PowerShell JSON set value - json

Question

Folks,
I do run in PowerShell some ReST api call and do get back a
$response
page content
---- -------
#{size=20; number=0; totalPages=1; totalElements=1} {#{id=ZGR2ZS0yLnZsYWIubG9j…
When I convert to JSON
PS C:\Users\Administrator\Documents> $response | ConvertTo-Json
{
"page": {
"size": 20,
"number": 0,
"totalPages": 1,
"totalElements": 1
},
"content": [
{
"id": "ZGR2ZS0yLnZsYWIubG9jYWw6MzAwOTpob3N0",
"host": "ddve-2.vlab.local",
"port": "3009",
"notValidBefore": "Fri Mar 29 21:32:19 PDT 2019",
"notValidAfter": "Sat Mar 29 04:32:19 PDT 2025",
"fingerprint": "E1BB40B0284595297071177FE02BC9C76E85CD66",
"subjectName": "CN=ddve-2.vlab.local, O=Valued DataDomain customer, OU=Hos
t Certificate, ST=CA, C=US",
"issuerName": "CN=ddve-2.vlab.local, OU=Root CA, O=Valued Datadomain Custo
mer, L=Santa Clara, ST=CA, C=US",
"state": "ACCEPTED",
"type": "HOST"
}
]
}
an idividual value can be seen
PS C:\Users\Administrator\Documents> $response.content.state
ACCEPTED
But setting a new value fails
PS C:\Users\Administrator\Documents> $response.content.state = 123
InvalidOperation: The property 'state' cannot be found on this object. Verify th
at the property exists and can be set.

Answer 1

Because your content property is a (single-element) array (as evidenced by its value being enclosed in [ ... ] in the JSON representation), you must use an index to specify which element's .state property to set:
$response.content[0].state = 123
Note that an index is not required for getting the value (that is, $response.content.state works and returns "ACCEPTED", as you state), because PowerShell then applies member-access enumeration, which means that it enumerates the state property values of all elements of the array (which with a single-element array returns just the single element's value, and with a multiple-element array returns an array of values).
On setting a property value, member-access enumeration is by design not supported, although the error message could certainly be more helpful - see this answer.

Answer 2

Your object is a PSCustomObject and the value you're trying to change is a NoteProperty on that object, you can use Add-Member with the -Force switch to overwrite it.
$Response = #"
{
"page": {
"size": 20,
"number": 0,
"totalPages": 1,
"totalElements": 1
},
"content": [
{
"id": "ZGR2ZS0yLnZsYWIubG9jYWw6MzAwOTpob3N0",
"host": "ddve-2.vlab.local",
"port": "3009",
"notValidBefore": "Fri Mar 29 21:32:19 PDT 2019",
"notValidAfter": "Sat Mar 29 04:32:19 PDT 2025",
"fingerprint": "E1BB40B0284595297071177FE02BC9C76E85CD66",
"subjectName": "CN=ddve-2.vlab.local, O=Valued DataDomain customer, OU=Hos
t Certificate, ST=CA, C=US",
"issuerName": "CN=ddve-2.vlab.local, OU=Root CA, O=Valued Datadomain Custo
mer, L=Santa Clara, ST=CA, C=US",
"state": "ACCEPTED",
"type": "HOST"
}
]
}
"# | ConvertFrom-Json
$Response.Content.State
$Response.Content | Add-Member -MemberType NoteProperty -Name State -Value 123 -Force
$Response.Content.State
Output
ACCEPTED
123