A callback function for the notification context parameter

- « stream_isatty

- stream_register_wrapper »

- PHP Manual
- Stream Functions
- A callback function for the notification context parameter

# stream_notification_callback

(PHP 5 >= 5.2.0, PHP 7, PHP 8)

stream_notification_callback — A callback function for the `notification` context parameter

### Description

stream_notification_callback(
int `$notification_code`,
int `$severity`,
?string `$message`,
int `$message_code`,
int `$bytes_transferred`,
int `$bytes_max`
): void

A callable function, used by the notification context parameter, called during an event.

> Note:

> This is not a real function, only a prototype of how the function should be.

### Parameters

`notification_code`

  One of the `STREAM_NOTIFY_*` notification constants.

`severity`

  One of the `STREAM_NOTIFY_SEVERITY_*` notification constants.

`message`

  Passed if a descriptive message is available for the event.

`message_code`

  Passed if a descriptive message code is available for the event.

  The meaning of this value is dependent on the specific wrapper in use.

`bytes_transferred`

  If applicable, the `bytes_transferred` will be populated.

`bytes_max`

  If applicable, the `bytes_max` will be populated.

### Return Values

No value is returned.

### Changelog

Version | Description
--- | ---
8.3.0 | Support for `STREAM_NOTIFY_COMPLETED` implemented, earlier PHP versions would never trigger this notification.

### Examples

Example #1 stream_notification_callback() example

    <?php
    function stream_notification_callback($notification_code, $severity, $message, $message_code, $bytes_transferred, $bytes_max) {

        switch($notification_code) {
            case STREAM_NOTIFY_RESOLVE:
            case STREAM_NOTIFY_AUTH_REQUIRED:
            case STREAM_NOTIFY_COMPLETED:
            case STREAM_NOTIFY_FAILURE:
            case STREAM_NOTIFY_AUTH_RESULT:
                var_dump($notification_code, $severity, $message, $message_code, $bytes_transferred, $bytes_max);
                /* Ignore */
                break;

            case STREAM_NOTIFY_REDIRECTED:
                echo "Being redirected to: ", $message;
                break;

            case STREAM_NOTIFY_CONNECT:
                echo "Connected...";
                break;

            case STREAM_NOTIFY_FILE_SIZE_IS:
                echo "Got the filesize: ", $bytes_max;
                break;

            case STREAM_NOTIFY_MIME_TYPE_IS:
                echo "Found the mime-type: ", $message;
                break;

            case STREAM_NOTIFY_PROGRESS:
                echo "Made some progress, downloaded ", $bytes_transferred, " so far";
                break;
        }
        echo "\n";
    }

    $ctx = stream_context_create();
    stream_context_set_params($ctx, array("notification" => "stream_notification_callback"));

    file_get_contents("http://php.net/contact", false, $ctx);
    ?>

The above example will output something similar to:

    Connected...
    Found the mime-type: text/html; charset=utf-8
    Being redirected to: http://no.php.net/contact
    Connected...
    Got the filesize: 0
    Found the mime-type: text/html; charset=utf-8
    Being redirected to: http://no.php.net/contact.php
    Connected...
    Got the filesize: 4589
    Found the mime-type: text/html;charset=utf-8
    Made some progress, downloaded 0 so far
    Made some progress, downloaded 0 so far
    Made some progress, downloaded 0 so far
    Made some progress, downloaded 1440 so far
    Made some progress, downloaded 2880 so far
    Made some progress, downloaded 4320 so far
    Made some progress, downloaded 5760 so far
    Made some progress, downloaded 6381 so far
    Made some progress, downloaded 7002 so far

Example #2 Simple progressbar for commandline download client

    <?php
    function usage($argv) {
        echo "Usage:\n";
        printf("\tphp %s <http://example.com/file> <localfile>\n", $argv[0]);
        exit(1);
    }

    function stream_notification_callback($notification_code, $severity, $message, $message_code, $bytes_transferred, $bytes_max) {
        static $filesize = null;

        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:
            /* Ignore */
            break;

        case STREAM_NOTIFY_REDIRECTED:
            echo "Being redirected to: ", $message, "\n";
            break;

        case STREAM_NOTIFY_CONNECT:
            echo "Connected...\n";
            break;

        case STREAM_NOTIFY_FILE_SIZE_IS:
            $filesize = $bytes_max;
            echo "Filesize: ", $filesize, "\n";
            break;

        case STREAM_NOTIFY_MIME_TYPE_IS:
            echo "Mime-type: ", $message, "\n";
            break;

        case STREAM_NOTIFY_PROGRESS:
            if ($bytes_transferred > 0) {
                if (!isset($filesize)) {
                    printf("\rUnknown filesize.. %2d kb done..", $bytes_transferred/1024);
                } else {
                    $length = (int) (($bytes_transferred/$filesize)*100);
                    printf("\r[%-100s] %d%% (%2d/%2d kb)", str_repeat("=", $length). ">", $length, ($bytes_transferred/1024), $filesize/1024);
                }
            }
            break;
        }
    }

    isset($argv[1], $argv[2]) or usage($argv);

    $ctx = stream_context_create();
    stream_context_set_params($ctx, array("notification" => "stream_notification_callback"));

    $fp = fopen($argv[1], "r", false, $ctx);
    if (is_resource($fp) && file_put_contents($argv[2], $fp)) {
        echo "\nDone!\n";
        exit(0);
    }

    $err = error_get_last();
    echo "\nErrrrrorr..\n", $err["message"], "\n";
    exit(1);
    ?>

Executing the example above with: `php -n fetch.php http://no2.php.net/get/php-5-LATEST.tar.bz2/from/this/mirror php-latest.tar.bz2` will output something similar too:

    Connected...
    Mime-type: text/html; charset=utf-8
    Being redirected to: http://no2.php.net/distributions/php-5.2.5.tar.bz2
    Connected...
    Filesize: 7773024
    Mime-type: application/octet-stream
    [========================================>                                                           ] 40% (3076/7590 kb)

### See Also

- Context parameters