Behind HTTPS Load Balancer, Renders HTTP load of JS to Browser

Re-rolling patch #6 for 8.x-1.2

Hi,
I created a patch to use relative url. The iframe url is generated with file_url_generator service.
The patch replace generateAbsoluteString method to generateString.

In my case works Behind HTTPS Load Balancer.

Props to @marco.aresu the latest patch works a treat when using Varnish. We were encountering the same issue. Patch resolves the problem right away.

I tested patch from marco.aresu (#10) and it works but page attachments remain in http. For the moment I used hook_page_attachments_alter to correct this with a str_replace("http:", "https:", $url) looping through
$attachments['#attached']['html_head_link'][1][0]['href']
I suppose the other patches don't correct this either.

Patch #10 works for me

My config : apache reverse proxy with docker

corrected reverse proxying config can fix this issue metioned in #8.

config steps:

1.add X-Forwarded-Proto header in reverse proxy server:

proxy_set_header X-Forwarded-Proto $scheme;

2. config reverse proxy in site settings.php

$settings['reverse_proxy'] = TRUE;
$settings['reverse_proxy_addresses'] = ['172.17.27.0/24']; // reverse_proxy server ip list
$settings['reverse_proxy_trusted_headers'] = \Symfony\Component\HttpFoundation\Request::HEADER_X_FORWARDED_FOR | \Symfony\Component\HttpFoundation\Request::HEADER_X_FORWARDED_HOST | \Symfony\Component\HttpFoundation\Request::HEADER_X_FORWARDED_PORT | \Symfony\Component\HttpFoundation\Request::HEADER_X_FORWARDED_PROTO | \Symfony\Component\HttpFoundation\Request::HEADER_FORWARDED;