Routing/TimestampedPathGenerator.php
public function generate($name, array $parameters=array(), $updateTrackerName='global', $referenceType = RouterInterface::ABSOLUTE_PATH, $timestampParameterName=null)
    {
        if (!$timestampParameterName) {
            $timestampParameterName = $this->timestampParameterName;
        }
        $parameters[$timestampParameterName] = $this->updateManager->getLastUpdate($updateTrackerName)->format('U');

        return $this->router->generate($name, $parameters, $referenceType);
    }
public function generate($name, array $parameters=array(), $updateTrackerName='global', $referenceType = RouterInterface::ABSOLUTE_PATH, $timestampParameterName=null)
    {
        if (!$timestampParameterName) {
            $timestampParameterName = $this->timestampParameterName;
        }
        $parameters[$timestampParameterName] = $this->updateManager->getLastUpdate($updateTrackerName)->format('U');

        return $this->router->generate($name, $parameters, $referenceType);
    }
Generates an URL containining a timestamp parameter

@param  string $name                   The name of the route
@param  array  $parameters             The parameters of the route
@param  mixed  $updateTrackerName      The update tracker's name or an array of update trackers
@param  int    $referenceType          The type of reference to be returned
@param  string $timestampParameterName The name of the timestamp parameter
@return string