Replace a value in a JSON file using Powershell - json

Question

How can I replace a value in a JSON file with another value taken from a config file (JSON)?
This is the code for the JSON files:
Config.json
{
"ABlob_AAD_Snapshot": [
{
"name": "properties.availability.frequency",
"value": "$Frequency$"
}]
}
ABlob_AAD_Snapshot.json
{
"name": "AzureBlobStore",
"properties": {
"type": "AzureStorage",
"availability": {
"frequency": "Value from Config.json file"
}
}
}
What I'm trying to do is the following:
Go through the Config.json file and store the values for "name" and "value" segments in variables. The "name" segment value is a path in ABlob_AAD_Snapshot.json file.
Follow the path in the ABlob_AAD_Snapshot.json file and replace the segment "frequency" with the value of segment "value" ($frequency$)
After this process, the ABlob_AAD_Snapshot.json should look like this:
{
"name": "AzureBlobStore",
"properties": {
"type": "AzureStorage",
"availability": {
"frequency": "$frequency$"
}
}
}
The problem here is that my original config.json file has more than one array (which represents file names) so I will parse more than one file and the value for "name" segment will not always be the same I mean, in this case, the value (or path) is properties.availability.frequency but it could be properties.activities.scheduler.interval or properties.activities.typeProperties.extendedProperties.WebAppClientID.
So as you can see the name and the quantity of "nodes" could change.
This is my PowerShell script:
$ScriptPath = split-path -parent $MyInvocation.MyCommand.Definition
#path to config file
$ConfigFile = "$ScriptPath\ParameterConfigOriginal.json"
#Convert the json file to PSObject
$json = Get-Content $ConfigFile | Out-String | ConvertFrom-Json
#Get all the arrays (files) in Conifg.json
$files = $json | Get-Member -MemberType Properties | Select-Object -ExpandProperty Name
#Go through all the arrays (files)
Foreach($file in $files)
{
if( $file -eq '$schema') {continue}
#store the path of the file to be modified
$FileName = $file + ".json"
$FilePath = "$ScriptPath\LinkedServices\" + $FileName"
#Go through all the elements of the arrray
Foreach($item in $json.$file)
{
#Store the path
$name = $item.name
#Store the value
$value = $item.value
#Convert the file to be modified to PSObject
$file = Get-Content $FilePath | Out-String | ConvertFrom-Json
#======STUCK IN HERE=============
# How can dynamically navigate through the file nodes like this?
$file.properties.availability.frequency
#and set the corresponding value
$file.properties.availability.frequency = $value
}
}
I'm new in the PowerShell world and I don't know if there is a cmdlet that helps me to do what I need.
Any suggestion will be appreciated.
EDIT
Simple Path
$snapshot.properties.availability.frequency
Path with arrays
$snapshot.properties.activities[0].scheduler.frequency
this is an example of the JSON file with arrays
Destination file
and this is the result
Destination file updated
Any idea on what could be happening?

Answer 1

Invoke-Expression will help you.
#Go through all the arrays (files)
Foreach($file in $files)
{
$snapshot = (Get-Content ("./" + $file + ".json") | ConvertFrom-Json)
# get config corresponds to the $file
$config = Invoke-Expression ('$json.' + $file)
# set value according to the config
Invoke-Expression ('$snapshot.' + $config.name + "='" + $config.value + "'")
# $snapshot.properties.availability.frequency
# -> $Frequency$
}
Edit
You have to use ConvertTo-Json -Depth 100 to write the result to JSON file properly (specify the appropriate depth according to your JSON files.).
Without -Depth option, you will get the result like "#{type=Copy, typeProperties=;, ...}".