Using iRules for JSON response

Ok, so the following is the iRule that we have in the LTM now. We are seeing HTTP REQUEST REST DETECTED, but we are not see any REQUEST_BLOCKING messages in the logs. If someone could help in finding why this is not functioning complete, it would be greatly appreciated. We are running on 11.2.0 HF1.

when HTTP_REQUEST { if { [HTTP::uri] contains "rest" } { set rest_content 1 log local0. "HTTP REQUEST REST DETECTED" } else { set rest_content 0 } }

when ASM_REQUEST_BLOCKING { log local0. "ASM REQUEST BLOCK: REST DETECTED= $rest_content" if { $rest_content } {

  ASM::payload replace 0 [ASM::payload length] ""
  ASM::payload replace 0 0 $response

}

}