From cb2a6d688fd48e9f4f903df0d45bfaf184b3e08f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?C=C3=B4me=20Chilliet?= <come.chilliet@nextcloud.com>
Date: Mon, 4 Sep 2023 14:56:06 +0200
Subject: [PATCH] Detect aborted connection in OC\Files\View and stop writing
 data to the  output buffer
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Signed-off-by: Côme Chilliet <come.chilliet@nextcloud.com>
---
 lib/private/Files/View.php      | 12 ++++++++++--
 lib/private/legacy/OC_Files.php |  3 ---
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/lib/private/Files/View.php b/lib/private/Files/View.php
index 28b2cf67640..a6b802ffe85 100644
--- a/lib/private/Files/View.php
+++ b/lib/private/Files/View.php
@@ -428,6 +428,7 @@ class View {
 			$chunkSize = 524288; // 512 kB chunks
 			while (!feof($handle)) {
 				echo fread($handle, $chunkSize);
+				$this->checkConnectionStatus();
 				flush();
 			}
 			fclose($handle);
@@ -480,6 +481,7 @@ class View {
 						$len = $chunkSize;
 					}
 					echo fread($handle, $len);
+					$this->checkConnectionStatus();
 					flush();
 				}
 				return ftell($handle) - $from;
@@ -490,6 +492,14 @@ class View {
 		return false;
 	}
 
+
+	private function checkConnectionStatus(): void {
+		$connectionStatus = \connection_status();
+		if ($connectionStatus !== 0) {
+			throw new \RuntimeException("Connection lost. Status: $connectionStatus");
+		}
+	}
+
 	/**
 	 * @param string $path
 	 * @return mixed
@@ -1053,7 +1063,6 @@ class View {
 	public function fromTmpFile($tmpFile, $path) {
 		$this->assertPathLength($path);
 		if (Filesystem::isValidPath($path)) {
-
 			// Get directory that the file is going into
 			$filePath = dirname($path);
 
@@ -1809,7 +1818,6 @@ class View {
 	 * @return boolean
 	 */
 	private function targetIsNotShared(IStorage $targetStorage, string $targetInternalPath) {
-
 		// note: cannot use the view because the target is already locked
 		$fileId = (int)$targetStorage->getCache()->getId($targetInternalPath);
 		if ($fileId === -1) {
diff --git a/lib/private/legacy/OC_Files.php b/lib/private/legacy/OC_Files.php
index 6a3a44d6cc0..48e36dac2ce 100644
--- a/lib/private/legacy/OC_Files.php
+++ b/lib/private/legacy/OC_Files.php
@@ -238,9 +238,6 @@ class OC_Files {
 			OC::$server->getLogger()->logException($ex);
 			$l = \OC::$server->getL10N('lib');
 			$hint = method_exists($ex, 'getHint') ? $ex->getHint() : '';
-			if ($event && $event->getErrorMessage() !== null) {
-				$hint .= ' ' . $event->getErrorMessage();
-			}
 			\OC_Template::printErrorPage($l->t('Cannot download file'), $hint, 200);
 		}
 	}