bug #46931 Flush backend output buffer after closing. (bradjones1)

fabpot · fabpot · commit 92c7e6ea7c5a · 2022-07-16T13:26:27.000+02:00
This PR was merged into the 4.4 branch. Discussion ---------- Flush backend output buffer after closing. | Q | A | ------------- | --- | Branch? | 4.4 | Bug fix? | ~~no~~ yes | New feature? | no | Deprecations? | no | Tickets | N/A | License | MIT | Doc PR | N/A Currently, `Response::send()` does some backend/server specific shutdown, with the default case being closing userland output buffers. PHP's output buffering may or may not be `On` by default. I recently discovered in the course of debugging my Drupal 9 project that closing output buffers may not be enough to flush the response's content to the client. In my case, output buffering wasn't enabled at all, making `Response::closeOutputBuffers()` a no-op. In either case, it appears necessary to also call `flush()`. This is important if the calling script/framework [wishes to perform additional work after sending the request but before shutting down](https://www.drupal.org/project/drupal/issues/3295790). According to the [PHP docs for flush()](https://www.php.net/manual/en/function.flush.php), this seems to be necessary in addition to closing all active output buffers (if used.) > Flushes the system write buffers of PHP and whatever backend PHP is using (CGI, a web server, etc). This attempts to push current output all the way to the browser with a few caveats. > > flush() may not be able to override the buffering scheme of your web server and it has no effect on any client-side buffering in the browser. It also doesn't affect PHP's userspace output buffering mechanism. This means ob_flush() should be called before flush() to flush the output buffers if they are in use. If it is Symfony's intent that the "final" `flush()` call be done by the implementing code/extending framework, it would be good to explicitly note that. Commits ------- d78b586 Flush with flush() after ob_end_flush()
diff --git a/src/Symfony/Component/HttpFoundation/Response.php b/src/Symfony/Component/HttpFoundation/Response.php
@@ -1236,6 +1236,7 @@ public static function closeOutputBuffers(int $targetLevel, bool $flush): void
         while ($level-- > $targetLevel && ($s = $status[$level]) && (!isset($s['del']) ? !isset($s['flags']) || ($s['flags'] & $flags) === $flags : $s['del'])) {
             if ($flush) {
                 ob_end_flush();
+                flush();
             } else {
                 ob_end_clean();
             }

Original file line number	Diff line number	Diff line change
`@@ -1236,6 +1236,7 @@ public static function closeOutputBuffers(int $targetLevel, bool $flush): void`
`1236`	`1236`	`while ($level-- > $targetLevel && ($s = $status[$level]) && (!isset($s['del']) ? !isset($s['flags']) \|\| ($s['flags'] & $flags) === $flags : $s['del'])) {`
`1237`	`1237`	`if ($flush) {`
`1238`	`1238`	`ob_end_flush();`
	`1239`	`+ flush();`
`1239`	`1240`	`} else {`
`1240`	`1241`	`ob_end_clean();`
`1241`	`1242`	`}`