隐藏Invoke-WebRequest的进度

Question

如何隐藏进度显示Invoke-WebRequest？我做了很多连续的请求并拥有自己的Write-Progress显示器,所以我不需要每次都在它下面弹出一个内置的显示器.

我使用从Invoke-WebRequest自动结果创建的mshtml结果(IE COM对象),因此我无法切换到WebClient类似的东西,除非有人提供有关如何从WebClient请求获取mshtml对象的说明.

Answer 1

使用$ progressPreference变量.默认情况下,它应该具有"继续"值,除非您已在其他位置编辑它,这告诉Powershell显示进度条.由于您提到您有自己的自定义进度显示,因此我会在执行cmdlet后立即重置它.例如:

$progressPreference = 'silentlyContinue'    # Subsequent calls do not display UI.
Invoke-WebRequest ...
$progressPreference = 'Continue'            # Subsequent calls do display UI.
Write-Progress ...

有关about_preference_variables上的首选项变量的更多信息.这是$ ProgressPreference的条目:

$ProgressPreference
-------------------
Determines how Windows PowerShell responds to progress updates 
        generated by a script, cmdlet or provider, such as the progress bars
        generated by the Write-Progress cmdlet. The Write-Progress cmdlet 
        creates progress bars that depict the status of a command.

        Valid values:
          Stop:               Does not display the progress bar. Instead,
                                it displays an error message and stops executing.

          Inquire:            Does not display the progress bar. Prompts
                                for permission to continue. If you reply
                                with Y or A, it displays the progress bar.

          Continue:           Displays the progress bar and continues with
          (Default)             execution.

          SilentlyContinue:   Executes the command, but does not display
                                the progress bar.

Answer 2

这是一个可重用的函数，可以暂时隐藏任何脚本块的进度，并在脚本块结束时自动恢复进度首选项，即使脚本块抛出异常（脚本终止错误）也是如此。

# Create an in-memory module so $ScriptBlock doesn't run in new scope
$null = New-Module {
    function Invoke-WithoutProgress {
        [CmdletBinding()]
        param (
            [Parameter(Mandatory)] [scriptblock] $ScriptBlock
        )

        # Save current progress preference and hide the progress
        $prevProgressPreference = $global:ProgressPreference
        $global:ProgressPreference = 'SilentlyContinue'

        try {
            # Run the script block in the scope of the caller of this module function
            . $ScriptBlock
        }
        finally {
            # Restore the original behavior
            $global:ProgressPreference = $prevProgressPreference
        }
    }
}

使用示例：

Invoke-WithoutProgress {
    # Here $ProgressPreference is set to 'SilentlyContinue'
    Invoke-WebRequest ...
}

# Now $ProgressPreference is restored
Write-Progress ...

笔记：

• 该New-Module调用在那里，因此传递给的脚本块Invoke-WithoutProgress 不会在新范围中运行（允许它直接修改周围的变量，类似于 的ForEach-Object脚本块）。请参阅此答案以获取更多信息。