Public/System/Get-CallerPreference.ps1
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#requires -Version 2.0 function Get-CallerPreference { <# .Synopsis Fetches "Preference" variable values from the caller's scope. .DESCRIPTION Script module functions do not automatically inherit their caller's variables, but they can be obtained through the $PSCmdlet variable in Advanced Functions. This function is a helper function for any script module Advanced Function; by passing in the values of $ExecutionContext.SessionState and $PSCmdlet, Get-CallerPreference will set the caller's preference variables locally. .PARAMETER Cmdlet The $PSCmdlet object from a script module Advanced Function. .PARAMETER SessionState The $ExecutionContext.SessionState object from a script module Advanced Function. This is how the Get-CallerPreference function sets variables in its callers' scope, even if that caller is in a different script module. .PARAMETER Name Optional array of parameter names to retrieve from the caller's scope. Default is to retrieve all Preference variables as defined in the about_Preference_Variables help file (as of PowerShell 4.0) This parameter may also specify names of variables that are not in the about_Preference_Variables help file, and the function will retrieve and set those as well. .EXAMPLE Get-CallerPreference -Cmdlet $PSCmdlet -SessionState $ExecutionContext.SessionState Imports the default PowerShell preference variables from the caller into the local scope. .EXAMPLE Get-CallerPreference -Cmdlet $PSCmdlet -SessionState $ExecutionContext.SessionState -Name 'ErrorActionPreference','SomeOtherVariable' Imports only the ErrorActionPreference and SomeOtherVariable variables into the local scope. .EXAMPLE 'ErrorActionPreference','SomeOtherVariable' | Get-CallerPreference -Cmdlet $PSCmdlet -SessionState $ExecutionContext.SessionState Same as Example 2, but sends variable names to the Name parameter via pipeline input. .INPUTS String .OUTPUTS None. This function does not produce pipeline output. .LINK about_Preference_Variables #> [CmdletBinding(DefaultParameterSetName = 'AllVariables')] param ( [Parameter(Mandatory = $true)] [ValidateScript({ $_.GetType().FullName -eq 'System.Management.Automation.PSScriptCmdlet' })] $Cmdlet, [Parameter(Mandatory = $true)] [System.Management.Automation.SessionState] $SessionState, [Parameter(ParameterSetName = 'Filtered', ValueFromPipeline = $true)] [string[]] $Name ) begin { $filterHash = @{} } process { if ($null -ne $Name) { foreach ($string in $Name) { $filterHash[$string] = $true } } } end { # List of preference variables taken from the about_Preference_Variables help file in PowerShell version 4.0 $vars = @{ 'ErrorView' = $null 'FormatEnumerationLimit' = $null 'LogCommandHealthEvent' = $null 'LogCommandLifecycleEvent' = $null 'LogEngineHealthEvent' = $null 'LogEngineLifecycleEvent' = $null 'LogProviderHealthEvent' = $null 'LogProviderLifecycleEvent' = $null 'MaximumAliasCount' = $null 'MaximumDriveCount' = $null 'MaximumErrorCount' = $null 'MaximumFunctionCount' = $null 'MaximumHistoryCount' = $null 'MaximumVariableCount' = $null 'OFS' = $null 'OutputEncoding' = $null 'ProgressPreference' = $null 'PSDefaultParameterValues' = $null 'PSEmailServer' = $null 'PSModuleAutoLoadingPreference' = $null 'PSSessionApplicationName' = $null 'PSSessionConfigurationName' = $null 'PSSessionOption' = $null 'ErrorActionPreference' = 'ErrorAction' 'DebugPreference' = 'Debug' 'ConfirmPreference' = 'Confirm' 'WhatIfPreference' = 'WhatIf' 'VerbosePreference' = 'Verbose' 'WarningPreference' = 'WarningAction' } foreach ($entry in $vars.GetEnumerator()) { if (([string]::IsNullOrEmpty($entry.Value) -or -not $Cmdlet.MyInvocation.BoundParameters.ContainsKey($entry.Value)) -and ($PSCmdlet.ParameterSetName -eq 'AllVariables' -or $filterHash.ContainsKey($entry.Name))) { $variable = $Cmdlet.SessionState.PSVariable.Get($entry.Key) if ($null -ne $variable) { if ($SessionState -eq $ExecutionContext.SessionState) { Set-Variable -Scope 1 -Name $variable.Name -Value $variable.Value -Force -Confirm:$false -WhatIf:$false } else { $SessionState.PSVariable.Set($variable.Name, $variable.Value) } } } } if ($PSCmdlet.ParameterSetName -eq 'Filtered') { foreach ($varName in $filterHash.Keys) { if (-not $vars.ContainsKey($varName)) { $variable = $Cmdlet.SessionState.PSVariable.Get($varName) if ($null -ne $variable) { if ($SessionState -eq $ExecutionContext.SessionState) { Set-Variable -Scope 1 -Name $variable.Name -Value $variable.Value -Force -Confirm:$false -WhatIf:$false } else { $SessionState.PSVariable.Set($variable.Name, $variable.Value) } } } } } } # end } # function Get-CallerPreference |