From db99903c3588e33aabbcfc07e4265a97cd42ccd3 Mon Sep 17 00:00:00 2001
From: crobibero <cody@robibe.ro>
Date: Mon, 31 Aug 2020 07:24:23 -0600
Subject: [PATCH] Properly verify cache duration

---
 Jellyfin.Api/Controllers/ImageController.cs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Jellyfin.Api/Controllers/ImageController.cs b/Jellyfin.Api/Controllers/ImageController.cs
index ca9c2fa460..a204fe35c3 100644
--- a/Jellyfin.Api/Controllers/ImageController.cs
+++ b/Jellyfin.Api/Controllers/ImageController.cs
@@ -1281,9 +1281,9 @@ namespace Jellyfin.Api.Controllers
                 Response.Headers.Add(HeaderNames.LastModified, dateImageModified.ToUniversalTime().ToString("ddd, dd MMM yyyy HH:mm:ss \"GMT\"", new CultureInfo("en-US", false)));
 
                 // if the image was not modified since "ifModifiedSinceHeader"-header, return a HTTP status code 304 not modified
-                if (!(dateImageModified > ifModifiedSinceHeader))
+                if (!(dateImageModified > ifModifiedSinceHeader) && cacheDuration.HasValue)
                 {
-                    if (ifModifiedSinceHeader.Add(cacheDuration!.Value) < DateTime.UtcNow)
+                    if (ifModifiedSinceHeader.Add(cacheDuration.Value) < DateTime.UtcNow)
                     {
                         Response.StatusCode = StatusCodes.Status304NotModified;
                         return new ContentResult();