Functions/Expand-Template.ps1
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function Expand-Template { <# .SYNOPSIS Expand-Template.ps1 Simple templating engine to expand a given template text containing PowerShell expressions. .EXAMPLE $text="hello"; .\Expand-Template.ps1 -Text 'Hello [[$text]] world' #> [CmdletBinding()] param ( [Parameter(Mandatory=$false, ParameterSetName='Text',ValueFromPipeline=$true)] #The text of the template to do the expansion [string]$Text, [Parameter(Mandatory=$true, ParameterSetName='Path')] #Path to template to do the expansion [string]$Path, #Destination path to write expansion result. If not specified, write to output stream. [string]$Destination, #Path to file containing JSON template property values [string[]]$ConfigJsonPath, #Begin tag for detecting expand expression in template, default is '[[' [string]$BeginTag = '[[', #End tag for detecting expand expression in template, default is ']]' [string]$EndTag = ']]', [ref]$TotalExpansions, [string]$ContentMatchRegEx = '.*?', [string]$ReplacementExpression ) if($TotalExpansions) { $TotalExpansions.Value = 0 } $BeginTag = [RegEx]::Escape($BeginTag) $EndTag = [RegEx]::Escape($EndTag) $encoding = 'UTF8' Write-Verbose "Expand-Template: $Path" if ($Path) { if (!(Test-Path -LiteralPath $path )) { throw "Template-Expand: path `'$path`' can't be found" } $Text = Get-Content -LiteralPath $path -Raw $encoding = Get-FileEncoding -Path $path } if(-not $text) { Write-Verbose 'WARNING: No text to replace $Path' return; } #Load the configuration if ($ConfigJsonPath) { if (!(Test-Path -Path $ConfigJsonPath)) { throw "Replace-AllTemplateFiles: JSON configuration file(s) `'$ConfigJsonPath`' can't be found" } Write-Verbose "Loading JSON Configuration file: $ConfigJsonPath" Import-TemplateConfiguration -Path $ConfigJsonPath } if($TotalExpansions) { $global:expansionCount = $TotalExpansions.Value } else { $global:expansionCount = 0 } $pattern = New-Object -Type System.Text.RegularExpressions.Regex ` -ArgumentList "$BeginTag($ContentMatchRegEx)$EndTag",([System.Text.RegularExpressions.RegexOptions]::Singleline -bor [System.Text.RegularExpressions.RegexOptions]::IgnoreCase) $matchEvaluatorDelegate = [System.Text.RegularExpressions.MatchEvaluator] { param([System.Text.RegularExpressions.Match]$Match) $expression = $ReplacementExpression if(-not $expression) { $expression = $match.get_Groups()[1].Value # content between markers } trap { Write-Error "Failed to expand template. Can't evaluate expression '$expression'. The following error occured: $_"; break } $global:expansionCount++ $numReplaced = $global:expansionCount #Perform expansion on the values too $expression = $expression -replace '\\"','"' Write-Verbose "`texpanding expression: $expression" Invoke-Expression -command "Write-output ($expression)" | Expand-Template -TotalExpansions ([ref]$global:expansionCount) | Tee-Object -Variable result Write-Verbose "`texpanded expression evaluated value:`n$result`n" $global:expansionCount += $numReplaced } $expandedText = $pattern.Replace($text, $matchEvaluatorDelegate) if (-not $destination){ $expandedText } elseif($expandedText -ne $text -or $Destination -notlike $path) { $expandedText | Out-File -LiteralPath $destination -Encoding $encoding -Force -NoNewline } if($Destination -and -not (Test-Path $Destination)) { throw "Expected file $Destination to exist, but it does not" } if($TotalExpansions) { $TotalExpansions.Value += $global:expansionCount } } |