pg_get_notify
(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)
pg_get_notify — Ping 数据库连接
说明
pg_get_notify(resource
$connection, int $result_type = ?): array
pg_get_notify() 取得 SQL 命令
NOTIFY
发送的通告消息。要接收通告消息，必须发送 SQL 命令
LISTEN。如果连接中有通告消息，则数组包含消息名并且返回后端的
PID。如果没有消息则返回 false。
参见 pg_get_pid()。
示例 #1 PostgreSQL NOTIFY 消息
<?php
$conn = pg_pconnect("dbname=publisher");
if (!$conn) {
echo "An error occured.\n";
exit;
}
// Listen 'author_updated' message from other processes
pq_query($conn, 'LISTEN author_updated;');
$notify = pg_get_notify($conn);
if (!$notify)
print("No messages\n");
else
print_r($notify);
?>
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User Contributed Notes 2 notes
glococo at gmail dot com ¶
5 years ago
Instant yet Simple PHP notification with HTML5 Server-Sent Events
sse.php
<?php
$dbconn = new PDO("pgsql:host=localhost;dbname=mydb", "pduser", "userpass");
$dbconn->exec('LISTEN "channel_name"'); // those doublequotes are very important
header("X-Accel-Buffering: no"); // disable ngnix webServer buffering
header("Content-Type: text/event-stream");
header("Cache-Control: no-cache");
ob_end_flush(); // close PHP output buffering
$inc=0;
while (1) {
$result = "";
// wait for one Notify 10seconds instead of using sleep(10)
$result = $dbconn->pgsqlGetNotify(PDO::FETCH_ASSOC, 10000);
if ( $result ) {
echo "id: $inc\ndata: ".stripslashes(json_encode($result))."\n\n";
$inc++;
}
flush();
}
?>
Tested with HTML+JS sample file from Mozilla web site (ssedemo.php)
david at frankieandshadow dot com ¶
1 year ago
It appears that pg_get_notify does not distinguish between no message waiting and a failure when checking - both seem to return FALSE.
I had to add a pg_check_connection(...) before pg_get_notify to check the connection is still alive (it's quite likely to be a long-standing connection with pg_get_notify as you'll be polling waiting for something to happen). In my case the remote database server had a hiccup, and without pg_check_connection the listeners failed to notice, so never saw later notifications.
备份地址：http://www.lvesu.com/blog/php/function.pg-get-notify.php