Intro
很多时候我们可能会需要执行一段命令获取一个输出,遇到的比较典型的就是之前我们需要用 FFMpeg 实现视频的编码压缩水印等一系列操作,当时使用的是 FFMpegCore 这个类库,这个类库的实现原理是启动另外一个进程,启动 ffmpeg 并传递相应的处理参数,并根据进程输出获取处理进度
为了方便使用,实现了两个帮助类来方便的获取进程的输出,分别是 ProcessExecutor 和 CommandRunner,前者更为灵活,可以通过事件添加自己的额外事件订阅处理,后者为简化版,主要是只获取输出的场景,两者的实现原理大体是一样的,启动一个 Process,并监听其输出事件获取输出
ProcessExecutor
使用示例,这个示例是获取保存 nuget 包的路径的一个示例:
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using var executor = new ProcessExecutor( "dotnet" , "nuget locals global-packages -l" ); var folder = string .Empty; executor.OnOutputDataReceived += (sender, str) => { if (str is null ) return ; Console.WriteLine(str); if (str.StartsWith( "global-packages:" )) { folder = str.Substring( "global-packages:" .Length).Trim(); } }; executor.Execute(); Console.WriteLine(folder); |
ProcessExecutor
实现代码如下:
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public class ProcessExecutor : IDisposable { public event EventHandler< int > OnExited; public event EventHandler< string > OnOutputDataReceived; public event EventHandler< string > OnErrorDataReceived; protected readonly Process _process; protected bool _started; public ProcessExecutor( string exePath) : this ( new ProcessStartInfo(exePath)) { } public ProcessExecutor( string exePath, string arguments) : this ( new ProcessStartInfo(exePath, arguments)) { } public ProcessExecutor(ProcessStartInfo startInfo) { _process = new Process() { StartInfo = startInfo, EnableRaisingEvents = true , }; _process.StartInfo.UseShellExecute = false ; _process.StartInfo.CreateNoWindow = true ; _process.StartInfo.RedirectStandardOutput = true ; _process.StartInfo.RedirectStandardInput = true ; _process.StartInfo.RedirectStandardError = true ; } protected virtual void InitializeEvents() { _process.OutputDataReceived += (sender, args) => { if (args.Data != null ) { OnOutputDataReceived?.Invoke(sender, args.Data); } }; _process.ErrorDataReceived += (sender, args) => { if (args.Data != null ) { OnErrorDataReceived?.Invoke(sender, args.Data); } }; _process.Exited += (sender, args) => { if (sender is Process process) { OnExited?.Invoke(sender, process.ExitCode); } else { OnExited?.Invoke(sender, _process.ExitCode); } }; } protected virtual void Start() { if (_started) { return ; } _started = true ; _process.Start(); _process.BeginOutputReadLine(); _process.BeginErrorReadLine(); _process.WaitForExit(); } public async virtual Task SendInput( string input) { try { await _process.StandardInput.WriteAsync(input!); } catch (Exception e) { OnErrorDataReceived?.Invoke(_process, e.ToString()); } } public virtual int Execute() { InitializeEvents(); Start(); return _process.ExitCode; } public virtual async Task< int > ExecuteAsync() { InitializeEvents(); return await Task.Run(() => { Start(); return _process.ExitCode; }).ConfigureAwait( false ); } public virtual void Dispose() { _process.Dispose(); OnExited = null ; OnOutputDataReceived = null ; OnErrorDataReceived = null ; } } |
CommandExecutor
上面的这种方式比较灵活但有些繁琐,于是有了下面这个版本
使用示例:
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[Fact] public void HostNameTest() { if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows)) { return ; } var result = CommandRunner.ExecuteAndCapture( "hostname" ); var hostName = Dns.GetHostName(); Assert.Equal(hostName, result.StandardOut.TrimEnd()); Assert.Equal(0, result.ExitCode); } |
实现源码:
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public static class CommandRunner { public static int Execute( string commandPath, string arguments = null , string workingDirectory = null ) { using var process = new Process() { StartInfo = new ProcessStartInfo(commandPath, arguments ?? string .Empty) { UseShellExecute = false , CreateNoWindow = true , WorkingDirectory = workingDirectory ?? Environment.CurrentDirectory } }; process.Start(); process.WaitForExit(); return process.ExitCode; } public static CommandResult ExecuteAndCapture( string commandPath, string arguments = null , string workingDirectory = null ) { using var process = new Process() { StartInfo = new ProcessStartInfo(commandPath, arguments ?? string .Empty) { UseShellExecute = false , CreateNoWindow = true , RedirectStandardOutput = true , RedirectStandardError = true , WorkingDirectory = workingDirectory ?? Environment.CurrentDirectory } }; process.Start(); var standardOut = process.StandardOutput.ReadToEnd(); var standardError = process.StandardError.ReadToEnd(); process.WaitForExit(); return new CommandResult(process.ExitCode, standardOut, standardError); } } public sealed class CommandResult { public CommandResult( int exitCode, string standardOut, string standardError) { ExitCode = exitCode; StandardOut = standardOut; StandardError = standardError; } public string StandardOut { get ; } public string StandardError { get ; } public int ExitCode { get ; } } |
More
如果只要执行命令获取是否执行成功则使用 CommandRunner.Execute 即可,只获取输出和是否成功可以用 CommandRunner.ExecuteAndCapture 方法,如果想要进一步的添加事件订阅则使用 ProcessExecutor
Reference
https://github.com/rosenbjerg/FFMpegCore
https://github.com/WeihanLi/WeihanLi.Common/blob/dev/src/WeihanLi.Common/Helpers/ProcessExecutor.cs
https://github.com/WeihanLi/WeihanLi.Common/blob/dev/test/WeihanLi.Common.Test/HelpersTest/ProcessExecutorTest.cs
https://github.com/WeihanLi/WeihanLi.Common/blob/dev/test/WeihanLi.Common.Test/HelpersTest/CommandRunnerTest.cs
以上就是如何使用C# 捕获进程输出的详细内容,更多关于C# 捕获进程输出的资料请关注服务器之家其它相关文章!
原文链接:https://www.cnblogs.com/weihanli/p/13534390.html?utm_source=tuicool&utm_medium=referral