Magnolia: Range request doesn't serve content when cache filter enabled resulting in Facebook Sharing not to work - magnolia

Question

When sending an HTTP request with a Range header to Magnolia I get a Response with
Content-Length: 0:
curl -I -X GET \
http://localhost:8080/ \
-H 'Accept-Encoding: gzip, deflate' \
-H 'Cache-Control: no-cache' \
-H 'Range: bytes=0-2000'
HTTP/1.1 206
Set-Cookie: SID=C36D961EC92D152724BBCD0C34EC6536; Path=/; HttpOnly
X-Magnolia-Registration: Registered
Accept-Ranges: bytes
Cache-Control: no-cache, no-store, must-revalidate, max-age=0
ETag: 8B4901E7DD862E5E74287A0F538DCDDFEB78DE77
Content-Range: bytes 0-2000/23529
Content-Encoding: gzip
Vary: Accept-Encoding
Pragma: no-cache
Expires: Thu, 01 Jan 1970 00:00:00 GMT
Last-Modified: Thu, 19 Dec 2019 08:52:49 GMT
Content-Type: text/html;charset=UTF-8
Content-Length: 0
Date: Thu, 19 Dec 2019 08:52:49 GMT
However, when I disable the Magnolia Cache Module I get the expected response:
/server/filters/cache -> enabled: false
curl -I -X GET \
http://localhost:8080/ \
-H 'Accept-Encoding: gzip, deflate' \
-H 'Cache-Control: no-cache' \
-H 'Range: bytes=0-2000'
HTTP/1.1 206
Set-Cookie: SID=FF557EC1F0653E5CBD81A57D599091AE; Path=/; HttpOnly
X-Magnolia-Registration: Registered
Accept-Ranges: bytes
ETag: 2A9DE4F4B2ACDDE22BAC3C07784CD65693574B67
Content-Range: bytes 0-2000/2147483647
Content-Type: text/html;charset=UTF-8
Content-Length: 2001
Date: Thu, 19 Dec 2019 08:51:49 GMT
I got the problem that the Facebook crawler isn't able to detect any open graph meta tags when trying to crawl my website. I think the reason is the above described problem with sending range requests to Magnolia (What the Facebook crawler does).
My Open Graph tags are properly set (Working for opengraphcheck and Twitter Card Validator).
I'm using Magnolia 5.7.1.

Answer 1

The simplest work around is to configure request header voter to bypass cache when range header is present.
See RequestHeaderPatternSimpleVoter and/or RequestHeaderPatternRegexVoter for more details on how to set it, but I would still consider it workaround and not final solution.
It seems weird that such thing should be happening. Could you replicate it against e.g. https://demo.magnolia-cms.com?