Helpers for merging JSON / PSCustomObject

- For instance, take a stock file and merge in a partial JSON file, filling in the differences - Handles merging arrays of strings, sorting and removing dupes - Handles merging named primitive values over - Handles merging together two simple key/value pair maps - Handles merging an array of simple key/value pair maps - Can convert ConvertTo-Json's hideous Unicode escaping to real chars - Provides a workaround for a PS3 bug where JSON strings cannot contain " characters https://connect.microsoft.com/PowerShell/feedback/details/735978/convertto-json-in-psv3-beta-does-not-support-values-containing-double-quotes
2013-03-07 20:43:18 -05:00
parent 03d686432d
commit a96bf479f8
1 changed files with 186 additions and 0 deletions
--- a/core/JsonHelpers.ps1
+++ b/core/JsonHelpers.ps1
@@ -0,0 +1,186 @@
+function ConvertFrom-UnicodeEscaped
+{
+  [CmdletBinding()]
+  param(
+    [Parameter(ValueFromPipeline=$true, Mandatory = $true)]
+    [String]
+    $Text
+  )
+
+  $regex = [regex]'\\[uU]([0-9A-Fa-f]{4})'
+  $callback = {
+    $match = $args[0]
+    $hexStyle = [Globalization.NumberStyles]::HexNumber
+    ([Char][Int32]::Parse($match.Value.Substring(2), $hexStyle)).ToString()
+  }
+
+  $regex.Replace($Text, $callback)
+}
+
+# HACK: this *must* be called after a file has been merged together to sanitize it
+function ConvertTo-DoubleEscapedQuotes
+{
+  [CmdletBinding()]
+  param(
+    [Parameter(ValueFromPipeline=$true, Mandatory = $true)]
+    [String]
+    $Text,
+
+    [Parameter(ValueFromPipeline=$true, Mandatory = $false)]
+    [String]
+    $Name = ''
+  )
+
+  # HACK: stupid powershell has a bug and doesn't allow " in JSON values
+  # So we're forced to double it up... which might not always work.. sigh
+  # If we try to get sneaky it doesn't matter -> i.e. -replace '\"', '\u0022'
+  # https://connect.microsoft.com/PowerShell/feedback/details/735978/convertto-json-in-psv3-beta-does-not-support-values-containing-double-quotes
+  if ($Text -match '"')
+  {
+    $old = $Text
+    $Text = $Text -replace '"', '""'
+    Write-Warning "Circumventing Powershell bug - replacing $Name string $old with $Text"
+  }
+
+  return $Text
+}
+
+function Merge-JsonNamedValue
+{
+  [CmdletBinding()]
+  param(
+    [Parameter(Mandatory = $true)]
+    [String]
+    $Name,
+
+    [Parameter(Mandatory = $true)]
+    [PSCustomObject]
+    $Destination,
+
+    [Parameter(Mandatory = $true)]
+    $Value
+  )
+
+  if (!$Destination.$Name)
+  {
+    $Destination |
+      Add-Member -Name $Name -Value $Value -MemberType NoteProperty
+  }
+  else
+  {
+    $Destination.$Name = $Value
+  }
+}
+
+function Merge-JsonArray
+{
+  [CmdletBinding()]
+  param(
+    [Parameter(Mandatory = $true)]
+    [String]
+    $Name,
+
+    [Parameter(Mandatory = $true)]
+    [PSCustomObject]
+    $Destination,
+
+    [Parameter(Mandatory = $true)]
+    [Object[]]
+    $Array
+  )
+
+  if (!$Destination.$Name)
+  {
+    $Destination |
+      Add-Member -Name $Name -Value $Array -MemberType NoteProperty
+  }
+  else
+  {
+    $Destination.$Name = ($Destination.$Name + $Array | Sort-Object -Unique)
+  }
+}
+
+function Merge-JsonSimpleMap
+{
+  [CmdletBinding()]
+  param(
+    [Parameter(Mandatory = $true)]
+    [String]
+    $Name,
+
+    [Parameter(Mandatory = $true)]
+    [PSCustomObject]
+    $Destination,
+
+    [Parameter(Mandatory = $true)]
+    [PSCustomObject]
+    $SimpleMap
+  )
+
+  if (!$Destination.$Name)
+  {
+    $Destination |
+      Add-Member -Name $Name -Value $SimpleMap -MemberType NoteProperty
+  }
+  else
+  {
+    $currentHash = $Destination.$Name
+    $SimpleMap.PSObject.Properties |
+      % {
+        $currentHash.($_.Name) = $_.Value
+      }
+  }
+}
+
+function Create-CustomObjectKey
+{
+ [CmdletBinding()]
+  param(
+    [Parameter(Mandatory = $true)]
+    [PSCustomObject]
+    $Object
+  )
+
+  $key = ''
+  $Object.PSObject.Properties |
+    % {
+      $key += "{$($_.Name):$($_.Value)}"
+    }
+
+  return $key
+}
+
+function Merge-JsonArrayOfSimpleMap
+{
+  [CmdletBinding()]
+  param(
+    [Parameter(Mandatory = $true)]
+    [String]
+    $Name,
+
+    [Parameter(Mandatory = $true)]
+    [PSCustomObject]
+    $Destination,
+
+    [Parameter(Mandatory = $true)]
+    [Object[]]
+    $Array
+  )
+
+  if (!$Destination.$Name)
+  {
+    $Destination |
+      Add-Member -Name $Name -Value $Array -MemberType NoteProperty
+  }
+  else
+  {
+    $merged = $Destination.$Name + $Array
+    $seen = @()
+    $Destination.$Name = $merged |
+      ? { $seen -inotcontains (Create-CustomObjectKey $_) } |
+      % {
+        $seen += (Create-CustomObjectKey $_)
+        $_
+      }
+  }
+}