pg_lo_read_all
(PHP 4 >= 4.2.0, PHP 5, PHP 7)
pg_lo_read_all — Читает содержимое большого объекта и посылает напрямую в броузер
Описание
int pg_lo_read_all
( resource
$large_object
)pg_lo_read_all() читает большой объект и посылает данные напрямую в броузер после отправки всех необходимых заголовков. Используется в основном для пересылки двоичных данных, таких как изображения или звук.
Операции с использованием интерфейса больших объектов необходимо заключать в блок транзакции.
Замечание:
Прежнее название функции: pg_loreadall().
Список параметров
-
large_object -
Ресурс большого объекта (LOB) PostgreSQL, возвращаемый функцией pg_lo_open().
Возвращаемые значения
Количество прочитанных байт, либо FALSE в случае ошибки.
Примеры
Пример #1 Пример использования pg_lo_read_all()
<?php
header('Content-type: image/jpeg');
$image_oid = 189762345;
$database = pg_connect("dbname=jacarta");
pg_query($database, "begin");
$handle = pg_lo_open($database, $image_oid, "r");
pg_lo_read_all($handle);
pg_query($database, "commit");
?>
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Коментарии
// remember, large objects must be obtained from within a transaction
pg_query ($dbconn, "begin");
// "assume" for this example that the large object resource number of the zipped file is "17899"
$lo_oid = 17899;
$handle_lo = pg_lo_open($dbconn,$lo_oid,"r") or die("<h1>Error.. can't get handle</h1>");
//headers to send to the browser before beginning the binary download
header('Accept-Ranges: bytes');
header('Content-Length: 32029974'); //this is the size of the zipped file
header('Keep-Alive: timeout=15, max=100');
header('Content-type: Application/x-zip');
header('Content-Disposition: attachment; filename="superjob.zip"');
pg_lo_read_all($handle_lo) or
die("<h1>Error, can't read large object.</h1>");
// committing the data transaction
pg_query ($dbconn, "commit");
Pay attention that if you omit the "length" parameter it will read a 8192 bytes object regardless to its real dimensions. If you want to use this function think to save the object size somewhere (usually a field in its table) before reading the object. Alternatively use the pg_lo_readall function.