pg_get_notify

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

pg_get_notify — Gets SQL NOTIFY message

Description

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.

Parameters

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.

Return Values

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.

Changelog

Version	Description
8.1.0	The `connection` parameter expects an PgSql\Connection instance now; previously, a resource was expected.

Examples

Example #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);
}
?>

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User Contributed Notes 2 notes

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glococo at gmail dot com ¶

7 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)