add tangniyuqi/yii2-weixinapi to composer.json
$ composer install$ php composer.phar require tangniyuqi/yii2-weixinapi "*"
or add
"tangniyuqi/yii2-weixinapi": "*"
to the require section of your composer.json file.
in action:
use tangniyuqi\weixinapi\base\Weixin;
new Weixin($config);