Pdo\Pgsql::getNotify

(PHP 8 >= 8.4.0)

Pdo\Pgsql::getNotify — Get asynchronous notification

说明

public Pdo\Pgsql::getNotify(int $fetchMode = PDO::FETCH_DEFAULT, int $timeoutMilliseconds = 0): array|false

Returns a result set representing a pending asynchronous notification.

参数

fetchMode

The format the result set should be returned as, one of the following constants:

timeoutMilliseconds

The length of time to wait for a response, in milliseconds.

返回值

If one or more notifications is pending, returns a single row, with fields message and pid, otherwise returns false.

错误／异常

A ValueError is thrown if fetchMode is not one of the valid PDO::FETCH_* constants.

A ValueError is thrown if timeoutMilliseconds is less than 0.

A E_WARNING is raised when timeoutMilliseconds is greater than the value that can be contained in a signed 32-bit integer, in which case it will be the maximum value of a signed 32-bit integer.

参见

PDO::query() - 预处理并执行没有占位符的 SQL 语句
PDOStatement::fetch() - 从结果集中获取下一行
PDOStatement::fetchAll() - 从结果集中获取剩余的行

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sage at sage dot sk ¶

9 days ago

This page needs an example to understand that you **need** to explicitly call LISTEN before using getNotify, like shown in https://www.php.net/manual/en/function.pg-get-notify.php

<?php

$db = new PDO($dsn, $user, $password, $options);
$db->query('LISTEN test');
$notification = $db->pgsqlGetNotify(PDO::FETCH_ASSOC, 10000);

// or

$db = new Pdo\Pgsql($dsn, $user, $password, $options);
$db->query('LISTEN test');
$notification = $db->getNotify(PDO::FETCH_ASSOC, 10000);

// now you can call NOTIFY elsewhere
// PG> NOTIFY test, 'payload string';
var_dump($notification);

?>

array(3) {
  ["message"]=>
  string(4) "test"
  ["pid"]=>
  int(123565)
  ["payload"]=>
  string(14) "payload string"
}

If you called NOTIFY before calling LISTEN, nothing will be returned!

You receive the first notification only, and you have to call getNotify again. And call LISTEN again if DB connection drops.