From c223c7598dcd44db9befcce8fb49c6dbbcfac36d Mon Sep 17 00:00:00 2001
From: tobi <31960611+tsmethurst@users.noreply.github.com>
Date: Sun, 12 Feb 2023 14:42:28 +0100
Subject: [PATCH] [bugfix] Set appropriate cache-control when using presigned
 s3 links (#1480)

---
 internal/api/fileserver/servefile.go | 7 ++++++-
 internal/processing/media/getfile.go | 3 +++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/internal/api/fileserver/servefile.go b/internal/api/fileserver/servefile.go
index cdd42a179..6b125debc 100644
--- a/internal/api/fileserver/servefile.go
+++ b/internal/api/fileserver/servefile.go
@@ -88,7 +88,12 @@ func (m *Module) ServeFile(c *gin.Context) {
 	}
 
 	if content.URL != nil {
-		// This is a non-local S3 file we're proxying to.
+		// This is a non-local S3 file we're redirecting to.
+		// Rewrite the cache control header to reflect the
+		// TTL of the generated signed link, instead of the
+		// default very long cache.
+		const cacheControl = "private,max-age=86400" // 24h
+		c.Header("Cache-Control", cacheControl)
 		c.Redirect(http.StatusFound, content.URL.String())
 		return
 	}
diff --git a/internal/processing/media/getfile.go b/internal/processing/media/getfile.go
index 9501706fb..9843d6714 100644
--- a/internal/processing/media/getfile.go
+++ b/internal/processing/media/getfile.go
@@ -232,10 +232,13 @@ func (p *processor) getEmojiContent(ctx context.Context, fileName string, owning
 }
 
 func (p *processor) retrieveFromStorage(ctx context.Context, storagePath string, content *apimodel.Content) (*apimodel.Content, gtserror.WithCode) {
+	// If running on S3 storage with proxying disabled then
+	// just fetch a pre-signed URL instead of serving the content.
 	if url := p.storage.URL(ctx, storagePath); url != nil {
 		content.URL = url
 		return content, nil
 	}
+
 	reader, err := p.storage.GetStream(ctx, storagePath)
 	if err != nil {
 		return nil, gtserror.NewErrorNotFound(fmt.Errorf("error retrieving from storage: %s", err))