.0 without complex Process code. You can receive standard output results by await foreach, it is completely asynchronous and realtime.

Table of Contents

• Getting Started
• Cancellation
• Raw Process/StdError Stream
• Read Binary Data
• Change acceptable exit codes
• Reference
• Competitor
• License

Getting Started

Install library from NuGet that support from .NET Standard 2.0.

PM> Install-Package ProcessX

Main API is only Cysharp.Diagnostics.ProcessX.StartAsync and throws ProcessErrorException when error detected.

• Simple, only write single string command like the shell script.
• Asynchronous, by C# 8.0 async streams.
• Manage Error, handling exitcode and stderror.

using Cysharp.Diagnostics; // using namespace

// async iterate.
await foreach (string item in ProcessX.StartAsync("dotnet --info"))
{
    Console.WriteLine(item);
}

// receive buffered result(similar as WaitForExit).
string[] result = await ProcessX.StartAsync("dotnet --info").ToTask();

// like the shell exec, write all data to console.
await ProcessX.StartAsync("dotnet --info").WriteLineAllAsync();

// when ExitCode is not 0 or StandardError is exists, throws ProcessErrorException
try
{
    await foreach (var item in ProcessX.StartAsync("dotnet --foo --bar")) { }
}
catch (ProcessErrorException ex)
{
    // int .ExitCode
    // string[] .ErrorOutput
    Console.WriteLine(ex.ToString());
}

Cancellation

to Cancel, you can use WithCancellation of IAsyncEnumerable.

// when cancel has been called and process still exists, call process kill before exit.
await foreach (var item in ProcessX.StartAsync("dotnet --info").WithCancellation(cancellationToken))
{
    Console.WriteLine(item);
}

timeout, you can use CancellationTokenSource(delay).

using (var cts = new CancellationTokenSource(TimeSpan.FromSeconds(1)))
{
    await foreach (var item in ProcessX.StartAsync("dotnet --info").WithCancellation(cts.Token))
    {
        Console.WriteLine(item);
    }
}

Raw Process/StdError Stream

In default, when stdError is used, buffering error messages and throws ProcessErrorException with error messages after process exited. If you want to use stdError in streaming or avoid throws error when process using stderror as progress, diagnostics, you can use GetDualAsyncEnumerable method. Also GetDualAsyncEnumerable can get raw Process, you can use ProcessID, StandardInput etc.

// first argument is Process, if you want to know ProcessID, use StandardInput, use it.
var (_, stdOut, stdError) = ProcessX.GetDualAsyncEnumerable("dotnet --foo --bar");

var consumeStdOut = Task.Run(async () =>
{
    await foreach (var item in stdOut)
    {
        Console.WriteLine("STDOUT: " + item);
    }
});

var errorBuffered = new List<string>();
var consumeStdError = Task.Run(async () =>
{
    await foreach (var item in stdError)
    {
        Console.WriteLine("STDERROR: " + item);
        errorBuffered.Add(item);
    }
});

try
{
    await Task.WhenAll(consumeStdOut, consumeStdError);
}
catch (ProcessErrorException ex)
{
    // stdout iterator throws exception when exitcode is not 0.
    Console.WriteLine("ERROR, ExitCode: " + ex.ExitCode);

    // ex.ErrorOutput is empty, if you want to use it, buffer yourself.
    // Console.WriteLine(string.Join(Environment.NewLine, errorBuffered));
}

Read Binary Data

If stdout is binary data, you can use StartReadBinaryAsync to read byte[].

byte[] bin = await ProcessX.StartReadBinaryAsync($"...");

Change acceptable exit codes

In default, ExitCode is not 0 throws ProcessErrorException. You can change acceptable exit codes globally by ProcessX.AcceptableExitCodes property. Default is [0].

Reference

ProcessX.StartAsync overloads, you can set workingDirectory, environmentVariable, encoding.

// return ProcessAsyncEnumerable
StartAsync(string command, string? workingDirectory = null, IDictionary<string, string>? environmentVariable = null, Encoding? encoding = null)
StartAsync(string fileName, string? arguments, string? workingDirectory = null, IDictionary<string, string>? environmentVariable = null, Encoding? encoding = null)
StartAsync(ProcessStartInfo processStartInfo)

// return (Process, ProcessAsyncEnumerable, ProcessAsyncEnumerable)
GetDualAsyncEnumerable(string command, string? workingDirectory = null, IDictionary<string, string>? environmentVariable = null, Encoding? encoding = null)
GetDualAsyncEnumerable(string fileName, string? arguments, string? workingDirectory = null, IDictionary<string, string>? environmentVariable = null, Encoding? encoding = null)
GetDualAsyncEnumerable(ProcessStartInfo processStartInfo)

// return Task<byte[]>
StartReadBinaryAsync(string command, string? workingDirectory = null, IDictionary<string, string>? environmentVariable = null, Encoding? encoding = null)
StartReadBinaryAsync(string fileName, string? arguments, string? workingDirectory = null, IDictionary<string, string>? environmentVariable = null, Encoding? encoding = null)
StartReadBinaryAsync(ProcessStartInfo processStartInfo)

// return Task<string[]>
ToTask(CancellationToken cancellationToken = default)

// return Task
WriteLineAllAsync(CancellationToken cancellationToken = default)

Competitor

• Tyrrrz/CliWrap - Wrapper for command line interfaces.
• jamesmanning/RunProcessAsTask - Simple wrapper around System.Diagnostics.Process to expose it as a System.Threading.Tasks.Task.

License

This library is under the MIT License.