Private/Utils/Get-StructurePattern.ps1
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Function Get-StructurePattern { <# .SYNOPSIS Analyzes the structure of complex objects to create a pattern description. .DESCRIPTION This function recursively analyzes PowerShell objects (hashtables, PSCustomObjects, arrays) to create a comprehensive pattern description that can be used to generate similar test data. It identifies object types, property structures, array characteristics, and applies preservation rules for specified field patterns. The function handles infinite recursion prevention through depth limiting and provides detailed analysis of nested structures including arrays with item patterns and objects with property patterns. .PARAMETER Object The object to analyze. Can be hashtables, PSCustomObjects, arrays, or simple values. .PARAMETER Depth Current recursion depth. Used internally for infinite recursion prevention. Default value is 0. .PARAMETER MaxDepth Maximum allowed recursion depth. When exceeded, returns a fallback pattern. Default value is 10. .PARAMETER FieldPath Current field path in dot notation. Used internally for building hierarchical field paths and applying preservation patterns. .PARAMETER PreservePatterns Array of field path patterns that should be marked for preservation. Supports wildcard patterns for matching multiple fields. .OUTPUTS [hashtable] Returns a hashtable describing the structure: - For objects: Type, ObjectType, Properties (nested patterns) - For arrays: Type, ItemCount, SampleSize, ItemPatterns - For simple values: Delegates to Get-ValuePattern .EXAMPLE $obj = @{name = "John"; age = 30} Get-StructurePattern -Object $obj -PreservePatterns @() Returns pattern describing hashtable with string and integer properties .EXAMPLE $arr = @("item1", "item2", "item3") Get-StructurePattern -Object $arr -PreservePatterns @() Returns pattern describing array with string item patterns .EXAMPLE $obj = @{apiVersion = "v1"; data = "sensitive"} Get-StructurePattern -Object $obj -PreservePatterns @("apiVersion") Returns pattern with apiVersion marked for preservation .NOTES This is an internal utility function used by the PSTestableData module for analyzing complex data structures. It limits array analysis to the first 3 items for performance while maintaining representative patterns. #> [CmdletBinding()] [OutputType([hashtable])] Param( [object]$Object, [int]$Depth = 0, [int]$MaxDepth = 10, [string]$FieldPath = "", [string[]]$PreservePatterns = @() ) # Prevent infinite recursion if ($Depth -gt $MaxDepth) { return @{ Type = 'string'; Pattern = 'text'; Length = 10 } } if ($null -eq $Object) { return @{ Type = 'null' } } $type = $Object.GetType() if ($Object -is [hashtable] -or $Object -is [PSCustomObject]) { # Object pattern - handle this first before IEnumerable check $properties = @{} if ($Object -is [hashtable]) { foreach ($key in $Object.Keys) { $childPath = if ($FieldPath) { "$FieldPath.$key" } else { $key } $properties[$key] = Get-StructurePattern -Object $Object[$key] -Depth ($Depth + 1) -MaxDepth $MaxDepth -FieldPath $childPath -PreservePatterns $PreservePatterns } } else { foreach ($prop in $Object.PSObject.Properties) { $childPath = if ($FieldPath) { "$FieldPath.$($prop.Name)" } else { $prop.Name } $properties[$prop.Name] = Get-StructurePattern -Object $prop.Value -Depth ($Depth + 1) -MaxDepth $MaxDepth -FieldPath $childPath -PreservePatterns $PreservePatterns } } return @{ Type = 'object' Properties = $properties ObjectType = if ($Object -is [hashtable]) { 'hashtable' } else { 'pscustomobject' } } } elseif ($type.IsArray -or ($Object -is [System.Collections.IEnumerable] -and $Object -isnot [string] -and $Object -isnot [hashtable] -and $Object -isnot [PSCustomObject])) { # Array pattern - limit analysis to first 3 items to prevent excessive processing $items = @($Object) $itemPatterns = @() $maxItems = [math]::Min($items.Count, 3) for ($i = 0; $i -lt $maxItems; $i++) { $item = $items[$i] if ($item -is [hashtable] -or $item -is [PSCustomObject]) { # Use wildcard notation for array items to enable pattern matching like "items.*.apiVersion" or "*.kind" $arrayItemPath = if ($FieldPath) { "$FieldPath.*" } else { "*" } $itemPatterns += Get-StructurePattern -Object $item -Depth ($Depth + 1) -MaxDepth $MaxDepth -FieldPath $arrayItemPath -PreservePatterns $PreservePatterns } else { $pattern = Get-ValuePattern -Value $item # Use wildcard notation for array item values too $arrayItemPath = if ($FieldPath) { "$FieldPath.*" } else { "*" } $pattern.PreserveField = Test-PreserveField -FieldPath $arrayItemPath -PreservePatterns $PreservePatterns # Store original value if field should be preserved if ($pattern.PreserveField) { $pattern.OriginalValue = $item } $itemPatterns += $pattern } } return @{ Type = 'array' ItemCount = $items.Count ItemPatterns = $itemPatterns SampleSize = $maxItems } } else { # Primitive value $pattern = Get-ValuePattern -Value $Object # Mark if this field should be preserved from anonymization $pattern.PreserveField = Test-PreserveField -FieldPath $FieldPath -PreservePatterns $PreservePatterns # Store original value if field should be preserved if ($pattern.PreserveField) { $pattern.OriginalValue = $Object } return $pattern } } |