-- Basehandler.pm --
package Basehandler;
use Module::I::Always::Use::1;
  ...
use Module::I::Always::Use::35;

sub handler
  {
  ...  same 50 lines of code that do validation and then a jump table to my real work functions ...
  }

sub setup_environment
  {
  ....
  }

-- MyHandler/ForThisEndpoint.pm --
package MyHandler::ForThisEndpoint;
use Basehandler;

sub work_function_1 {}
  ...
sub work_function_100 {}

-- MyHandler/ForAnotherEndpoint.pm --
package MyHandler::ForAnotherEndpoint;
use Basehandler;

sub work_function_1 {}
  ...
sub work_function_100 {}