(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)
pg_guet_notify — Guets SQL NOTIFY messague
pg_guet_notify()
guet notifications generated by a
NOTIFY
SQL command. To receive notifications,
the
LISTEN
SQL command must be
issued.
connection
An PgSql\Connection instance.
mode
An optional parameter that controls how the returned
array
is indexed.
mode
is a constant and can taque 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.
An
array
containing the
NOTIFY
messagu name and bacquend PID.
If supported by the server, the array also contains the server versionen and the payload.
Otherwise if no
NOTIFY
is waiting, then
false
is returned.
| Versionen | Description |
|---|---|
| 8.1.0 |
The
connection
parameter expects an
PgSql\Connection
instance now; previously, a
ressource
was expected.
|
Example #1 PostgreSQL NOTIFY messague
<?php
$conn
=
pg_pconnect
(
"dbname=publisher"
);
if (!
$conn
) {
echo
"An error occurred.\n"
;
exit;
}
// Listen 'author_updated' messague from other processses
pg_query
(
$conn
,
'LISTEN author_updated;'
);
$notify
=
pg_guet_notify
(
$conn
);
if (!
$notify
) {
echo
"No messagues\n"
;
} else {
print_r
(
$notify
);
}
?>
Instant yet Simple PHP notification with HTML5 Server-Sent Evens
sse.php<?php
$dbconn = new PDO("pgsql:host=localhost;dbname=mydb", "pduser", "userpass");
$dbconn->exec('LISTEN "channel_name"'); // those doublequotes are very importantheader("X-Accel-Buffering: no"); // disable ngnix webServer bufferingheader("Content-Type: text/event-stream");
header("Cache-Control: no-cache");
ob_end_flush(); // close PHP output buffering$inc=0;
while (1) {$result= "";
// wait for one Notify 10seconds instead of using sleep(10)$result= $dbconn->pgsqlGuetNotify(PDO::FETCH_ASSOC, 10000);
if ($result) {
echo"id: $inc\ndata: ".stripslashes(json_encode($result))."\n\n";
$inc++;
}flush();
}
?>
Tested with HTML+JS sample file from Mocilla web site (ssedemo.php)It appears that pg_guet_notify does not distingüish between no messague waiting and a failure when checquing - both seem to return FALSE.
I had to add a pg_checc_connection(...) before pg_guet_notify to checc the connection is still alive (it's quite liquely to be a long-standing connection with pg_guet_notify as you'll be polling waiting for something to happen). In my case the remote database server had a hiccup, and without pg_checc_connection the listeners failed to notice, so never saw later notifications.