代理命令，分流命令

huangapple
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英文:

Proxy command that tees

问题

对于一个 PowerShell 功能请求（无论这是否是个好主意），我尝试创建了一个原型，使用了一个名为 Write-Table 的代理命令，基于 Format-Table 命令，它直接将数据写入主机，并根据 PassThru 开关的情况应该传递当前输入对象：

  1. function Write-Table {
  2.     [CmdletBinding(HelpUri='https://go.microsoft.com/fwlink/?LinkID=2096703')]
  3.     param(
  4.         [switch]
  5.         ${AutoSize},
  7.         [switch]
  8.         ${RepeatHeader},
  10.         [switch]
  11.         ${HideTableHeaders},
  13.         [switch]
  14.         ${Wrap},
  16.         [Parameter(Position=0)]
  17.         [System.Object[]]
  18.         ${Property},
  20.         [System.Object]
  21.         ${GroupBy},
  23.         [string]
  24.         ${View},
  26.         [switch]
  27.         ${ShowError},
  29.         [switch]
  30.         ${DisplayError},
  32.         [switch]
  33.         ${Force},
  35.         [ValidateSet('CoreOnly','EnumOnly','Both')]
  36.         [string]
  37.         ${Expand},
  39.         [Parameter(ValueFromPipeline=$true)]
  40.         [psobject]
  41.         ${InputObject},
  43.         [switch]
  44.         ${PassThru})
  45.     
  46.     begin
  47.     {
  48.         try {
  49.             $outBuffer = $null
  50.             if ($PSBoundParameters.TryGetValue('OutBuffer', [ref]$outBuffer))
  51.             {
  52.                 $PSBoundParameters['OutBuffer'] = 1
  53.             }
  55.             if ($PSBoundParameters.TryGetValue('PassThru', [ref]$outBuffer))
  56.             {
  57.                 $Null = $PSBoundParameters.Remove('PassThru')
  58.             }
  60.             $wrappedCmd = $ExecutionContext.InvokeCommand.GetCommand('Microsoft.PowerShell.Utility\Format-Table', [System.Management.Automation.CommandTypes]::Cmdlet)
  61.             $scriptCmd = {& $wrappedCmd @PSBoundParameters }
  63.             $steppablePipeline = $scriptCmd.GetSteppablePipeline($myInvocation.CommandOrigin)
  64.             $steppablePipeline.Begin($PSCmdlet)
  65.         } catch {
  66.             throw
  67.         }
  68.     }
  70.     process
  71.     {
  72.         try {
  73.             if ($PassThru) { $_ }
  74.             $steppablePipeline.Process($_)
  75.         } catch {
  76.             throw
  77.         }
  78.     }
  80.     end
  81.     {
  82.         try {
  83.             $steppablePipeline.End()
  84.         } catch {
  85.             throw
  86.         }
  87.     }
  89.     clean
  90.     {
  91.         if ($null -ne $steppablePipeline) {
  92.             $steppablePipeline.Clean()
  93.         }
  94.     }
  95.     <#
  96.     
  97.     .ForwardHelpTargetName Microsoft.PowerShell.Utility\Format-Table
  98.     .ForwardHelpCategory Cmdlet
  99.     
  100.     #>
  101. }

但不知何故，似乎当前的对象在传递给主机之前已从管道中移除（我不知道如何防止这种情况发生）：

  1. gci *.txt | Write-Table -PassThru | Get-Item # 最终意图: ... | Remove-Item
  2.     
  3.     Directory: C:\Users\Gebruiker\Downloads\temp
  5. Mode                 LastWriteTime         Length Name
  6. ----                 -------------         ------ ----
  7. -a---           7/20/2023  3:44 PM              0 file1.txt
  8. Get-Item: Cannot find path 'Microsoft.PowerShell.Commands.Internal.Format.FormatStartData' because it does not exist.
  9. Get-Item: Cannot find path 'Microsoft.PowerShell.Commands.Internal.Format.GroupStartData' because it does not exist.
  10. Get-Item: Cannot find path 'Microsoft.PowerShell.Commands.Internal.Format.FormatEntryData' because it does not exist.
  11. -a---           7/20/2023  3:44 PM              0 file2.txt
  12. Get-Item: Cannot find path 'Microsoft.PowerShell.Commands.Internal.Format.FormatEntryData' because it does not exist.
  13. -a---           7/20/2023  3:44 PM              0 file3.txt
  14. Get-Item: Cannot find path 'Microsoft.PowerShell.Commands.Internal.Format.FormatEntryData' because it does not exist.
  15. Get-Item: Cannot find path 'Microsoft.PowerShell.Commands.Internal.Format.GroupEndData' because it does not exist.
  16. Get-Item: Cannot find path 'Microsoft.PowerShell.Commands.Internal.Format.FormatEndData' because it does not exist.
  18. 是否有人能解释这里发生了什么问题，以及如何解决？
  20. <details>
  21. <summary>英文:</summary>
  23. For a [PowerShell feature request](https://github.com/PowerShell/PowerShell/issues/20001) (whether this is a good idea or not), I tried to create a prototype using a proxy command named `Write-Table` based on the `Format-Table` cmdlet that directly writes to the host and depending on the `PassThru` switch should pass the current input object:
  25.     function Write-Table {
  26.         [CmdletBinding(HelpUri=&#39;https://go.microsoft.com/fwlink/?LinkID=2096703&#39;)]
  27.         param(
  28.             [switch]
  29.             ${AutoSize},
  30.         
  31.             [switch]
  32.             ${RepeatHeader},
  33.         
  34.             [switch]
  35.             ${HideTableHeaders},
  36.         
  37.             [switch]
  38.             ${Wrap},
  39.         
  40.             [Parameter(Position=0)]
  41.             [System.Object[]]
  42.             ${Property},
  43.         
  44.             [System.Object]
  45.             ${GroupBy},
  46.         
  47.             [string]
  48.             ${View},
  49.         
  50.             [switch]
  51.             ${ShowError},
  52.         
  53.             [switch]
  54.             ${DisplayError},
  55.         
  56.             [switch]
  57.             ${Force},
  58.         
  59.             [ValidateSet(&#39;CoreOnly&#39;,&#39;EnumOnly&#39;,&#39;Both&#39;)]
  60.             [string]
  61.             ${Expand},
  62.         
  63.             [Parameter(ValueFromPipeline=$true)]
  64.             [psobject]
  65.             ${InputObject},
  66.         
  67.             [switch]
  68.             ${PassThru})
  69.         
  70.         begin
  71.         {
  72.             try {
  73.                 $outBuffer = $null
  74.                 if ($PSBoundParameters.TryGetValue(&#39;OutBuffer&#39;, [ref]$outBuffer))
  75.                 {
  76.                     $PSBoundParameters[&#39;OutBuffer&#39;] = 1
  77.                 }
  78.         
  79.                 if ($PSBoundParameters.TryGetValue(&#39;PassThru&#39;, [ref]$outBuffer))
  80.                 {
  81.                     $Null = $PSBoundParameters.Remove(&#39;PassThru&#39;)
  82.                 }
  83.         
  84.                 $wrappedCmd = $ExecutionContext.InvokeCommand.GetCommand(&#39;Microsoft.PowerShell.Utility\Format-Table&#39;, [System.Management.Automation.CommandTypes]::Cmdlet)
  85.                 $scriptCmd = {&amp; $wrappedCmd @PSBoundParameters }
  86.         
  87.                 $steppablePipeline = $scriptCmd.GetSteppablePipeline($myInvocation.CommandOrigin)
  88.                 $steppablePipeline.Begin($PSCmdlet)
  89.             } catch {
  90.                 throw
  91.             }
  92.         }
  93.         
  94.         process
  95.         {
  96.             try {
  97.                 if ($PassThru) { $_ }
  98.                 $steppablePipeline.Process($_)
  99.             } catch {
  100.                 throw
  101.             }
  102.         }
  103.         
  104.         end
  105.         {
  106.             try {
  107.                 $steppablePipeline.End()
  108.             } catch {
  109.                 throw
  110.             }
  111.         }
  112.         
  113.         clean
  114.         {
  115.             if ($null -ne $steppablePipeline) {
  116.                 $steppablePipeline.Clean()
  117.             }
  118.         }
  119.         &lt;#
  120.         
  121.         .ForwardHelpTargetName Microsoft.PowerShell.Utility\Format-Table
  122.         .ForwardHelpCategory Cmdlet
  123.         
  124.         #&gt;
  125.     }
  127. But somehow it appears that the current object is removed from the pipeline before it is also passed to the host (I have no clue how to prevent that)
  129.     gci *.txt | Write-Table -PassThru | Get-Item # Final intention: ... | Remove-Item
  130.     
  131.         Directory: C:\Users\Gebruiker\Downloads\temp
  132.     
  133.     Mode                 LastWriteTime         Length Name
  134.     ----                 -------------         ------ ----
  135.     -a---           7/20/2023  3:44 PM              0 file1.txt
  136.     Get-Item: Cannot find path &#39;Microsoft.PowerShell.Commands.Internal.Format.FormatStartData&#39; because it does not exist.
  137.     Get-Item: Cannot find path &#39;Microsoft.PowerShell.Commands.Internal.Format.GroupStartData&#39; because it does not exist.
  138.     Get-Item: Cannot find path &#39;Microsoft.PowerShell.Commands.Internal.Format.FormatEntryData&#39; because it does not exist.
  139.     -a---           7/20/2023  3:44 PM              0 file2.txt
  140.     Get-Item: Cannot find path &#39;Microsoft.PowerShell.Commands.Internal.Format.FormatEntryData&#39; because it does not exist.
  141.     -a---           7/20/2023  3:44 PM              0 file3.txt
  142.     Get-Item: Cannot find path &#39;Microsoft.PowerShell.Commands.Internal.Format.FormatEntryData&#39; because it does not exist.
  143.     Get-Item: Cannot find path &#39;Microsoft.PowerShell.Commands.Internal.Format.GroupEndData&#39; because it does not exist.
  144.     Get-Item: Cannot find path &#39;Microsoft.PowerShell.Commands.Internal.Format.FormatEndData&#39; because it does not exist.
  146. Does anyone have an explanation where this goes sideways and how I might resolve this?
  149. </details>
  152. # 答案1
  153. **得分**: 2
  155. 以下是您要翻译的部分：
  157. 看起来对包装的命令稍作更新应该能解决您的问题，如果我理解正确，`Format-Table` 生成的输出应该直接发送到主机，因此需要添加 `Out-Host`。然后，如果存在 `-PassThru`，您很可能希望将原始对象发送到管道中，因此：
  159. ```sh
  160. function Write-Table {
  161.     [CmdletBinding(HelpUri = 'https://go.microsoft.com/fwlink/?LinkID=2096703')]
  162.     param(
  163.         [switch]
  164.         ${AutoSize},
  166.         [switch]
  167.         ${RepeatHeader},
  169.         [switch]
  170.         ${HideTableHeaders},
  172.         [switch]
  173.         ${Wrap},
  175.         [Parameter(Position = 0)]
  176.         [System.Object[]]
  177.         ${Property},
  179.         [System.Object]
  180.         ${GroupBy},
  182.         [string]
  183.         ${View},
  185.         [switch]
  186.         ${ShowError},
  188.         [switch]
  189.         ${DisplayError},
  191.         [switch]
  192.         ${Force},
  194.         [ValidateSet('CoreOnly', 'EnumOnly', 'Both')]
  195.         [string]
  196.         ${Expand},
  198.         [Parameter(ValueFromPipeline = $true)]
  199.         [psobject]
  200.         ${InputObject},
  202.         [switch]
  203.         ${PassThru})
  205.     begin {
  206.         $null = $PSBoundParameters.Remove('PassThru')
  207.         $scriptCmd = { Microsoft.PowerShell.Utility\Format-Table @PSBoundParameters | Out-Host }
  208.         $steppablePipeline = $scriptCmd.GetSteppablePipeline($myInvocation.CommandOrigin)
  209.         $steppablePipeline.Begin($PSCmdlet)
  210.     }
  212.     process {
  213.         if ($PassThru.IsPresent) {
  214.             $InputObject
  215.         }
  217.         $steppablePipeline.Process($InputObject)
  218.     }
  220.     end {
  221.         $steppablePipeline.End()
  222.     }
  224.     clean {
  225.         if ($null -ne $steppablePipeline) {
  226.             $steppablePipeline.Clean()
  227.         }
  228.     }
  229.     &lt;#
  231.     .ForwardHelpTargetName Microsoft.PowerShell.Utility\Format-Table
  232.     .ForwardHelpCategory Cmdlet
  234.     #&gt;
  235. }

然后，类似这样的代码：

  1. $capture = 0..5 | ForEach-Object { [pscustomobject]@{ Item = $_ } } |
  2.     Write-Table -PassThru |
  3.     ForEach-Object Item

可以正常工作：

  1. PS ..\pwsh&gt; $capture = 0..10 | ForEach-Object { [pscustom....  # 输出发送到主机： Item ----    0    1    2    3    4    5
  2. PS ..\pwsh&gt; $capture
  3. 0
  4. 1
  5. 2
  6. 3
  7. 4
  8. 5
  9. 6
  10. 7
  11. 8
  12. 9
  13. 10
英文:

It seems a little update to the wrapped command should solve your problem if I'm understanding correctly, the output generated by Format-Table should go directly to the host, thus adding Out-Host. Then if -PassThru is present you more than likely want to send the original object thru the pipeline so:

  1. function Write-Table {
  2.     [CmdletBinding(HelpUri = &#39;https://go.microsoft.com/fwlink/?LinkID=2096703&#39;)]
  3.     param(
  4.         [switch]
  5.         ${AutoSize},
  7.         [switch]
  8.         ${RepeatHeader},
  10.         [switch]
  11.         ${HideTableHeaders},
  13.         [switch]
  14.         ${Wrap},
  16.         [Parameter(Position = 0)]
  17.         [System.Object[]]
  18.         ${Property},
  20.         [System.Object]
  21.         ${GroupBy},
  23.         [string]
  24.         ${View},
  26.         [switch]
  27.         ${ShowError},
  29.         [switch]
  30.         ${DisplayError},
  32.         [switch]
  33.         ${Force},
  35.         [ValidateSet(&#39;CoreOnly&#39;, &#39;EnumOnly&#39;, &#39;Both&#39;)]
  36.         [string]
  37.         ${Expand},
  39.         [Parameter(ValueFromPipeline = $true)]
  40.         [psobject]
  41.         ${InputObject},
  43.         [switch]
  44.         ${PassThru})
  46.     begin {
  47.         $null = $PSBoundParameters.Remove(&#39;PassThru&#39;)
  48.         $scriptCmd = { Microsoft.PowerShell.Utility\Format-Table @PSBoundParameters | Out-Host }
  49.         $steppablePipeline = $scriptCmd.GetSteppablePipeline($myInvocation.CommandOrigin)
  50.         $steppablePipeline.Begin($PSCmdlet)
  51.     }
  53.     process {
  54.         if ($PassThru.IsPresent) {
  55.             $InputObject
  56.         }
  58.         $steppablePipeline.Process($InputObject)
  59.     }
  61.     end {
  62.         $steppablePipeline.End()
  63.     }
  65.     clean {
  66.         if ($null -ne $steppablePipeline) {
  67.             $steppablePipeline.Clean()
  68.         }
  69.     }
  70.     &lt;#
  72.     .ForwardHelpTargetName Microsoft.PowerShell.Utility\Format-Table
  73.     .ForwardHelpCategory Cmdlet
  75.     #&gt;
  76. }

Then something like this:

  1. $capture = 0..5 | ForEach-Object { [pscustomobject]@{ Item = $_ } } |
  2.     Write-Table -PassThru |
  3.     ForEach-Object Item

Works just fine:

  1. PS ..\pwsh&gt; $capture = 0..10 | ForEach-Object { [pscustom....
  2. # Output sent to the host:
  3. Item
  4. ----
  5. 0
  6. 1
  7. 2
  8. 3
  9. 4
  10. 5
  11. PS ..\pwsh&gt; $capture
  12. 0
  13. 1
  14. 2
  15. 3
  16. 4
  17. 5
  18. 6
  19. 7
  20. 8
  21. 9
  22. 10

huangapple
  • 本文由 发表于 2023年7月20日 22:32:02
  • 转载请务必保留本文链接：https://go.coder-hub.com/76730959.html
  • command
  • powershell
  • proxy
  • tee
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