pg_get_notify

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

    pg_get_notify — Gets SQL NOTIFY message

    Опис

    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.

    Параметри

    connection

    Примірник PgSql\Connection.

    mode

    Необов'язковий параметр, яким вказується спосіб індексування масиву (array). mode може мати значення однієї з констант: PGSQL_ASSOC, PGSQL_NUM або PGSQL_BOTH. Якщо задано PGSQL_NUM, то функція поверне масив з числовими індексами; якщо PGSQL_ASSOC, то з асоціативними індексами; якщо PGSQL_BOTH, то і з числовими, і з асоціативними індексами.

    Значення, що повертаються

    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.

    Журнал змін

    Версія Опис
    8.1.0 Тепер параметр connection має бути примірником PgSql\Connection. Раніше очікувався resource.

    Приклади

    Приклад #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

    up
    5
    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)
    up
    0
    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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