From d042f3194f4f2cda68c090ac7855aa368e481977 Mon Sep 17 00:00:00 2001
From: Nick Craig-Wood <nick@craig-wood.com>
Date: Wed, 24 Mar 2021 17:04:05 +0000
Subject: [PATCH] b2: fix html files downloaded via cloudflare

When reading files from B2 via cloudflare using --b2-download-url
cloudflare strips the Content-Length headers (presumably so it can
inject stuff into the body).

This caused rclone to think the file was corrupted as the length
didn't match.

The patch uses the old length read from the listing if there is no
Content-Length.

See: https://forum.rclone.org/t/b2-cloudflare-error-directory-not-found/23026
---
 backend/b2/b2.go | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/backend/b2/b2.go b/backend/b2/b2.go
index b5690a99e..eccb06441 100644
--- a/backend/b2/b2.go
+++ b/backend/b2/b2.go
@@ -1744,6 +1744,13 @@ func (o *Object) getOrHead(ctx context.Context, method string, options []fs.Open
 		ContentType:     resp.Header.Get("Content-Type"),
 		Info:            Info,
 	}
+	// When reading files from B2 via cloudflare using
+	// --b2-download-url cloudflare strips the Content-Length
+	// headers (presumably so it can inject stuff) so use the old
+	// length read from the listing.
+	if info.Size < 0 {
+		info.Size = o.size
+	}
 	return resp, info, nil
 }