WP_REST_Posts_Controller::get_available_actions

	protected function get_available_actions( $post, $request ) {

		if ( 'edit' !== $request['context'] ) {
			return array();
		}

		$rels = array();

		$post_type = get_post_type_object( $post->post_type );

		if ( 'attachment' !== $this->post_type && current_user_can( $post_type->cap->publish_posts ) ) {
			$rels[] = 'https://api.w.org/action-publish';
		}

		if ( current_user_can( 'unfiltered_html' ) ) {
			$rels[] = 'https://api.w.org/action-unfiltered-html';
		}

		if ( 'post' === $post_type->name ) {
			if ( current_user_can( $post_type->cap->edit_others_posts ) && current_user_can( $post_type->cap->publish_posts ) ) {
				$rels[] = 'https://api.w.org/action-sticky';
			}
		}

		if ( post_type_supports( $post_type->name, 'author' ) ) {
			if ( current_user_can( $post_type->cap->edit_others_posts ) ) {
				$rels[] = 'https://api.w.org/action-assign-author';
			}
		}

		$taxonomies = wp_list_filter( get_object_taxonomies( $this->post_type, 'objects' ), array( 'show_in_rest' => true ) );

		foreach ( $taxonomies as $tax ) {
			$tax_base   = ! empty( $tax->rest_base ) ? $tax->rest_base : $tax->name;
			$create_cap = is_taxonomy_hierarchical( $tax->name ) ? $tax->cap->edit_terms : $tax->cap->assign_terms;

			if ( current_user_can( $create_cap ) ) {
				$rels[] = 'https://api.w.org/action-create-' . $tax_base;
			}

			if ( current_user_can( $tax->cap->assign_terms ) ) {
				$rels[] = 'https://api.w.org/action-assign-' . $tax_base;
			}
		}

		return $rels;
	}