WordPressマルチサイトで、body_classに"site-hoge"を出力するクラス。

Ms_Body_Class.php

<?php

class Ms_Body_Class {

  public function __construct() {
		add_filter( "body_class", array( $this, "body_class" ));
	}

	public function get_blog_path() {
		$blog_details = get_blog_details($GLOBALS['blog_id']);
		$blog_path = trim( $blog_details->path, "/" );
		return $blog_path;
	}

	public function body_class( $classes ) {
		$blog_path = $this->get_blog_path();
		if(!$blog_path) {
			$blog_path = "main";
		}
		$classes[] = "site-".$blog_path;
		return $classes;
	}
}

new Ms_Body_Class();
?>