Powershell to Upload File to PHP Page

In the previous post, a PHP page was created to upload a file.  Below is powershell that can be used to upload a selected file from a windows computer to the PHP page.

add-type @"
using System.Net;
using System.Security.Cryptography.X509Certificates;
public class TrustAllCertsPolicy : ICertificatePolicy {
    public bool CheckValidationResult(
        ServicePoint srvPoint, X509Certificate certificate,
        WebRequest request, int certificateProblem) {
        return true;
    }
}
"@
[System.Net.ServicePointManager]::CertificatePolicy = New-Object TrustAllCertsPolicy
[System.Net.ServicePointManager]::SecurityProtocol = [System.Net.SecurityProtocolType]'Tls12'

# Name of the file to upload to server
$FileName = 'test4.txt';
# Location of file to upload
$FilePath = 'C:\users\thepcn3rd\test1.txt';
# URL of webserver (with SSL cert)
$URL = 'https://172.16.53.133/upload.php';

$fileBytes = [System.IO.File]::ReadAllBytes($FilePath);
$fileEnc = [System.Text.Encoding]::GetEncoding('ISO-8859-1').GetString($fileBytes);
$boundary = [System.Guid]::NewGuid().ToString(); 
$LF = "`r`n";

# Most difficult part is below...
$bodyLines = ( 
    "--$boundary",
    "Content-Disposition: form-data; name=`"f`"; filename=`"$FileName`"",
    "Content-Type: application/octet-stream$LF",
    $fileEnc,
    "--$boundary",
    "Content-Disposition: form-data; name=`"submit`"$LF",
    "Upload",
    "--$boundary--$LF" 
) -join $LF

Invoke-RestMethod -Uri $URL -Method Post -ContentType "multipart/form-data; boundary=`"$boundary`"" -Body $bodyLines