Format for json via powershell - powershell

Question

I'm trying to use powershell to send json to DevOps API. I can't seem to figure out how to properly format this so powershell will take it. I keep getting this error. Any advice? I'm able to use the same json in Postman without any issues. Thanks
$URI= "https://vsaex.dev.azure.com/$ClientOrg/_apis/userentitlements?api-version=5.1-preview.2" $AzureDevOpsAuthenicationHeader = #{Authorization = 'Basic ' + [Convert]::ToBase64String([Text.Encoding]::ASCII.GetBytes(":$($PAT)")) }
Invoke-RestMethod -uri $URI -Method POST -Headers $AzureDevOpsAuthenicationHeader -Body $a -ContentType "application/json"
$a= ConvertFrom-JSON #'
{
"accessLevel": {
"licensingSource": "msdn",
"accountLicenseType": "enterprise",
"msdnLicenseType": "enterprise"
},
"extensions": [
{
"id": "ms.feed"
}
],
"user": {
"principalName": "email#mail.com",
"subjectKind": "user"
},
"projectEntitlements": [
{
"group": {
"groupType": "projectAdministrator"
},
"projectRef": {
"id": "0685a10e"
}
}
]
}
'#
Invoke-RestMethod : {"$id":"1","innerException":null,"message":"Value cannot be null.\r\nParameter name: userEntitlement","typeName":"System.ArgumentNullException,
mscorlib","typeKey":"ArgumentNullException","errorCode":0,"eventId":0}
At line:4 char:1
+ Invoke-RestMethod -uri $URI -Method POST -Headers $AzureDevOpsAutheni ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (System.Net.HttpWebRequest:HttpWebRequest) [Invoke-RestMethod], WebException
+ FullyQualifiedErrorId : WebCmdletWebResponseException,Microsoft.PowerShell.Commands.InvokeRestMethodCommand

Answer 1

Your body should be the JSON string itself and not an object built from the JSON.
$a= #'
{
"accessLevel": {
"licensingSource": "msdn",
"accountLicenseType": "enterprise",
"msdnLicenseType": "enterprise"
},
"extensions": [
{
"id": "ms.feed"
}
],
"user": {
"principalName": "email#mail.com",
"subjectKind": "user"
},
"projectEntitlements": [
{
"group": {
"groupType": "projectAdministrator"
},
"projectRef": {
"id": "0685a10e"
}
}
]
}
'#
Invoke-RestMethod -uri $URI -Method POST -Headers $AzureDevOpsAuthenicationHeader -Body $a -ContentType "application/json"