pg_get_notify

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

pg_get_notify — Lee el mensaje SQL NOTIFY

Descripción

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

pg_get_notify() recibe el mensaje de NOTIFY enviado por un comando SQL NOTIFY. Para leer el mensaje asociado, se debe utilizar el comando LISTEN.

Parámetros

connection: An PgSql\Connection instance.
mode: An optional parameter that controls how the returned array is indexed. mode is a constant and can take the following values: PGSQL_ASSOC, PGSQL_NUM and PGSQL_BOTH. Using PGSQL_NUM, the function will return an array with numerical indices, using PGSQL_ASSOC it will return only associative indices while PGSQL_BOTH will return both numerical and associative indices.

Valores devueltos

Un array que contiene el nombre del mensaje NOTIFY. Si el servidor lo soporta, el array contiene también la versión del servidor y la carga útil (payload). De lo contrario, si no hay ningún NOTIFY pendiente, se devolverá false.

Historial de cambios

Versión	Descripción
8.1.0	The `connection` parameter expects an PgSql\Connection instance now; previously, a recurso was expected.

Ejemplos

Ejemplo #1 Ejemplo con pg_get_notify()

<?php
$conn = pg_pconnect("dbname=publisher");
if (!$conn) {
  echo "Se ha producido un error.\n";
  exit;
}

// escucha el mensaje 'author_updated' de otros procesos
pg_query($conn, 'LISTEN author_updated;');
$notify = pg_get_notify($conn);
if (!$notify) {
  echo "Ningún mensaje\n";
} else {
  print_r($notify);
}
?>

Ver también

pg_get_pid() - Obtiene la ID del proceso del backend

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User Contributed Notes 2 notes

down

glococo at gmail dot com ¶

8 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)

down

david at frankieandshadow dot com ¶

4 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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