Replace parameters in JSON with given Values from .csv - json

Question

I have a JSON-File where I want to replace several values with a placeholder.
So i made a .csv with the parameters to replace. line[0] (if existing) is the path in the file, line[1] the element, line[2] the placeholder.
journeys.legs.origin.properties.downloads;url;placeholder;
;url;placeholder;
download;url;placeholder;
;psFileName;placeholder;
;serverTime;placeholder;
;calcTime;placeholder;
now I defined the following functions, to get the file, read the csv and replace the stuff.
$storage = "D:\Service\test.json"
$parameters2replace = "D:\Service\parameters2replace.csv"
function Get-JSONProperty([object] $InputObject, [string] $Property) {
$path = $Property -split '\.'
$obj = $InputObject
$path | %{ $obj = $obj.$_ }
$obj
}
function setParameter(){
foreach ($parameter in Get-Content $parameters2replace){
$line=$parameter.split(";")
$path = $line[0]
$elementName = $line[1]
$newValue = $line[2]
replaceElement $path $elementName $newValue
}
}
function replaceElement($path, $elementName, $newValue){
ForEach($JSONPath in Get-JSONProperty $JSON $path){
if (!$line[0]){
if($JSON.$elementName){
$JSON.$elementName = $newValue
}
}
else{
if($JSON.$path.$elementName){
echo $JSON.$path.$elementName
$JSON.$path.$elementName = $newValue
}
}
}
$JSON | ConvertTo-Json -depth 32| set-content $storage
}
$JSON = Get-Content $storage -raw | ConvertFrom-Json
setParameter
My problem now is, that the following if-argument won't work with the $path variable. If i put it in hardcoded it works just fine.
if($JSON.$path.$elementName)
I hope i could make everything clear, this was my first post.

Answer 1

$JSON.$path makes PowerShell look for a property with the literal name 'journeys.legs.origin.properties.downloads'. You need to split the string into it's individual parts and iterate (or recurse) through the path:
function Get-JSONPropertyValue {
param(
$JSON,
[string]$Path,
[string]$Name
)
$object = $JSON
foreach($propName in $Path.Split('.')){
$object = $object.$propName
}
return $object.$Name
}
function Set-JSONPropertyValue
{
param(
$JSON,
[string]$Path,
[string]$Name,
$Value
)
$object = $JSON
foreach($propName in $Path.Split('.')){
$object = $object.$propName
}
$object.$Name = $Value
}
Now you can do:
if($value = Get-JSONPropertyValue $JSON -Path $path -Name $elementName){
echo "Old value: $value"
Set-JSONPropertyValue $JSON -Path $path -Name $elementName -Value $newValue
}