Invoke-Restmethod breaks script in PS 4.0

Question

I had a Powershell script that used Invoke-RestMethod that was working in powershell 3.0. However, I upgraded to powershell 4.0 to fix a bug in powershell 3. When I did so, my script seems to have stopped working.

$username = "Administrator" $password = "PASSWORD" $uri = "https://10.0.0.18/vmrest/users" $dictionary = New-Object "System.Collections.Generic.Dictionary[[String],[String]]" $base64AuthInfo = [Convert]::ToBase64String([Text.Encoding]::ASCII.GetBytes(("{0}:{1}" -f$username,$password))) $dictionary.Add("Authorization",$base64AuthInfo) Invoke-RestMethod -Uri $uri -Method GET -Headers $dictionary -Verbose

When I turn on the verbose switch, it gives me this response

VERBOSE: GET https://192.168.1.18/vmrest/users with 0-byte payload VERBOSE: received -1-byte response of content type

I also tried specifying the requested content type, but no dice $dictionary.Add("Accept","application/json") $dictionary.Add("Connection", "keep_alive")

Answer 1

One thing that sticks out at me is that since you're using HTTPS, I'm sure you must be getting certificate errors since your URL is an IP address.

You need to tell Powershell (the .NET framework, really,) to ignore certificate errors. Or else it will crap out on things such as Invoke-WebRequest.

Try this:

[Net.ServicePointManager]::ServerCertificateValidationCallback = {$true} 

It's a custom certificate validation callback that always returns true thereby effectively ignoring certificate problems.

Answer 2

Probably not an answer to your problem, but another point is that you don't have to construct basic authentication headers yourself:

$secPw = ConvertTo-SecureString $password -AsPlainText -Force $cred = New-Object PSCredential -ArgumentList $username,$secPw Invoke-RestMethod -Uri $uri -Method Get -Credential $cred 

It's especially useful if you're interactively prompting for credentials because you can just use Get-Credential and be done with it.