PSResourceGet: Register-PSRepository raises errors about "invalid Web Uri", despite underlying httpclient recognizing the Uri and [Uri] parsing

I have a very simple problem I want to solve: Due to reasons beyond my control, the company I work for uses a “.local” domain name internally, for everything. My repository url is “http://packages.mycompany.local/nuget/Mycompany-Development/api/v2” - which according to Register-PSRepository is not a “Web Uri” (whatever the heck that means).

It appears this is a bogus error message, largely due to the sophisticated and overly complicated sanity checks Register-PSRepository tries to perform. I’ve extracted all the required sub-functions to replicate the behavior, modulo the final error trap that surfaces the wrong error.

function Get-LocationString
{
    [CmdletBinding(PositionalBinding=$false)]
    Param
    (
        [Parameter()]
        [Uri]
        $LocationUri
    )

    $LocationString = $null

    if($LocationUri)
    {
        if($LocationUri.Scheme -eq 'file')
        {
            $LocationString = $LocationUri.OriginalString
        }
        elseif($LocationUri.AbsoluteUri)
        {
            $LocationString = $LocationUri.AbsoluteUri
        }
        else
        {
            $LocationString = $LocationUri.ToString()
        }
    }

    return $LocationString
}

function Resolve-Location
{
    [CmdletBinding()]
    [OutputType([string])]
    Param
    (
        [Parameter(Mandatory=$true)]
        [string]
        $Location,

        [Parameter(Mandatory=$true)]
        [string]
        $LocationParameterName,

        [Parameter()]
        $Credential,

        [Parameter()]
        $Proxy,

        [Parameter()]
        $ProxyCredential,

        [Parameter()]
        [System.Management.Automation.PSCmdlet]
        $CallerPSCmdlet
    )

    # Ping and resolve the specified location
    if(-not (Test-WebUri -uri $Location))
    {
        if(Microsoft.PowerShell.Management\Test-Path -Path $Location)
        {
            return $Location
        }
        elseif($CallerPSCmdlet)
        {
            $message = $LocalizedData.PathNotFound -f ($Location)
            ThrowError -ExceptionName "System.ArgumentException" `
                       -ExceptionMessage $message `
                       -ErrorId "PathNotFound" `
                       -CallerPSCmdlet $CallerPSCmdlet `
                       -ErrorCategory InvalidArgument `
                       -ExceptionObject $Location
        }
    }
    else
    {
        $pingResult = Ping-Endpoint -Endpoint $Location -Credential $Credential -Proxy $Proxy -ProxyCredential $ProxyCredential
        $statusCode = $null
        $exception = $null
        $resolvedLocation = $null
        if($pingResult -and $pingResult.ContainsKey($Script:ResponseUri))
        {
            $resolvedLocation = $pingResult[$Script:ResponseUri]
        }

        if($pingResult -and $pingResult.ContainsKey($Script:StatusCode))
        {
            $statusCode = $pingResult[$Script:StatusCode]
        }

        Write-Debug -Message "Ping-Endpoint: location=$Location, statuscode=$statusCode, resolvedLocation=$resolvedLocation"

        if((($statusCode -eq 200) -or ($statusCode -eq 401)) -and $resolvedLocation)
        {
            return $resolvedLocation
        }
        elseif($CallerPSCmdlet)
        {
            $message = $LocalizedData.InvalidWebUri -f ($Location, $LocationParameterName)
            ThrowError -ExceptionName "System.ArgumentException" `
                       -ExceptionMessage $message `
                       -ErrorId "InvalidWebUri" `
                       -CallerPSCmdlet $CallerPSCmdlet `
                       -ErrorCategory InvalidArgument `
                       -ExceptionObject $Location
        }
    }
}

function Test-WebUri
{
    [CmdletBinding()]
    [OutputType([bool])]
    Param
    (
        [Parameter(Mandatory=$true)]
        [ValidateNotNullOrEmpty()]
        [Uri]
        $uri
    )

    return ($uri.AbsoluteURI -ne $null) -and ($uri.Scheme -match '[http|https]')
}

function Ping-Endpoint
{
    [CmdletBinding()]
    param
    (
        [Parameter()]
        [ValidateNotNullOrEmpty()]
        [string]
        $Endpoint,

        [Parameter()]
        $Credential,

        [Parameter()]
        $Proxy,

        [Parameter()]
        $ProxyCredential,

        [Parameter()]
        [switch]
        $AllowAutoRedirect = $true
    )

    $results = @{}

    $WebProxy = $null
    if($Proxy -and ('Microsoft.PowerShell.Commands.PowerShellGet.InternalWebProxy' -as [Type]))
    {
        $ProxyNetworkCredential = $null
        if($ProxyCredential)
        {
            $ProxyNetworkCredential = $ProxyCredential.GetNetworkCredential()
        }

        $WebProxy = New-Object Microsoft.PowerShell.Commands.PowerShellGet.InternalWebProxy -ArgumentList $Proxy,$ProxyNetworkCredential
    }

    if(HttpClientApisAvailable)
    {
        $response = $null
        try
        {
            $handler = New-Object System.Net.Http.HttpClientHandler

            if($Credential)
            {
                $handler.Credentials = $Credential.GetNetworkCredential()
            }
            else
            {
                $handler.UseDefaultCredentials = $true
            }

            if($WebProxy)
            {
                $handler.Proxy = $WebProxy
            }

            $httpClient = New-Object System.Net.Http.HttpClient -ArgumentList $handler
            $response = $httpclient.GetAsync($endpoint)
        }
        catch
        {
        }

        if ($response -ne $null -and $response.result -ne $null)
        {
            Write-Host $response.Result
            $results.Add($Script:ResponseUri,$response.Result.RequestMessage.RequestUri.AbsoluteUri.ToString())
            $results.Add($Script:StatusCode,$response.result.StatusCode.value__)
        }
    }
    else
    {
        $iss = [System.Management.Automation.Runspaces.InitialSessionState]::Create()
        $iss.types.clear()
        $iss.formats.clear()
        $iss.LanguageMode = "FullLanguage"

        $WebRequestcmd =  @'
            param($Credential, $WebProxy)
            try
            {{
                $request = [System.Net.WebRequest]::Create("{0}")
                $request.Method = 'GET'
                $request.Timeout = 30000
                if($Credential)
                {{
                    $request.Credentials = $Credential.GetNetworkCredential()
                }}
                else
                {{
                    $request.Credentials = [System.Net.CredentialCache]::DefaultNetworkCredentials
                }}
                $request.AllowAutoRedirect = ${1}
                if($WebProxy)
                {{
                    $request.Proxy = $WebProxy
                }}
                $response = [System.Net.HttpWebResponse]$request.GetResponse()
                if($response.StatusCode.value__ -eq 302)
                {{
                    $response.Headers["Location"].ToString()
                }}
                else
                {{
                    $response
                }}
                $response.Close()
            }}
            catch [System.Net.WebException]
            {{
                "Error:System.Net.WebException"
            }}
'@ -f $EndPoint, $AllowAutoRedirect

        $ps = [powershell]::Create($iss).AddScript($WebRequestcmd)

        if($WebProxy)
        {
            $null = $ps.AddParameter('WebProxy', $WebProxy)
        }

        if($Credential)
        {
            $null = $ps.AddParameter('Credential', $Credential)
        }

        $response = $ps.Invoke()
        $ps.dispose()
        if ($response -ne "Error:System.Net.WebException")
        {
            if($AllowAutoRedirect)
            {
                $results.Add($Script:ResponseUri,$response.ResponseUri.ToString())
                $results.Add($Script:StatusCode,$response.StatusCode.value__)
            }
            else
            {
                $results.Add($Script:ResponseUri,[String]$response)
            }
        }
    }
    return $results
}

function HttpClientApisAvailable
{
    $HttpClientApisAvailable = $false
    try
    {
        [System.Net.Http.HttpClient]
        $HttpClientApisAvailable = $true
    }
    catch
    {
    }
    return $HttpClientApisAvailable
}

$SourceLocation = [Uri] "http://packages.mycompany.local/nuget/Mycompany-Development/api/v2" 

# Ping and resolve the specified location
            $SourceLocation = Resolve-Location -Location (Get-LocationString -LocationUri $SourceLocation) `
                                               -LocationParameterName 'SourceLocation' `
                                               -Credential $Credential `
                                               -Proxy $Proxy `
                                               -ProxyCredential $ProxyCredential `
                                               -CallerPSCmdlet $PSCmdlet

I’m not 100% sure, but I think the issue is that Resolve-Location treats any failures as “Web Uri” failures, even though the error appears to be due to $Script:$ResponseUri not existing/being a null key. (I’m not a PowerShell expert and while I generally understand the concept of scope-modifiers, I generally program in C# where you can’t dynamically change scopes. To a C# programmer, this looks like bad code or non-sensical code.)

This appears to be an issue since PowerShellGet was called OneGet: https://github.com/OneGet/TestBuild/issues/2

In that issue, it appears that Ping-Endpoint was to blame. Oddly, this was 3 years ago and still not fixed as OneGet got renamed PowerShellGet.