Media domain support

[cameronterry]

This PR adds support to the domain mapping for "Media domains". When added, these domains will be used to map items which are supported by the Media Library on a given site. This will include:

• Audio (AAC, MP3, etc.)
• Documents (PDF, etc.)
• Images (GIF, JPG, PNG, etc.)
• Video (AVI, MOV, MPEG, etc.)

This will also include support for customisations that are provided through upload_mimes hook (WordPress Developer Reference). A good example of a customisation: websites using the Safe SVG plugin.

Testing check list

• [x] Classic Editor with image, video, and file.
• [x] Image Block
• [x] Gallery Block
• [x] Audio Block
• [x] Video Block
• [x] Media and Text Block
• [x] File Block
• [x] Cover Block

CLI changes

wp --url="sites.my.com/sitefifteen" darkmatter domain add fifteen.mycdn.com --type=media

Convert a secondary domain into a media domain. Useful for when repurposing an old domain for use a CDN for media assets.

wp --url="sites.my.com/siteone" darkmatter domain set www.secondarydomain.com --type=media

Convert a Media domain to a main domain. This is useful in scenarios when a media domain is redundant and to ensure it redirects to the website.

wp --url="sites.my.com/siteone" darkmatter domain set www.secondarydomain.com --type=main --secondary

List all domains - of types, "main" and "media".

wp darkmatter domain list

Changelog

• New Features:
  • Say hello to "Media domains"; a new type of domain to Dark Matter that can be used to serve media assets from a different domain name.
  • Useful for separating infrastructure which is used for static assets from servers powering PHP requests.
  • Or powering images through a dedicated / dynamic service such as Tachyon.
  • Can be hard-set using an array of domains in a constant called, DM_NETWORK_MEDIA.
  • Supports all extensions that are supported by the Media Library. So if you add SVG upload support, "Media domains" will support it too.
  • Updating the existing CLIs to support domain types and management of "Media domains".

Performance Check

Both setups are using Twenty Twenty One with object cache enabled and configured, with both containing 842 posts.

Single site installation

Multisite installation on a site with domain mapping configured.

[cameronterry]

Noting, this has only been tested with the Gallery Block on Block Editor. Other image related blocks - i.e. Audio, Cover, Video, etc. - need to be tested.

Classic Editor and shortcodes need tested as well. And logic is needed for Feature Image / attachment related APIs such as wp_get_attachment_image_src().

[cameronterry]

Self note: should provide an ability to set a network-wide CDN domains, which are enforced on all sites. This should be achievable through detecting a constant - such as: DM_NETWORK_CDN - which is an array of domains.

define( 'DM_NETWORK_CDN', [
    'cdn1.mappeddomain1.test',
    'cdn2.mappeddomain1.test',
    'cdn3.mappeddomain1.test',
] );