How to detect uploads exceeding POST maximum size in Slim framework

detect-upload-errors.php

<?php
$env = $app->environment();

if ($env['REQUEST_METHOD'] == 'POST') {
    $contentLength = intval($env['CONTENT_LENGTH']);
    $postMaxSize = ini_get('post_max_size');
    if (preg_match('/^(\\d+)([PTGMK])$/iu', $postMaxSize, $matches)) {
        $postMaxSize = intval($matches[1]);

        switch (strtoupper($matches[2])) {
            case 'P': $postMaxSize *= 1024;
            case 'T': $postMaxSize *= 1024;
            case 'G': $postMaxSize *= 1024;
            case 'M': $postMaxSize *= 1024;
            case 'K': $postMaxSize *= 1024;
        }
    } else {
        $postMaxSize = intval($postMaxSize);
    }

    if ($contentLength > $postMaxSize) {
        $app->error(
            new RuntimeException(
                "Content-length (=$contentLength) > Post maximum size (=$postMaxSize)"
            )
        );
    }
}