How to get rid of the POST detials in the json message?

I am receiving a msg contains JSON and I have a problem to parse into JSON details. The msg I receive is :

POST /api/school/2/order HTTP/1.1
User-Agent: Guzzle/4.0 curl/7.21.4 PHP/5.5.7
content-type: application/json
Content-Length: 12

{
 "json msg is here"
}

I want to git rid of the first 4 lines ..

Any suggestions ?