Can't find expected json body in System.Net.WebException - rest

Question

I'm working with an API via PowerShell that returns human-readable errors as a json object in the response body when an error occurs. However, when I attempt to find that json body in an exception, I can see the error, the underlying System.Net.WebException and the further underlying System.Net.HttpWebResponse, but nowhere can I find the actual body they're referring to. Is this something that is accessible?
For example, here is a valid API call that would work:
Invoke-RestMethod -Method Get -Headers #{Authorization="Token token=$YourTokenHere";"Content-type"="application/json"} -Uri "https://mydomain.pagerduty.com/api/v1/users/ABCDEF" -Body #{offset=0;limit=100}
If you then change the user ID at the end of the URI, it fails and you get this error:
Invoke-RestMethod : The remote server returned an error: (400) Bad Request.
At line:1 char:1
+ Invoke-RestMethod -Method Get -Headers #{Authorization="Token token=b ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (System.Net.HttpWebRequest:HttpWebRequest) [Invoke-RestMethod], WebException
+ FullyQualifiedErrorId : WebCmdletWebResponseException,Microsoft.PowerShell.Commands.InvokeRestMethodCommand
I can dive down in to the error to see the underlying error and the response if I do the following and convert to json for easy viewing of subproperties:
$Error[0].Exception.Response | ConvertTo-Json
But no matter how I comb through these errors, I can't seem to find the json body. Where might it be, or how can I capture it? I seem to have the same result if I do a try/catch.

Answer 1

You could read the responsestream so you can get the body of the response. Ex:
try {
Invoke-RestMethod -Method Get -Headers #{Authorization="Token token=$YourTokenHere";"Content-type"="application/json"} -Uri "https://mydomain.pagerduty.com/api/v1/users/ABCDEF" -Body #{offset=0;limit=100}
} catch {
$stream = New-Object System.IO.StreamReader $_.Exception.Response.GetResponseStream()
$json = $stream.ReadToEnd()
$stream.Dispose()
$json
}
Output:
{"error":{"message":"Account Not Found","code":2007}}