code/Debug/Helper/Filter.php
public function getRequestFilters(Mage_Core_Controller_Request_Http $request)
    {
        if (!$this->requestFilterValues) {
            $filters = $this->getFilterParams();
            $this->requestFilterValues = array();

            foreach ($filters as $filter) {
                $param = $request->getParam($filter, null);
                if ($param !== null) {
                    $this->requestFilterValues[$filter] = $param;
                }
            }
        }

        return $this->requestFilterValues;
    }
public function getRequestFilters(Mage_Core_Controller_Request_Http $request)
    {
        if (!$this->requestFilterValues) {
            $filters = $this->getFilterParams();
            $this->requestFilterValues = array();

            foreach ($filters as $filter) {
                $param = $request->getParam($filter, null);
                if ($param !== null) {
                    $this->requestFilterValues[$filter] = $param;
                }
            }
        }

        return $this->requestFilterValues;
    }
Returns an assoc array with filter and if its value from request.
Filters missing from request parameters are ignored.

@param Mage_Core_Controller_Request_Http $request
@return array