Handling ParameterBag from External Request

Hi,

How to process the below ParameterBag in the Request,

ParameterBag {#43
  #parameters: array:2 [
    "action" => "hello"
    "request" => "a:2:{s:4:"slug";s:5:"lucky";s:7:"version";s:1:"1";}"
  ]
}

or

POST Data
action  
"hello"
request 
"a:2:{s:4:"slug";s:5:"lucky";s:7:"version";s:1:"1";}"

I tried with

1. request('action') and got 'hello'
2. request('request') am getting again whole ParameterBag, not the serialized string.
3. If I try with $_POST['request'] am getting the serialized string.

Can anyone please suggest me how to solve this issue.