Private/Test-FPControlSource.ps1

function Test-FPControlSource {
    <#
    .SYNOPSIS
        Validate File or URI is accessible
    .DESCRIPTION
        Verifies Control XML file is accessible
    .PARAMETER Path
        Full Path or URI to file
    .INPUTS
        Path to file
    .OUTPUTS
        $True or $null
    #>

    param (
        [parameter(Mandatory = $True)][ValidateNotNullOrEmpty()][string] $Path
    )
    if ($Path.StartsWith('http')) {
        Write-FPLog "verifying URI resource: $Path"
        try {
            $test = Invoke-WebRequest -UseBasicParsing -Uri $Path -Method Get -ErrorAction SilentlyContinue
            if ($test) {
                Write-Output ($test.StatusCode -eq 200)
            }
        } catch {}
    } else {
        Write-FPLog "verifying file system resource: $Path"
        Write-Output (Test-Path $Path)
    }
}