docs: function setAuthCodeOnReq(req, res, next) {
      if (req.query.code) {
          req.code = req.query.code;
          debug('Found auth code %s on query param', req.code);
          return next();
      }
  
      //look for something like {"code": "..."}
      if (req.body.code) {
          req.code = req.body.code;
          debug('Found auth code %s in JSON body', req.code);
          return next();
      }
  
      getRawBody(req, function(err, string) {
          if (err) {
              debug(err);
          }
          if (string.toString().length > 0) {
              req.code = string.toString();
              debug('Found auth code %s in body', req.code);
          }
          next();
      });
  }