Out-Splat.ps1
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function Out-Splat { <# .Synopsis Outputs code that splats .Description Outputs a function or script that primarily calls another command. This can get messy to write by hand. .Link Initialize-Splatter .Example Out-Splat -CommandName Get-Command #> [CmdletBinding(DefaultParameterSetName='JustTheSplatter')] [OutputType([ScriptBlock])] param( # The name of the command that will be splatted [Parameter(Mandatory=$true,Position=0,ValueFromPipelineByPropertyName)] [Alias('Name')] [string] $CommandName, # A hashtable of default parameters. These will always be passed to the underlying command by name. [Parameter(Position=1,ValueFromPipelineByPropertyName)] [Alias('DefaultParameters')] [Hashtable] $DefaultParameter = @{}, # A list of arguments. These will be always be passed to the underlying commands by position. # Items starting with $ will be treated as a variable. [Parameter(ValueFromPipelineByPropertyName)] [string[]] $ArgumentList, # A list of parameters names that will be inputted from the original command into the splat. # If generating a function, these parameter declarations will be copied from the underlying command. # Help for these parameters will be included as comment-based help [Parameter(Position=3,ValueFromPipelineByPropertyName)] [Alias('IncludeParameter')] [string[]] $InputParameter, # A list of parameters that will be excluded from the original function. # This is only valid when generating a function. # Wildcards may be used. [Parameter(Position=4,ValueFromPipelineByPropertyName)] [string[]] $ExcludeParameter, # If set, values from input parameters will override default values. [Alias('OverrideDefault','OverwriteDefault', 'DefaultOverwrite')] [Parameter(ValueFromPipelineByPropertyName)] [Switch] $DefaultOverride, # If set, any variable with a non-null value matching the input parameters will be used to splat. # If not set, only bound parameters will be used to splat. # If no function name is provided, this will automatically be set [Parameter(ValueFromPipelineByPropertyName)] [Switch] $VariableInput, # The name of the variable used to hold the splatted parameters. By default, ${CommandName}Parameters (e.g. GetHelpP [Parameter(ValueFromPipelineByPropertyName)] [Alias('SplatName')] [string] $VariableName, # An optional name of a generated function. # If provided, this function will declare any input parameters specified in -InputParameter [Parameter(Mandatory=$true,Position=2,ValueFromPipelineByPropertyName,ParameterSetName='FunctionalSplatter')] [string] $FunctionName, # The synopsis. # This is used to make comment-based help in a generated function. # By default, it is : "Wraps $CommandName" [Parameter(ValueFromPipelineByPropertyName,ParameterSetName='FunctionalSplatter')] [string] $Synopsis, # The description. # This is used to make comment-based help in a generated function. [Parameter(ValueFromPipelineByPropertyName,ParameterSetName='FunctionalSplatter')] [string] $Description, # The CmdletBinding attribute for a new function [Parameter(ValueFromPipelineByPropertyName,ParameterSetName='FunctionalSplatter')] [string] $CmdletBinding, # A set of additional parameter declarations. # The keys are the names of the parameters, and the values can be a type and a string containing parameter binding and inline help. [Parameter(ValueFromPipelineByPropertyName,ParameterSetName='FunctionalSplatter')] [Hashtable] $AdditionalParameter, # The serialization depth for default parameters. By default, 2. [uint32] $SerializationDepth = 2, # If set, will generate the code to collect the -CommandName input as dynamic parameters. [Parameter(Mandatory,ParameterSetName='DynamicSplatter')] [Alias('DynamicParameters')] [switch] $DynamicParameter, # If set, will not allow dynamic parameters to use ValueFromPipeline or ValueFromPipelineByPropertyName [Parameter(ParameterSetName='DynamicSplatter')] [switch] $Unpiped, # If provided, will offset the position of any positional parameters. [Parameter(ParameterSetName='DynamicSplatter')] [int] $Offset, # If provided, dynamic parameters will be created in a new parameter set, named $NewParameterSetName. [Parameter(ParameterSetName='DynamicSplatter')] [string] $NewParameterSetName, # If set, will cross errors into the output stream. # You SHOULD cross the streams when dealing with console applications, as many of them like to return output on standard error. [Parameter(ValueFromPipelineByPropertyName)] [Switch] $CrossStream, # A script block used to filter the results [ScriptBlock]$Where, # A script to run before the splatter starts [ScriptBlock]$Begin, # A script to run on each splatter result [ScriptBlock]$Process, # A script to run after the splat is over [ScriptBlock]$End, # If provided, will pipe directly into the contents of this script block. # This assumes that the first item in the script block is a command, and it will accept the output of the splat as pipelined input [ScriptBlock] [Alias('PipeInto','Pipe')] $PipeTo) process { # First, let's find the command. $commandExists = $ExecutionContext.SessionState.InvokeCommand.GetCommand($CommandName, 'All') if (-not $commandExists) { # If we don't, error out. Write-Error "$CommandName does not exist" return } if ($InputParameter.Count -eq 1 -and $InputParameter -eq '*') { if ($commandExists -is [Management.Automation.ApplicationInfo]) { $InputParameter = @() } else { $InputParameter = ($commandExists -as [Management.Automation.CommandMetaData]).Parameters.Keys } } if ($DynamicParameter) { if (-not $VariableName) { # If no -VariableName was provided, $VariableName = "$($CommandName -replace '[\W\s]','')DynamicParameters" # default to ${CommandName}DynamicParameters } $safeCommandName = $($CommandName -replace '[\W\s]','') return [ScriptBlock]::Create(@( "if (-not `$$VariableName) { `$$VariableName = [Management.Automation.RuntimeDefinedParameterDictionary]::new()" " `$$($CommandName -replace '[\W\s]','') = `$executionContext.SessionState.InvokeCommand.GetCommand('$CommandName', 'All')" $inputForeach = if ($InputParameter) { "'$(@(:nextInputParameter foreach ($in in $InputParameter) { foreach ($ex in $ExcludeParameter) { if ($in -like $ex) { continue nextInputParameter } } $in }) -join "','")'" } else { "([Management.Automation.CommandMetaData]`$$safeCommandName).Parameters.Keys" } " :nextInputParameter foreach (`$in in $inputForeach) { $(if ($ExcludeParameter) { "foreach (`$ex in '$($ExcludeParameter -join "','")') { if (`$in -like `$ex) { continue nextInputParameter } } "}) `$$variableName.Add(`$in, [Management.Automation.RuntimeDefinedParameter]::new( `$$SafeCommandName.Parameters[`$in].Name, `$$SafeCommandName.Parameters[`$in].ParameterType, `$$SafeCommandName.Parameters[`$in].Attributes )) }" if ($Unpiped -or $Offset -or $NewParameterSetName) { " foreach (`$paramName in `$$variableName.Keys) { foreach (`$attr in `$$variableName[`$paramName].Attributes) { $(@( if ($Unpiped) { ' if ($attr.ValueFromPipeline) {$attr.ValueFromPipeline = $false}' ' if ($attr.ValueFromPipelineByPropertyName) {$attr.ValueFromPipelineByPropertyName = $false}' } if ($Offset) { " if (`$attr.Position -ge 0) { `$attr.Position += $offset }" } if ($NewParameterSetName) { " if (`$attr.psobject.properties('ParameterSetName')) { `$attr.ParameterSetName = '$NewParameterSetName' }" } ) -join [Environment]::NewLine) } }" } '}' "`$$variableName" ) -join [Environment]::NewLine) } if (-not $VariableName) { # Next, if no -VariableName was provided, $VariableName = "$($CommandName -replace '[\W\s]','')Parameters" } $defaultDeclaration = if ($DefaultParameter.Count) { $toSplat = "@' $(ConvertTo-Json $DefaultParameter -Depth $SerializationDepth) '@" "`$${VariableName}Default = ConvertFrom-Json $toSplat" "`$$VariableName = @{}" "foreach (`$property in `$${VariableName}Default.psobject.properties) { `$$VariableName[`$property.Name] = `$property.Value if (`$property.Value -is [string] -and `$property.Value.StartsWith('`$')) { `$$VariableName[`$property.Name] = `$executionContext.SessionState.PSVariable.Get(`$property.Value.Substring(1)).Value } }" } elseif ($ArgumentList.Count) { "`$$VariableName = " + @(foreach ($a in $ArgumentList) { if ($a.StartsWith('$')) { $a } else { "'$($a.Replace("'","''"))'" } }) -join ',' } else { "`$$VariableName = @{}" } if (-not $FunctionName) { $VariableInput = $true } $paramSplat = if ($InputParameter -or $FunctionName) { if ($VariableInput) { " #region Copy Parameters from $CommandName foreach (`$in in '$($inputParameter -join "','")') { `$var = `$executionContext.SessionState.PSVariable.Get(`$in) if (-not `$var) { continue } $(if ($DefaultOverride) { "`$$VariableName.`$in = `$var.Value" } else { "`$$VariableName.`$in = `$var.Value" }) } #endregion Copy Parameters from $CommandName " } else { "#region Copy Parameters from $CommandName `$MyParameters = [Ordered]@{} + `$psBoundParameters # Copy `$PSBoundParameters foreach (`$in in $(if ($inputParameter) { "'$($inputParameter -join "','")'" } else { "`$MyParameters.Keys`"})) { $(if ($DefaultOverride) { "if (`$myParameters.`$in) { `$$VariableName.`$in = `$myParameters.`$in }" } else { "if (-not `$$VariableName.`$in -and `$myParameters.`$in) { `$$VariableName.`$in = `$myParameters.`$in }"}) } #endregion Copy Parameters from $CommandName " } } else { @() } $paramSplat = $paramSplat -join ([Environment]::NewLine) $cmdDef = if ([Management.Automation.ExternalScriptInfo],[Management.Automation.ApplicationInfo] -contains $commandExists.GetType()) { " & '$($commandExists.Source.Replace("'","''"))' @$VariableName" } else { "$commandExists @$VariableName" } if ($CrossStream) { $cmdDef += " *>&1" } if ($Where) { $cmdDef += " | Where-Object {$Where}" } if ($PipeTo) { $cmdDef += "| $PipeTo" } if ($Begin -or $Process -or $End) { $cmdDef += " | Foreach-Object$(if ($Begin) { " -Begin { $Begin }"})$(if ($Process) { " -Process { $Process }"})$(if ($End) { " -End { $end }"})" } $coreSplat = (@() + $defaultDeclaration + $paramSplat + $cmdDef) -join ([Environment]::NewLine) if ($FunctionName) { $commandMeta = $commandExists -as [Management.Automation.CommandMetadata] foreach ($k in @($commandMeta.Parameters.Keys)) { if ($InputParameter -notcontains $k) { $null =$commandMeta.Parameters.Remove($k) } } $originalCmdletBinding = [Management.Automation.Proxycommand]::GetCmdletBindingAttribute($commandExists) $cmdHelp = Get-Help -Name $commandExists if ($cmdHelp -is [string]) { $cmdHelp = $null } $paramBlock = [Management.Automation.Proxycommand]::GetParamBlock($commandExists) -replace '\{(\S{1,})\}', '$1' $paramParts = $paramBlock -split ',\W{1,}[\[$]' -ne '' $paramBlockParts = @(foreach ($param in $paramParts) { $lastDollar = $param.LastIndexOf('$') $parameterName = $param.Substring($lastDollar + 1).Trim() $parameterHelp = if ($cmdHelp) { $cmdHelp.parameters[0].parameter | Where-Object { $_.Name -eq $parameterName -and $_.Description }| Select-Object -ExpandProperty Description | Select-Object -ExpandProperty Text } else { $null } $param = $param.Trim() if (-not $param.StartsWith('$') -and -not $param.StartsWith('[')) { $param = "[$param" } if ($ExcludeParameter) { $shouldExclude = foreach ($ex in $ExcludeParameter) { if ($parameterName -like "$ex") { $true break } } if ($shouldExclude) { continue } } if ($parameterHelp) { $lines = "$parameterHelp".Split("`r`n",[StringSplitOptions]'RemoveEmptyEntries') if ($lines.Count -lt 8) { (@(foreach ($l in $lines) { " #$l" }) -join ([Environment]::NewLine)) + ([Environment]::NewLine) + (' '*4) + $param } else { " <# $parameterHelp #> $param" } } else { $param } }) if ($AdditionalParameter) { foreach ($kv in $AdditionalParameter.GetEnumerator()) { $varName = if ($kv.Key.StartsWith('$')) { $kv.Key } else { '$' + $kv.Key } $newParamBlockPart = if ($kv.Value -is [type]) { if ($kv.Value.FullName -like "System.*") { " [$($kv.Value.Fullname.Substring(7))]$varName" } elseif ($kv.Value -eq [switch]) { " [switch]$varName" } else { " [$($kv.Value.Fullname)]$varName" } } elseif ($kv.Value -is [string]) { $varDeclared = $false $newLines = foreach ($line in $kv.Value -split [Environment]::NewLine) { $trimLine = $Line.Trim() if ($trimLine.StartsWith('[')) { if ($trimLine -like $varName) { $varDeclared = $true } (' ' * 4) + $trimLine } # It's an attribute! elseif ($trimLine.StartsWith('$')) { # It's a variable! $varDeclared = $true (' ' * 4) + $trimLine } elseif ($trimLine.StartsWith('#')) { # It's a comment! (' ' * 4) + $trimLine } else { # Otherwise, we'll treat it like a comment anyways (' ' * 4) + '#' + $trimLine } } if (-not $varDeclared) { $newLines += (' ' * 4) + $varName } $newLines -join ([Environment]::NewLine) } elseif ($kv.Value -is [Object[]]) { } if ($newParamBlockPart) { $paramBlockParts += $newParamBlockPart } } } $paramBlock = $paramBlockParts -join (',' + ([Environment]::NewLine * 2)) if (-not $Synopsis) { $Synopsis = "Wraps $CommandName" } if (-not $Description) { $Description = "Calls $CommandName, using splatting" } [ScriptBlock]::Create("function $FunctionName { <# .Synopsis $Synopsis .Description $Description .Link $CommandName #>$(if ($CmdletBinding) { if ($CmdletBinding -like "*CmdletBinding*") { [Environment]::NewLine + (' '*4) + $CmdletBinding } else { [Environment]::NewLine + (' '*4) + "[CmdletBinding($CmdletBinding)]" } } elseif ($originalCmdletBinding) { [Environment]::NewLine + (' '*4) + $originalCmdletBinding }) param( $paramBlock) process { $(@(foreach ($line in $coreSplat -split ([Environment]::Newline)) { if ($line.StartsWith("'@")) { $line } else { (' ' * 8) + $line } }) -join ([Environment]::NewLine)) } } ") } else { [ScriptBlock]::Create($coreSplat) } } } |