From e43c1d5c44c826f8c8fb831abe07cf512a3d6a89 Mon Sep 17 00:00:00 2001
From: miqrogroove <1371835+miqrogroove@users.noreply.github.com>
Date: Wed, 4 Sep 2024 17:09:10 -0400
Subject: [PATCH] Enabled client-side caching in the IIIF service.

Arbitrary value of 1 hour allows web browsers to close and re-open overlay viewers without requesting image tiles every time.

Complements providence/pull/1612
---
 app/lib/Service/IIIFService.php | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/app/lib/Service/IIIFService.php b/app/lib/Service/IIIFService.php
index 443fa311ce..7f17311c5d 100644
--- a/app/lib/Service/IIIFService.php
+++ b/app/lib/Service/IIIFService.php
@@ -43,6 +43,8 @@ class IIIFService {
 	 * @throws Exception
 	 */
 	public static function dispatch(string $identifier, RequestHTTP $request, ResponseHTTP $response) {
+		$response->addHeader('Cache-Control', 'max-age=3600, private', true); // Cache all responses for 1 hour.
+
 		$va_path = array_filter(array_slice(explode("/", $request->getPathInfo()), 3), 'strlen');
 		$vs_key = $identifier."/".join("/", $va_path);