From: Dan Brown <redacted>
Date: Mon, 9 May 2022 14:25:06 +0000 (+0100)
Subject: Updated attachment download to check OB before cleaning it
X-Git-Tag: v22.04.2~1^2~2
X-Git-Url: http://source.bookstackapp.com/bookstack/commitdiff_plain/2a99e23e6d2dfa8898eb7e2a9be97cbe9b819b2c

Updated attachment download to check OB before cleaning it

Call to `ob_end_clean` would error if the environment did not use the
PHP `output_buffering` option. This adds an additional check and updates
the comment to be more specific to the exact scenario of the condition.
Tested with output_buffering=Off and output_buffering=4096

Closes #3415
---

diff --git a/app/Http/Controllers/Controller.php b/app/Http/Controllers/Controller.php
index c00ac938b..5b2221fc1 100644
--- a/app/Http/Controllers/Controller.php
+++ b/app/Http/Controllers/Controller.php
@@ -127,9 +127,11 @@ abstract class Controller extends BaseController
     protected function streamedDownloadResponse($stream, string $fileName): StreamedResponse
     {
         return response()->stream(function () use ($stream) {
-            // End & flush the output buffer otherwise we still seem to use memory.
+
+            // End & flush the output buffer, if we're in one, otherwise we still use memory.
+            // Output buffer may or may not exist depending on PHP `output_buffering` setting.
             // Ignore in testing since output buffers are used to gather a response.
-            if (!app()->runningUnitTests()) {
+            if (!empty(ob_get_status()) && !app()->runningUnitTests()) {
                 ob_end_clean();
             }