From d4ce68e0f967c9a7758254efbf168798decbbbe9 Mon Sep 17 00:00:00 2001
From: Joas Schilling <coding@schilljs.com>
Date: Mon, 2 Feb 2026 11:43:39 +0100
Subject: [PATCH] perf(response): Flush requests early to clients

If not, the response will wait for async actions, e.g. HTTP requests from
IClientService, to be finished before returning. This is not desired in
many cases with e.g. with notifications.

Signed-off-by: Joas Schilling <coding@schilljs.com>
---
 lib/private/AppFramework/App.php          |  5 +++++
 lib/public/AppFramework/Http/Response.php | 22 ++++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/lib/private/AppFramework/App.php b/lib/private/AppFramework/App.php
index 7bf32852209..1a82fe58345 100644
--- a/lib/private/AppFramework/App.php
+++ b/lib/private/AppFramework/App.php
@@ -213,5 +213,10 @@ class App {
 				$io->setOutput($output);
 			}
 		}
+
+		if ($response->getFlushEarly()) {
+			ob_flush();
+			flush();
+		}
 	}
 }
diff --git a/lib/public/AppFramework/Http/Response.php b/lib/public/AppFramework/Http/Response.php
index 6edd32a1f8b..b602776567b 100644
--- a/lib/public/AppFramework/Http/Response.php
+++ b/lib/public/AppFramework/Http/Response.php
@@ -66,6 +66,7 @@ class Response {
 
 	/** @var bool */
 	private $throttled = false;
+	private bool $flushEarly = true;
 	/** @var array */
 	private $throttleMetadata = [];
 
@@ -412,4 +413,25 @@ class Response {
 	public function isThrottled() {
 		return $this->throttled;
 	}
+
+	/**
+	 * Request the response should be flushed to the connected client immediately
+	 *
+	 * @since 34.0.0
+	 */
+	public function setFlushEarly(bool $flushEarly): void {
+		$this->flushEarly = $flushEarly;
+	}
+
+	/**
+	 * Whether the response should be flushed to the connected client immediately
+	 *
+	 * If not, the response will wait for async actions, e.g. HTTP requests from
+	 * IClientService, to be finished before returning.
+	 *
+	 * @since 34.0.0
+	 */
+	public function getFlushEarly(): bool {
+		return $this->flushEarly;
+	}
 }