Setup Google Font reverse proxy with Apache's `mod_cache` for privacy reasons.
== Systemd service ==
```
name=/etc/systemd/system/apache-htcacheclean-gfont.service
[Unit]
Description=Disk Cache Cleaning Daemon for Apache HTTP Server for the Google Font cache
After=apache2.service
Documentation=https://gitpull.it/T776
[Service]
Type=forking
User=www-data
Environment=HTCACHECLEAN_SIZE=300M
Environment=HTCACHECLEAN_DAEMON_INTERVAL=120
Environment=HTCACHECLEAN_PATH=/var/cache/apache2/mod_cache_disk_gfont
Environment=HTCACHECLEAN_OPTIONS=-n -t
ExecStart=/usr/bin/htcacheclean -d $HTCACHECLEAN_DAEMON_INTERVAL -p $HTCACHECLEAN_PATH -l $HTCACHECLEAN_
[Install]
WantedBy=multi-user.target
```
```
systemctl enable --now apache-htcacheclean-gfont
```
End.
Note: that was inherited from from:
```
systemctl cat apache-htcacheclean.service
```
== Cache directory ==
Create the cache directory like `/var/cache/apache2/mod_cache_disk`:
```
mkdir /var/cache/apache2/mod_cache_disk_gfont
chown www-data: /var/cache/apache2/mod_cache_disk_gfont
```
== VirtualHost ===
TODO