Two similar API calls PHP optimisation and structure
I'd start firstly by moving your urlencode() into the class... You should assume that everything passed to a method is unclean and therefore act appropriately.

Secondly, I'd give the class a meaningful name - Process isn't entirely descriptive.

Throw some comments in - follow a set standard such as the PHPDoc format, using @param, @return etc. Always handy to have, even if the code doesn't become public or used by others.

Look at your public/private declarations - or lack of. Personally, I'd look to make your $search and $info URLs private, as well as your returnJson() method.

I'd possibly look to use cURL instead of file_get_contents() - due to some server configs disabling that etc. 

Anyway, just a few suggestions!