public/Resolve-DynamicFunctionDefinition.ps1
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$code = @' using System; using System.Collections.Generic; using System.Management.Automation; public class DynamicAttribute : System.Attribute { private ScriptBlock sb; public DynamicAttribute(ScriptBlock condition) { sb = condition; } } '@ $null = Add-Type -TypeDefinition $code *>&1 function Resolve-DynamicFunctionDefinition { <# .SYNOPSIS Generates a scriptblock defining an interpreted function based on the provided function info .DESCRIPTION Module adds a new attribute named [Dynamic()] that can be used to turn static parameters into dynamic parameters. The attribute definition will be defined above a standard parameter definition and must contain a scriptblock that evaluates truthiness. Resolve-DynamicFunctionDefinition will then interpret the [Dynamic(...)] attributes into standard PowerShell dynamic parameter declarations and return back a scriptblock with the new function definition. Example Dynamic Parameter Declaration: [Dynamic({$OtherParameter -match "(Value1|Value2)"})] [Parameter(Mandatory)] [string]$Name .INPUTS System.Management.Automation.FunctionInfo .OUTPUTS scriptblock .EXAMPLE Resolve-DynamicFunctionDefinition -FunctionInfo Value Evaluates function definition for dynamic parameters and returns a new scriptblock containing a function definition to properly handle the defined dynamic parameters .NOTES Inspired in large part by Dr. Tobias Weltner (https://github.com/TobiasPSP/) and his amazing work at https://powershell.one/ #> [CmdletBinding()] param ( # FunctionInfo object for the function to evaluate and process for parameters with the [Dynamic()] attribute [Parameter(Mandatory, ValueFromPipeline)] [System.Management.Automation.FunctionInfo]$FunctionInfo, # Forces functions missing the [CmdletBinding()] attribute, to be interpreted as advanced functions [Parameter()] [switch]$Force ) process { try { # This is the object that we will use to build up the new function definition $result = New-Object -TypeName System.Text.StringBuilder # Store dynamic parameter default values $defaultValues = @{} # Store list of dynamic parameters $dynParamList = [System.Collections.ObjectModel.Collection[string]]::new() # Store list of static parameters $paramList = [System.Collections.ObjectModel.Collection[string]]::new() # Store list of non-pipeline bound parameters $standardParamList = [System.Collections.ObjectModel.Collection[string]]::new() # If function does not contain cmdlet binding, return the original definition if (Assert-DynamicFunctionIsAdvanced -FunctionInfo $FunctionInfo) { $null = $result.AppendLine("function $($FunctionInfo.Name) {") } else { if (-not $Force) { Write-Warning "$($FunctionInfo.Name) is not an advanced function, using original function content" return Resolve-DynamicSimpleFunction -FunctionInfo $FunctionInfo } else { $null = $result.AppendLine("function $($FunctionInfo.Name) {") $null = $result.AppendLine(" [CmdletBinding()]") } } $paramBlockAst = Get-DynamicFunctionParamBlockContent -FunctionInfo $FunctionInfo Add-DynamicFunctionAttribute -StringBuilder $result -ParamBlockAst $paramBlockAst # Add a placeholder that will be replaced after processing for [Dynamic()] tagged parameters Add-DynamicFunctionParamBlockPlaceholder -StringBuilder $result $dynamicParameters = $paramBlockAst.Parameters | Get-DynamicFunctionParameter -Type 'dynamic' $staticParameters = $paramBlockAst.Parameters | Get-DynamicFunctionParameter -Type 'static' if ($dynamicParameters) { $dynamicParameters | Add-DynamicFunctionDynamicParamBlock -StringBuilder $result -DefaultValueTable $defaultValues foreach ($dynamicParameter in $dynamicParameters) { $parameterName = $dynamicParameter.Name.VariablePath.UserPath $dynParamList.Add($parameterName) } $pipelineParamList = $dynamicParameters | Get-DynamicFunctionPipelineParameterName } if ($staticParameters) { foreach ($staticParameter in $staticParameters) { $paramList.Add($staticParameter.Extent.Text) } } $dynParamList | ForEach-Object { $dynParam = $_ if ($dynParam -notin $pipelineParamList) { $null = $standardParamList.Add($dynParam) } } $beginBlockContent = Get-DynamicFunctionScriptBlockContent -Name begin -FunctionInfo $FunctionInfo $needsBeginBlock = $dynParamList.Count -or -not [string]::IsNullOrWhiteSpace($beginBlockContent) if ($needsBeginBlock) { Add-DynamicFunctionScriptBlock -StringBuilder $result -Name begin -Content $beginBlockContent -Parameter $dynParamList -DefaultValueTable $defaultValues } $processBlockContent = Get-DynamicFunctionScriptBlockContent -Name process -FunctionInfo $FunctionInfo $needsProcessBlock = -not [string]::IsNullOrWhiteSpace($processBlockContent) -or $pipelineParamList.Count if ($needsProcessBlock) { Add-DynamicFunctionScriptBlock -StringBuilder $result -Name process -Content $processBlockContent -Parameter $pipelineParamList } $endBlockContent = Get-DynamicFunctionScriptBlockContent -Name end -FunctionInfo $FunctionInfo if (-not [string]::IsNullOrWhiteSpace($endBlockContent)) { Add-DynamicFunctionScriptBlock -StringBuilder $result -Name end -Content $endBlockContent } # Add the function block's closing brace $null = $result.Append('}') Set-DynamicFunctionParamBlockPlaceholder -StringBuilder $result -ParameterList $paramList Test-DynamicFunctionDefinition -Definition $result } catch { $PSCmdlet.ThrowTerminatingError($_) } } } |