Ways to read data from HTTP request object in ASP.NET webapi

Hi,

I have been trying with Datatable server side processing. Have written a Webapi POST method. It take SearchRequest object which Jquery datatable would take care of sending those details. However i wanted to send extra information as part of JSON data. 

Please find below URL's :

https://datatables.net/examples/server_side/simple.html

https://levelnis.co.uk/blog/datatables-with-web-api-part-2-post-request

How to read the JSON data which has been sent from client side in ASP.NET webapi.