PowerShell 2.0 ConvertFrom-Json and ConvertTo-Json implementation

Question

I would like to monkeypatch a PowerShell 2.0 environment where the upgrade to 3.0 is not possible at this time.

I am looking for a PowerShell 2.0 script implementation of the ConvertFrom-Json cmdlet and ConvertTo-Json cmdlet that are in PowerShell 3.0.

I am most interested in the ConvertFrom-Json, but ConvertTo-Json would also be nice.

Answer 1

function ConvertTo-Json20([object] $item){
    add-type -assembly system.web.extensions
    $ps_js=new-object system.web.script.serialization.javascriptSerializer
    return $ps_js.Serialize($item)
}

function ConvertFrom-Json20([object] $item){ 
    add-type -assembly system.web.extensions
    $ps_js=new-object system.web.script.serialization.javascriptSerializer

    #The comma operator is the array construction operator in PowerShell
    return ,$ps_js.DeserializeObject($item)
}

If you're getting the error:

Add-Type : Could not load file or assembly 'System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35 or one of its dependencies. The system cannot find the file specified. "

... these registry commands can be run (more details):

   reg add hklm\software\microsoft\.netframework /v OnlyUseLatestCLR /t REG_DWORD /d 1 /f
   reg add hklm\software\wow6432node\microsoft\.netframework /v OnlyUseLatestCLR /t REG_DWORD /d 1 /f

Answer 2

Code with javascriptSerializer return objects with Dictionary inside. Modern convertfrom-JSON (4.0+) return objects only. This code transform deserialize object to modern output :)

function Iterate-Tree($jsonTree) {
    $result = @()
    foreach ($node in $jsonTree) {
        $nodeObj = New-Object psobject
        foreach ($property in $node.Keys) {
            if ($node[$property] -is [System.Collections.Generic.Dictionary[String, Object]] -or $node[$property] -is [Object[]]) {
                $inner = @()
                $inner += Iterate-Tree $node[$property]
                $nodeObj  | Add-Member -MemberType NoteProperty -Name $property -Value $inner
            } else {
                $nodeObj  | Add-Member -MemberType NoteProperty -Name $property -Value $node[$property]
                #$nodeHash.Add($property, $node[$property])
            }
        }
        $result += $nodeObj
    }
    return $result
}

function ConvertFrom-Json20{ 
    [cmdletbinding()]
    Param (
        [parameter(ValueFromPipeline=$true)][object] $PS_Object
    )

    add-type -assembly system.web.extensions
    $PS_JavascriptSerializer=new-object system.web.script.serialization.javascriptSerializer
    $PS_DeserializeObject = ,$PS_JavascriptSerializer.DeserializeObject($PS_Object) 

    #Convert Dictionary to Objects
    $PS_DeserializeObject = Iterate-Tree $PS_DeserializeObject

    return $PS_DeserializeObject
}