Javascript & CSS not loading after Drupal 8 migration - drupal

Question

I have been given the task of moving two Drupal-based websites to a new server, not because I'm a Drupal expert but I'm the only one in the office with PHP programming skills. One is a Drupal 7 site, the other Drupal 8. These were both given to me as DevDesktop archives and SQL dumps. The Drupal 7 site was pretty straightforward - copied the contents of the docroot up to the new server, created and populated a new MySQL database and edited the default site settings file to point at the new dbase. So the Drupal 7 site works fine. Doing the same with the Drupal 8 site the main problem seems to be it won't load any CSS or Javascript.
In the Javascript Console it threw me off the scent slightly because it said the mime type of the CSS was incorrect, but on further inspection that's because the path to the CSS was returning a 404.
Compounding the problem is Antibot, and as Javascript isn't loading, although I have the username and password for the admin user, I can't login because Antibot keeps sending me back to the homepage telling me to enable Javascript. I have edited settings.php to enable /core/rebuild.php and tried that, but doesn't appear to make any difference. I've also manually truncated the 'cache_...' tables and that doesn't seem to work either. Note that I DON'T have access to SSH on the new server, so can't use drush.
Refused to apply style from '[]' because its MIME type ('text/html') is not a supported stylesheet MIME type, and strict MIME checking is enabled.
Failed to load resource: the server responded with a status of 404 (Not Found)
What it does look like to my non-expert eye is that Drupal is configured somehow to server up optimised versions of the CSS and JS from virtual directories /css/ and /js/, although those paths don't actually exist on the server. I checked the .htaccess file, but other than some clever stuff to deliver gzipped versions to gzip-capable browsers, couldn't see anything in there that would get the server to the correct file. Perhaps if someone could explain how Drupal routes a request to /css/ or /js/ to the right file, that would help my understanding further.
Ultimately I think this problem is because Drupal 8 wants to deliver optimised files, but the cache is screwed and Antibot won't let me get into admin to turn off aggregation.
I have full access to the server files and database, but not drush. Is there a way to turn off the CSS & JS aggregation apart from via the admin menus?

Answer 1

In this situation you can disable aggregation either :
by editing settings.php or settings.local.php :
/**
* Disable CSS and JS aggregation.
*/
$config['system.performance']['css']['preprocess'] = FALSE;
$config['system.performance']['js']['preprocess'] = FALSE;
or via sql, but you have to decode and unserialize blob data from the config table to make the changes, and then make the reverse process :
# Query :
SELECT name, CONVERT (`data` USING utf8) FROM config WHERE `name`='system.performance';
# Unserialize query output and edit data locally
$config = unserialize($output);
$data['css']['preprocess'] = FALSE;
$data['js']['preprocess'] = FALSE;
# Then serialize data and write it back into the config table
# (original encoding is probably `LONGBLOB` but it may differ depending on the backend).
Once you can ssh into the server, you will need to reset permissions and ownership under sites/default/files/ before enabling aggregation again :
mkdir -p sites/default/files/{css,js}
chown -R apache:apache sites/default/files/
chmod -R 0755 sites/default/files/
You may also want to check if the public file path setting (in settings.php) is properly set according to where these ressources are actually located :
$settings['file_public_path'] = 'sites/default/files';