Suggestion - Add proxy support

从 Prereq 脚本开始，检查其中对 Invoke-WebRequest、Install-PackageProvider 和 Find-DscResource/Save-Module 的调用。确定应如何提供代理和凭据设置，然后验证通过代理安装前置模块时无需在脚本外进行手动设置即可正常工作。

I was behind a proxy here and I had to change the script to add "-Proxy $Proxy -ProxyCredential $MyCreds" at the end of each "Invoke-WebRequest" cmdlet.

Same thing for "Install-PackageProvider -Name NuGet"

But then, i got error with "Find-DscResource -moduleName $modulename -RequiredVersion $moduleversion | Save-Module -Path "$PSScriptRoot\Temp\DSC"

I've search a long time and try these configuration without success :

Setting TLS 1.2 : [Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
Bypassing the certificate validation : [Net.ServicePointManager]::ServerCertificateValidationCallback = {$true};
Bypassing the certificate validation by code instead of block :
#C# class to create callback
$code = @"
public class SSLHandler
{
public static System.Net.Security.RemoteCertificateValidationCallback GetSSLHandler()
{

    return new System.Net.Security.RemoteCertificateValidationCallback((sender, certificate, chain, policyErrors) => { return true; });
}

}
"@
#compile the class
Add-Type -TypeDefinition $code

#disable checks using new class
[System.Net.ServicePointManager]::ServerCertificateValidationCallback = [SSLHandler]::GetSSLHandler()

No success!! but then i've found way to configure default proxy but i wasnt able to add it to the script, and I had to install the module outside of the "Prereq" script. here what I use for this to work :

$proxy = 'YER PROXY HERE' # update this
[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
[system.net.webrequest]::defaultwebproxy = new-object system.net.webproxy($proxy)
[system.net.webrequest]::defaultwebproxy.credentials = [System.Net.CredentialCache]::DefaultNetworkCredentials
[system.net.webrequest]::defaultwebproxy.BypassProxyOnLocal = $true

Install-PackageProvider -Name nuget -Scope AllUsers -Confirm:$false -Force -MinimumVersion 2.8.5.201
Register-PSRepository -Default -verbose

Install-Module -Name xActiveDirectory -Scope AllUsers -Confirm:$false -Force
Install-Module -Name xDHCpServer -Scope AllUsers -Confirm:$false -Force
Install-Module -Name xDNSServer -Scope AllUsers -Confirm:$false -Force
Install-Module -Name NetworkingDSC -Scope AllUsers -Confirm:$false -Force
Install-Module -Name xPSDesiredStateConfiguration -Scope AllUsers -Confirm:$false -Force

Probably there more "code head" people who can help with this since it's ugly but working :)

Thanks again for the great script!