Get-RemoteCertificate.ps1

Get-RemoteCertificate.ps1

function Get-RemoteCertificate { 
    <#
    .SYNOPSIS
        Retrieves the SSL certificate from a remote server.
    .DESCRIPTION
        The Get-RemoteCertificate function connects to a specified remote server using its URI and retrieves the SSL certificate. It uses a TcpClient to establish the connection and an SslStream to perform the SSL handshake. The function returns the remote server's SSL certificate as an X509Certificate object.
    .PARAMETER Uri
        The URI of the remote server from which to retrieve the SSL certificate. This parameter is mandatory and accepts pipeline input.
    .PARAMETER TimeoutMilliseconds
        The timeout period in milliseconds for the connection attempt. The default value is 500 milliseconds.
    .EXAMPLE
        PS> Get-RemoteCertificate -Uri "https://example.com"
        This command retrieves the SSL certificate from the server at https://example.com.
    .EXAMPLE
        PS> "https://example.com" | Get-RemoteCertificate
        This command retrieves the SSL certificate from the server at https://example.com using pipeline input.
    #>
    
    [CmdletBinding()]
    [OutputType([System.Security.Cryptography.X509Certificates.X509Certificate])]
    param (
        [Parameter(
            Mandatory,
            ValueFromPipeline
        )]
        [ValidateNotNull()]
        [Uri]
        $Uri,

        [int]
        $TimeoutMilliseconds = 500 # Default timeout is 500 milliseconds
    )
    process {
        try {
            $TcpClient = [System.Net.Sockets.TcpClient]::new()
            $connectTask = $TcpClient.ConnectAsync($Uri.Host, $Uri.Port)

            if ($connectTask.Wait($TimeoutMilliseconds)) {
                $SslStream = [System.Net.Security.SslStream]::new($TcpClient.GetStream(), $false, { $true })
                $SslStream.AuthenticateAsClient($Uri.Host)
                $SslStream.RemoteCertificate
            }
            else {
                Throw "Conenction Timeout"
            }
        } 
        catch {
            Throw "$($_.Exception.Message)"
        }
        finally {
            if ($TcpClient.Connected) {
                $SslStream.Dispose()
            }
            $TcpClient.Close()
        }
    }
 }