处理来自p.WaitForExit（）与RedirectStandardOutput大量输出= TRUE [英] Handle large amounts of output from p.WaitForExit() with RedirectStandardOutput = True

问题描述

因为这里所讨论的ProcessStartInfo挂在＆QUOT; WaitForExit＆QUOT;？为什么 - ？调用p.WaitForExit（）具有较大的输出罢了，OutputStream中和导致死锁的过程和输出流等待对方

As discussed here ProcessStartInfo hanging on "WaitForExit"? Why? - calling p.WaitForExit() with a large output fills the OutputStream and causes a deadlock as the process and the output stream wait for each other.

我的code，例如：

Dim p = New Process()
Dim ReturnValue As Boolean = False
p.StartInfo = New ProcessStartInfo(LynxPath, "-dump -nolist -width 1000 " & HtmlBuffer)
p.StartInfo.WorkingDirectory = WorkingRoot
p.StartInfo.UseShellExecute = False
p.StartInfo.RedirectStandardOutput = True
p.StartInfo.RedirectStandardError = True
p.StartInfo.WindowStyle = ProcessWindowStyle.Hidden
p.StartInfo.CreateNoWindow = True
p.Start()
ReturnValue = p.WaitForExit(5000)

在与山猫的大输出处理线程挂起，除非我使用超时如上，输出修剪当输出缓冲区满 - 意为任何输出我不读心不是完整的

When dealing with a large output from LYNX the thread hangs unless i use a timeout as above, and the output is trimmed when the output buffer gets full - meaning any output i do read isnt complete.

张贴在问题中的C＃解决方案上面似乎来解决这个问题通过利用 OutputDataReceived 活动的进程类。我的问题是但是转换的C＃code到vb.net 3.5，我跑它通过正常的转换路径，它吐出来：

The c# solution posted in the question above seems to get around this by making use of the OutputDataReceived event on the process class. My problem however is converting that c# code into vb.net 3.5, i ran it through the normal conversion routes and it spat out:

Using process As New Process()
    process.StartInfo.FileName = filename
    process.StartInfo.Arguments = arguments
    process.StartInfo.UseShellExecute = False
    process.StartInfo.RedirectStandardOutput = True
    process.StartInfo.RedirectStandardError = True

    Dim output As New StringBuilder()
    Dim [error] As New StringBuilder()

    Using outputWaitHandle As New AutoResetEvent(False)
        Using errorWaitHandle As New AutoResetEvent(False)
            process.OutputDataReceived += Function(sender, e) 
            If e.Data Is Nothing Then
                outputWaitHandle.[Set]()
            Else
                output.AppendLine(e.Data)
            End If

End Function
            process.ErrorDataReceived += Function(sender, e) 
            If e.Data Is Nothing Then
                errorWaitHandle.[Set]()
            Else
                [error].AppendLine(e.Data)
            End If

End Function

            process.Start()

            process.BeginOutputReadLine()
            process.BeginErrorReadLine()

                ' Process completed. Check process.ExitCode here.
            If process.WaitForExit(timeout) AndAlso outputWaitHandle.WaitOne(timeout) AndAlso errorWaitHandle.WaitOne(timeout) Then
                ' Timed out.
            Else
            End If
        End Using
    End Using
End Using

不过Visual Studio 2008中标记的功能declerations为无效语法（内联等方法，因为这是在4.5以后怎么想吗？），如何将一个利用这个例子在3.5 - 不能完全得到我的头轮它

However Visual Studio 2008 flags the function declerations as invalid syntax (Inline methods such as this are in 4.5 onwards i think?), how would one make use of this example in 3.5 - cant quite get my head round it.

编辑：刚发现此链接：http://msdn.microsoft.com/en-us/library/system.diagnostics.process.outputdatareceived.aspx - 试图弄明白现在

just found this link: http://msdn.microsoft.com/en-us/library/system.diagnostics.process.outputdatareceived.aspx - Trying to figure it out now

推荐答案

这就是我们ultimitly想出了，它需要一个HTML字符串，将其写入到文件，然后用猞猁打开它，猞猁输出随后抓获事件处理（用于处理大量输出）和填充纯文本字符串：

This is what we ultimitly came up with, it takes a html string, writes it to a file then opens it with lynx, The lynx output is then captured using an event handle (which handles large amounts of output) and populates a plain text string:

Function ConvertHtmlToPlainText(ByVal HtmlString As String) As String

    ' Define FileBuffer Path
    Dim HtmlBuffer As String = WorkingRoot & "HtmlBuffer.html"

    ' Delete any old buffer files
    Try
        If File.Exists(HtmlBuffer) = True Then
            File.Delete(HtmlBuffer)
        End If
    Catch ex As Exception
        Return "Error: Deleting old buffer file: " & ex.Message
    End Try

    ' Write the HTML to the buffer file
    Try
        File.WriteAllText(WorkingRoot & "HtmlBuffer.html", HtmlString)
    Catch ex As Exception
        Return "Error: Writing new buffer file: " & ex.Message
    End Try

    ' Check the file was written OK
    If File.Exists(HtmlBuffer) = False Then
        Return "Error: HTML Buffer file was not written successfully."
    End If

    If File.Exists(LynxPath) = False Then
        Return "Error: Lynx.exe could not be found in path: " & LynxPath
    End If

    ' Read the buffer file with Lynx and capture plain text output
    Try
        LynxOutput = ""
        LynxOutputLineCount = 0
        Dim LynxProcess As New Process()
        LynxProcess.StartInfo = New ProcessStartInfo(LynxPath, "-dump -nolist -width 1000 " & HtmlBuffer)
        LynxProcess.StartInfo.UseShellExecute = False
        LynxProcess.StartInfo.RedirectStandardOutput = True
        LynxProcess.StartInfo.WindowStyle = ProcessWindowStyle.Hidden
        LynxProcess.StartInfo.CreateNoWindow = True
        AddHandler LynxProcess.OutputDataReceived, AddressOf LynxOutputHandle
        LynxProcess.StartInfo.RedirectStandardInput = True
        LynxProcess.Start()
        LynxProcess.BeginOutputReadLine()
        LynxProcess.WaitForExit()
        LynxProcess.Close()

        ' Return the rendered Text
        Return TrimEachLine(LynxOutput.Replace(vbLf & vbLf, vbLf))

    Catch ex As Exception
        Return "Error: Error running LYNX to parse the buffer: " & ex.Message
    End Try
End Function

Private Sub LynxOutputHandle(ByVal sendingProcess As Object, ByVal outLine As DataReceivedEventArgs)
    LynxOutputLineCount = LynxOutputLineCount + 1
    LynxOutput = LynxOutput & outLine.Data & vbLf
End Sub

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