Update Object in JSON file using Powershell

Question

I'm trying to update the list object in the following file using Powershell:

{
"$schema":  "https://schema.management.azure.com/schemas/2019-04-01/deploymentParameters.json#",
"contentVersion":  "1.0.0.0",
"parameters":  {
    "environment":  {
            "value":  ""
        },
    "keyVaultAccessPolicies":  {
        "value":  {
            "list": []
        }
    }
}

}

This is my Powershell that I have written so far:

$parametersTemplate = "C:\deploy.parameters.json"
$parametersJson = Get-Content $parametersTemplate -Raw | ConvertFrom-Json
$parametersJson.parameters.keyVaultAccessPolicies.value.list = $armAccessPolicies
$parametersJson | ConvertTo-Json | % { [System.Text.RegularExpressions.Regex]::Unescape($_) } | Set-Content $parametersTemplate

$armAccessPolices is a json string that looks like this:

[
{
    "tenantId":"**************",
    "objectId":"**************",
    "permissions":{"keys":"","secrets":"Get","certificates":"","storage":""}
},
{
    "tenantId":"**************",
    "objectId":"**************",
    "permissions":{"keys":"","secrets":"Get","certificates":"","storage":""}
}
]

When the JSON file is updated the result I am getting is this:

"keyVaultAccessPolicies":  {
      "value":  "@{list=[...]}"
  }

I'd like some advice so the file looks like this:

"keyVaultAccessPolicies":  {
      "value":  {
           "list": [...]
      }
  }

Sage Pourpre · Accepted Answer · 2021-01-16 19:49:09Z

2

You kind of answer your own question when you say that $armAccessPolices is a json string.

You are appending a string to $parametersJson.parameters.keyVaultAccessPolicies.value.list.

What you want is to append a list. To do so, you need to convert $armAccessPolicies to a PSObject first and then convert everything back to the final json, like this:

$parametersTemplate = "C:\deploy.parameters.json"
$parametersJson = Get-Content $parametersTemplate -Raw | ConvertFrom-Json
# See, we are not setting the json string but rather the resulting psobject.
$parametersJson.parameters.keyVaultAccessPolicies.value.list = ($armAccessPolicies | ConvertFrom-Json) 

$parametersJson | ConvertTo-Json -Depth 10 | % { [System.Text.RegularExpressions.Regex]::Unescape($_) } | Set-Content $parametersTemplate

The only meaningful change here was the .list assignement which now is set to the psobject representation of $armAccessPolicies instead of the raw string through ($armAccessPolicies | ConvertFrom-Json)

Note: You should also define the depth to something bigger than 4 (default) to avoid data loss after the 4th layer.

answered Jan 16, 2021 at 19:49

Sage Pourpre

10.4k3 gold badges30 silver badges43 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

Lymedo Over a year ago

Thanks for this. Works as expected now. Think I’d been staring at it for too long to see the obvious answer.

Lymedo Over a year ago

Also, thanks for the advice on the Depth. I was seeing some objects instead of values and increasing the depths has fixed it.

Lymedo Over a year ago

Is there a way that $armAccessPolicies can always be treated as an array when converted to json? "list" is an array but when $armAccessPolicies.PSobject.BaseObject.Count = 1, "list" is treated as an object so I get a bad json file.

Lymedo Over a year ago

Worked it out: $armAccessPolicies = [PSCustomObject]@{ list = $armAccessPolicies} and then $parametersJson.parameters.keyVaultAccessPolicies.value = $AccessPoliciesObject (update value instead of list)

Collectives™ on Stack Overflow

Update Object in JSON file using Powershell

1 Answer 1

4 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

4 Comments

Your Answer

Sign up or log in

Post as a guest

Related