Webrick WARN: "Could not determine content-length of response body"
Extracted from issue #19435:
Webrick WARNing in Redmine 3.0.1:
[2015-03-21 14:15:15] WARN Could not determine content-length of response body. Set content-length of the response or set Response#chunked = true
Happens for all attachments (even images) when trying to download them.
Download works as expected, but the filesize is unknown.
Seems as if the HTTP header can't be set.
This wasn't a problem in redmine 2.6