无法获取php中的原始请求的响应[重复]

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Hi for this great community. I'm new ones to create api's in php. The problem is I'm not able to get the response when i send the raw request from the postman.Here is my code for raw_request_api.php

<?php
if(isset($_REQUEST['json'])) {
    $jsonobj = $_REQUEST['json'];
    $json = json_decode($jsonobj);
    echo json_encode($json);
}else
    echo "Unable to get the request data";

?>  

I'm getting the response when I use Form data as well as x-www-form-urlencoded.

But I'm not able to get the response from the raw data. Please help me where i'm making the mistake? Also I tried every format for raw data...like text/html, application/json, application/xml, text/xml...nothing works

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