swift / URLエンコード

        let query = "ニュース";
        let encoded = query.stringByAddingPercentEncodingWithAllowedCharacters(NSCharacterSet.URLQueryAllowedCharacterSet())
        let url = "https://ajax.googleapis.com/ajax/services/search/news?v=1.0&hl=ja&rsz=8&q=" + encoded!;

関連情報

google-news-api-ref
https://developers.google.com/web-search/docs/reference?csw=1