Media Downloads: use media_entity_download to serve links to documents

[finnlewis]

Coming from #254

https://www.drupal.org/project/media_entity_download

This module is very popular and is mainained by berdir, so comes with good creds.

This will allow us to set links to files to be like:

/media/123/download

PHP then streams the file, with cache tags.

If we go this way, we'd then want to

• 1. Update the linkit document links to serve the canonical media/123/download link
• 2. Update the media entity embed to provide the link to the canonical media/123/download
• 3. Maybe update other places we link to documents ( although this may be covered by 2.)
• 4. Add permissions for anonymous and authenticated to access dowload media entity links.

[finnlewis]

@Adnan-cds has performance concerns with this.

Serving files via php has the potential increase the server load. We should test this!

How much additional server resources might this add?

Note: there is also a potential work around on drupal.org... coming soon... see https://www.drupal.org/project/media_entity_download/issues/2925406#comment-16034807

[andybroomfield]

To add, some hosts (Acquia) will count 200 requests that bootstrap Drupal against their usage quota, but direct downloads and redirects do not and can be served off the CDN. We would want to ensure we can set that up so that we don't end up with high usage.

[markconroy]

This module looks interesting: https://www.drupal.org/project/media_entity_file_redirect

It was spun out of a comment in the issue linked to by @finnlewis above.

https://www.drupal.org/project/media_entity_download/issues/2925406#comment-12880225