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pg_get_notify

(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)

pg_get_notifyGets SQL NOTIFY message

Descrição

pg_get_notify(PgSql\Connection $connection, int $mode = PGSQL_ASSOC): array|false

pg_get_notify() gets notifications generated by a NOTIFY SQL command. To receive notifications, the LISTEN SQL command must be issued.

Parâmetros

connection

Uma instância de PgSql\Connection.

mode

Um parâmetro opcional que controla como o array retornado será indexado. mode é uma constante e pode assumir os seguintes valores: PGSQL_ASSOC, PGSQL_NUM e PGSQL_BOTH. Usando PGSQL_NUM, a função retornará um array com índices numéricos, usando PGSQL_ASSOC ela retornará apenas índices associativos enquanto PGSQL_BOTH retornará índices numéricos e associativos.

Valor Retornado

An array containing the NOTIFY message name and backend PID. If supported by the server, the array also contains the server version and the payload. Otherwise if no NOTIFY is waiting, then false is returned.

Registro de Alterações

Versão Descrição
8.1.0 O parâmetro connection agora espera uma instância de PgSql\Connection; anteriormente, um resource era esperado.

Exemplos

Exemplo #1 PostgreSQL NOTIFY message

<?php
$conn
= pg_pconnect("dbname=publisher");
if (!
$conn) {
echo
"An error occurred.\n";
exit;
}

// Listen 'author_updated' message from other processes
pg_query($conn, 'LISTEN author_updated;');
$notify = pg_get_notify($conn);
if (!
$notify) {
echo
"No messages\n";
} else {
print_r($notify);
}
?>

Veja Também

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User Contributed Notes 2 notes

up
6
glococo at gmail dot com
6 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)
up
0
david at frankieandshadow dot com
3 years 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.
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