Cadence Connector

Description

Cadence is Elegia’s content system. It drafts, translates and reviews articles
in a brand’s own voice, starting from what the brand has already published.
This plugin is how those articles reach your site: Cadence sends each finished
piece to WordPress, usually as a draft for you to review, and links its
language versions as WPML translations so nobody has to do it by hand.

WPML has no documented REST endpoint for creating or linking translated posts,
so the language variants of a piece never become each other’s translations
without somebody linking them by hand. This plugin exposes an endpoint that
writes that relationship through WPML’s own wpml_set_element_language_details
action, plus endpoints to publish a piece and to replace one it published.

Callers authenticate with a connector key issued on the settings screen, not as
a WordPress user, and every request carries an Ed25519 signature over its own
bytes: the key says a caller may publish here, the signature says this body is
the one that caller composed. A request that disagrees with the site’s state
is refused rather than reconciled: a duplicate identifier, a language the site
does not run, a post this key did not publish.

Nothing else is added: no post types, no front-end output, no telemetry, and no
network requests of its own. The plugin never calls out; it only answers.

The translation-linking endpoint supports WPML 4.5 or newer. The plugin checks
that WPML’s translation hooks are present, not which WPML version is installed,
so an older WPML is not refused, but it is outside the supported range. Only
WPML’s core plugin is used, not the String Translation or Translation Management
add-ons. Monolingual sites run the same plugin with no WPML; which one a site
is must be declared in the request rather than detected here.

Source, full endpoint reference and the security model:
https://github.com/Elegia-io/cadence-wordpress

Technical details