Use docker-compose

• Fill in the dot.env and rename to .env
• docker-compose up -d
• To shutdown: docker-compose down
• After installed (admin created?), we need to add two more config to make it work behind proxy
  • docker exec --user www-data <nextcloud_app_container_name> php occ config:system:set overwriteprotocol --value="https" --type=string
  • docker exec --user www-data <nextcloud_app_container_name> php occ config:system:set overwritehost --value="https" --type=string
• Nextcloud DB optimization as suggested in the setting overview page
  • docker exec --user www-data <nextcloud_app_container_name> php occ db:convert-filecache-bigint
  • docker exec --user www-data <nextcloud_app_container_name> php occ db:add-missing-indices

YouTube Downloader

The ocDownloader NextCloud app is supposed to be working for HTTP and BT download once it is installed.

However, the YouTube Downloader feature of it may not work properly at the first time. Note that youtube-dl is donwloaded to to /usr/local/bin/youtube-dl in the nextcloud image built from ./nextcloud/Dockerfile.

This problem can be solved by (on NextCloud 18.04):

• go to the Additional Settings page of the admin's setting page
• clear the youtube-dl binary path, the page will say something like "can't find the youtube-dl binary"
• reset the youtube-dl binary path to /usr/local/bin/youtube-dl, the page will say something like "good"

It seems like it is just a bug in the ocDownloader that the default path is working properly, users need to set the path at least once to make it work.

Set Session Lifetime

# Disable keep-alive
docker exec --user www-data <nextcloud_app_container_name> php occ config:system:set \
  session_keepalive --value=false --type=bool

# 10 Minute Lifetime
docker exec --user www-data <nextcloud_app_container_name> php occ config:system:set \
  session_lifetime --value=600 --type=integer

Enable Preview Generation

# Explicitly enable preview
docker exec --user www-data <nextcloud_app_container_name> php occ config:system:set \
  enable_previews --value="true" --type=bool
  
# Explicitly list the providers to use
docker exec --user www-data <nextcloud_app_container_name> php occ config:system:set \
  enabledPreviewProvider <index> --value="OC\Preview\<provider>" --type=string

Indices and Provider

• 0: PNG
• 1: JPEG
• 2: GIF
• 3: HEIC
• 4: BMP
• 5: XBitmap
• 6: MP3
• 7: TXT
• 8: MarkDown
• 9: Movie
• 10: PDF
• 11: MSOfficeDoc
• 12: MSOffice2003
• 13: MSOffice2007
• 14: SVG
• 15: Font

Pre-Generate Preview

It is also important to pre-generate previews for all existing data. Otherwise when using apps like Photos, IO congestion can happen due to large amount of preview generation tasks running at the same time.

1. Install this app: https://apps.nextcloud.com/apps/previewgenerator
2. Run the pre-generate command: docker exec --user www-data <nextcloud_container_name> occ php preview:generate-all -vvv. Note this may run a long time, depends on how many existing files are there.
3. Schdule preview generation timer (below)

The official document. Note the official document is not designed for NextCloud on docker specifically.

Add Scheduled Preview Generation Task:

# login to the shell of nextcloud container
docker exec -it <nextcloud_container_name> bash
# use the 'crontab' in the busybox, with user: www-data
busybox crontab -e -u www-data
# In the opened file, add (assume the scheduled time is 4AM):
0 4 * * * php occ preview:pre-generate