From 0cec4753d8afaa5673eba526c121d8b1e1062a5d Mon Sep 17 00:00:00 2001
From: Laurent Cozic <laurent@cozic.net>
Date: Tue, 17 Aug 2021 23:29:46 +0100
Subject: [PATCH] Server: Fixes #5328: Filenames with non-ascii characters
 could not be downloaded from published note

---
 packages/lib/path-utils.ts                 | 8 ++++++++
 packages/server/src/routes/index/shares.ts | 7 ++++++-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/packages/lib/path-utils.ts b/packages/lib/path-utils.ts
index 49f877451..2a9091191 100644
--- a/packages/lib/path-utils.ts
+++ b/packages/lib/path-utils.ts
@@ -65,6 +65,14 @@ for (let i = 0; i < 32; i++) {
 
 const friendlySafeFilename_blackListNames = ['.', '..', 'CON', 'PRN', 'AUX', 'NUL', 'COM1', 'COM2', 'COM3', 'COM4', 'COM5', 'COM6', 'COM7', 'COM8', 'COM9', 'LPT1', 'LPT2', 'LPT3', 'LPT4', 'LPT5', 'LPT6', 'LPT7', 'LPT8', 'LPT9'];
 
+// The goal of this function is to provide a safe filename, that should work in
+// any filesystem, but that's still user friendly, in particular because it
+// supports any charset - Chinese, Russian, etc.
+//
+// "Safe" however doesn't mean it can be safely inserted in any content (HTML,
+// Markdown, etc.) - it still needs to be encoded by the calling code according
+// to the context.
+
 export function friendlySafeFilename(e: string, maxLength: number = null, preserveExtension: boolean = false) {
 	// Although Windows supports paths up to 255 characters, but that includes the filename and its
 	// parent directory path. Also there's generally no good reason for dir or file names
diff --git a/packages/server/src/routes/index/shares.ts b/packages/server/src/routes/index/shares.ts
index 5741c85e4..19e4852fa 100644
--- a/packages/server/src/routes/index/shares.ts
+++ b/packages/server/src/routes/index/shares.ts
@@ -21,6 +21,11 @@ async function renderItem(context: AppContext, item: Item, share: Share): Promis
 	};
 }
 
+function createContentDispositionHeader(filename: string) {
+	const encoded = encodeURIComponent(friendlySafeFilename(filename));
+	return `attachment; filename*=UTF-8''${encoded}; filename="${encoded}"`;
+}
+
 const router: Router = new Router(RouteType.Web);
 
 router.public = true;
@@ -46,7 +51,7 @@ router.get('shares/:id', async (path: SubPath, ctx: AppContext) => {
 	ctx.response.body = result.body;
 	ctx.response.set('Content-Type', result.mime);
 	ctx.response.set('Content-Length', result.size.toString());
-	if (result.filename) ctx.response.set('Content-disposition', `attachment; filename="${friendlySafeFilename(result.filename)}"`);
+	if (result.filename) ctx.response.set('Content-disposition', createContentDispositionHeader(result.filename));
 	return new Response(ResponseType.KoaResponse, ctx.response);
 }, RouteType.UserContent);