mysqli::ping

mysqli_ping

(PHP 5, PHP 7, PHP 8)

mysqli::ping -- mysqli_ping — Pings a server connection, or tries to reconnect if the connection has gone down

Увага

Ця функція ЗАСТАРІЛА, починаючи з PHP 8.4.0. Вкрай не рекомендується на неї покладатися.

Опис

Об'єктно-орієнтований стиль

#[\Deprecated]
public mysqli::ping(): bool

Процедурний стиль

#[\Deprecated]
mysqli_ping(mysqli $mysql): bool

Checks whether the connection to the server is working. If it has gone down and global option mysqli.reconnect is enabled, an automatic reconnection is attempted.

Зауваження: The php.ini setting mysqli.reconnect is ignored by the mysqlnd driver, so automatic reconnection is never attempted.

This function can be used by clients that remain idle for a long while, to check whether the server has closed the connection and reconnect if necessary.

Параметри

mysql: Тільки процедурний стиль: об'єкт mysqli, якого повертає функція mysqli_connect() або mysqli_init()

Значення, що повертаються

Повертає true у разі успіху або false в разі помилки.

Помилки/виключення

Якщо увімкнені звіти про помилки mysqli (MYSQLI_REPORT_ERROR) і запитана операція не виконалась, буде виведено попередження, але якщо встановлено режим MYSQLI_REPORT_STRICT, буде викинуто виключення mysqli_sql_exception.

Журнал змін

Версія	Опис
8.4.0	Both mysqli::ping() and mysqli_ping() are now deprecated. The `reconnect` feature has not been available as of PHP 8.2.0, making this function obsolete.

Приклади

Приклад #1 mysqli::ping() example

Об'єктно-орієнтований стиль

<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");

/* check connection */
if ($mysqli->connect_errno) {
    printf("Connect failed: %s\n", $mysqli->connect_error);
    exit();
}

/* check if server is alive */
if ($mysqli->ping()) {
    printf ("Our connection is ok!\n");
} else {
    printf ("Error: %s\n", $mysqli->error);
}

/* close connection */
$mysqli->close();
?>

Процедурний стиль

<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");

/* check connection */
if (mysqli_connect_errno()) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    exit();
}

/* check if server is alive */
if (mysqli_ping($link)) {
    printf ("Our connection is ok!\n");
} else {
    printf ("Error: %s\n", mysqli_error($link));
}

/* close connection */
mysqli_close($link);
?>

Подані вище приклади виведуть:

Our connection is ok!

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User Contributed Notes 3 notes

down

jay at grooveshark dot com ¶

11 years ago

This does not work with mysqlnd and is marked as wontfix: https://bugs.php.net/bug.php?id=52561

down

root at jusme dot org ¶

10 years ago

As jay at grooveshark dot com very helpfully pointed out, the mysqlnd driver which is becoming pretty standard does not obey reconnect commands. If you have a DB wrapper class (which hopefully you do) you can implement your own version of ping() such as:

<?php

class db extends mysqli
{
    private $db_host;
    private $db_user;
    private $db_pass;
    private $db_name;
    private $persistent;

    public function __construct($db_host, $db_user, $db_pass, $db_name, $persistent = true)
    {
        $this->db_host = $db_host;
        $this->db_user = $db_user;
        $this->db_pass = $db_pass;
        $this->db_name = $db_name;
        $this->persistent = $persistent;

        parent::init();
        parent::options(MYSQLI_OPT_CONNECT_TIMEOUT, 1);
        @parent::real_connect(($this->persistent ? 'p:' : '') . $this->db_host, $this->db_user, $this->db_pass, $this->db_name);

        if ($this->connect_errno)
            die("All DB servers down!\n");
    }

    public function ping()
    {
        @parent::query('SELECT LAST_INSERT_ID()');

        if ($this->errno == 2006)
            $this->__construct($this->db_host, $this->db_user, $this->db_pass, $this->db_name, $this->persistent);
    }
...
}

$db = new db(DB_HOST, DB_USER, DB_PASS, DB_NAME);
// Some code that potentially takes a really long time to execute goes here
// Ping for safety to try to gracefully reconnect
$db->ping();
// Now we should be able to run queries again
$db->query('SELECT LAST_INSERT_ID()');

?>

If you wanted you could even put "$this->ping();" at the top of db::query() to avoid any explicit reconnection calls but I wouldn't recommend it due to the (slight) overhead of running the cheap "SELECT LAST_INSERT_ID()" query every time prior to running your real intended query. There are probably even cheaper queries to run in favor of "SELECT LAST_INSERT_ID()" but it was the first that came to mind and is cheap enough for most purposes since you shouldn't be calling ping() a whole bunch anyway.

down

snooops84 at googlemail dot com ¶

10 years ago

The behaviour about the option mysqli.reconnect is default set to Off at Debian PHP Packages. So i would recommend to update the first line description about the recommendation at the option mysqli.reconnect. (practice note ;))

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