How can I return a "CGI Escaped String" in PHP?

How can I return a "CGI Escaped String" in PHP?

the TMDb documentation says that I have to put a CGI escaped string in
order to do a JSON request. I use PHP and i have the following string.
$string = "Movie name";
$search = $tmdb->searchMovie($string);
$string have to be "CGI escaped" to put it in the JSON API request.
Any ideas? Thank you