StreamNotifyPrinter - Print out PHP Stream Notifications to target channel (default: STDERR).

StreamNotifyPrinter.php

<?php
/**
 * StreamNotifyPrinter
 *
 * @author  hakre <http://hakre.wordpress.com>
 * @version 0.0.2
 * @example http://stackoverflow.com/a/24711469/367456
 * @link    https://gist.github.com/hakre/8ba2c0d49b7baf062acd
 */

/**
 * Class StreamNotifyPrinter
 *
 * @author hakre <http://hakre.wordpress.com>
 * @since  0.0.1
 */
class StreamNotifyPrinter
{
    private $constants = [
        'STREAM_NOTIFY_RESOLVE',
        'STREAM_NOTIFY_AUTH_REQUIRED',
        'STREAM_NOTIFY_COMPLETED',
        'STREAM_NOTIFY_FAILURE',
        'STREAM_NOTIFY_AUTH_RESULT',
        'STREAM_NOTIFY_REDIRECTED',
        'STREAM_NOTIFY_CONNECT',
        'STREAM_NOTIFY_FILE_SIZE_IS',
        'STREAM_NOTIFY_MIME_TYPE_IS',
        'STREAM_NOTIFY_PROGRESS',
    ];

    private $startTime;

    /**
     * @var resource stream handle of output channel
     */
    private $channel;

    /**
     * @param resource $channel (optional) file-handle for output, default is STDERR
     */
    public function __construct($channel = NULL) {
        if ($channel === NULL) {
            $channel = STDERR;
        }
        $this->channel = $channel;
    }

    /**
     * register notifies on context
     *
     * @param resource $context (optional) to register on, creates a new one if not set
     *
     * @return resource
     */
    public function registerOnContext($context = NULL) {
        if ($context === NULL) {
            $context = stream_context_create();
        }

        if (!is_resource($context)) {
            throw new InvalidArgumentException('Context must be a resource');
        }

        $result = stream_context_set_params($context, ["notification" => [$this, 'callback']]);
        if (!$result) {
            throw new UnexpectedValueException('Unable to set context notification parameter');
        }
        return $context;
    }

    private function message($message) {
        $now = microtime(true);
        $this->startTime || $this->startTime = $now;

        $timeStamp  = $this->getTimeStamp($now);
        $timePassed = sprintf("[%.5f]", $now - $this->startTime);

        fputs($this->channel, "$timeStamp $timePassed $message\n");
    }

    private function dump() {
        ob_start();
        call_user_func_array('var_dump', func_get_args());
        $buffer = ob_get_clean();
        $this->message("Dump: " . $buffer);
    }

    private function getTimeStamp($from = NULL) {
        $from || $from = microtime(true);
        return date_create_from_format(
            'U.u', sprintf('%.f', $from)
        )->format('Y-m-d\TH:i:s.uO');
    }

    /**
     * @param $notification_code
     * @param $severity
     * @param $message
     * @param $message_code
     * @param $bytes_transferred
     * @param $bytes_max
     *
     * @see http://php.net/manual/en/function.stream-notification-callback.php
     */
    public function callback($notification_code, $severity, $message, $message_code, $bytes_transferred, $bytes_max) {
        switch ($notification_code) {
            case STREAM_NOTIFY_RESOLVE:
            case STREAM_NOTIFY_AUTH_REQUIRED:
            case STREAM_NOTIFY_COMPLETED:
            case STREAM_NOTIFY_FAILURE:
            case STREAM_NOTIFY_AUTH_RESULT:
            default:
                $this->dump($notification_code, $severity, $message, $message_code, $bytes_transferred, $bytes_max);
                break;

            case STREAM_NOTIFY_REDIRECTED:
                $this->message("Being redirected to: " . $message);
                break;

            case STREAM_NOTIFY_CONNECT:
                $this->message("Connected...");
                break;

            case STREAM_NOTIFY_FILE_SIZE_IS:
                $this->message("Got the filesize: " . $bytes_max);
                break;

            case STREAM_NOTIFY_MIME_TYPE_IS:
                $this->message("Found the mime-type: " . $message);
                break;

            case STREAM_NOTIFY_PROGRESS:
                $this->message("Made some progress, downloaded " . $bytes_transferred . " so far");
                break;
        }
    }
}