// Fetch content and determine boundary
$raw_data = file_get_contents('php://input');
$boundary = substr($raw_data, 0, strpos($raw_data, "\r\n"));

// Fetch each part
$parts = array_slice(explode($boundary, $raw_data), 1);
$data = array();

foreach ($parts as $part) {
    // If this is the last part, break
    if ($part == "--\r\n") break; 

    // Separate content from headers
    $part = ltrim($part, "\r\n");
    list($raw_headers, $body) = explode("\r\n\r\n", $part, 2);

    // Parse the headers list
    $raw_headers = explode("\r\n", $raw_headers);
    $headers = array();
    foreach ($raw_headers as $header) {
        list($name, $value) = explode(':', $header);
        $headers[strtolower($name)] = ltrim($value, ' '); 
    } 

    // Parse the Content-Disposition to get the field name, etc.
    if (isset($headers['content-disposition'])) {
        $filename = null;
        preg_match(
            '/^(.+); *name="([^"]+)"(; *filename="([^"]+)")?/', 
            $headers['content-disposition'], 
            $matches
        );
        list(, $type, $name) = $matches;
        isset($matches[4]) and $filename = $matches[4]; 

        // handle your fields here
        switch ($name) {
            // this is a file upload
            case 'userfile':
                 file_put_contents($filename, $body);
                 break;

            // default for all other files is to populate $data
            default: 
                 $data[$name] = substr($body, 0, strlen($body) - 2);
                 break;
        } 
    }

}