file_get_contents("php://input") or $HTTP_RAW_POST_DATA, which one is better to get the body of JSON request?

file_get_contents("php://input") or $HTTP_RAW_POST_DATA - which one is better to get the body of JSON request?

And which request type (GET or POST) should I use to send JSON data when using client side XmlHTTPRequest?

My question was inspired from this answer: How to post JSON to PHP with curl

Quote from that answer:

From a protocol perspective file_get_contents("php://input") is actually more correct, since you're not really processing http multipart form data anyway.

Actually php://input allows you to read raw request body.

It is a less memory intensive alternative to $HTTP_RAW_POST_DATA and does not need any special php.ini directives. From Reference

php://input is not available with enctype="multipart/form-data".

php://input is a read-only stream that allows you to read raw data from the request body. In the case of POST requests, it is preferable to use php://input instead of $HTTP_RAW_POST_DATA as it does not depend on special php.ini directives. Moreover, for those cases where $HTTP_RAW_POST_DATA is not populated by default, it is a potentially less memory intensive alternative to activating always_populate_raw_post_data.

Source: http://php.net/manual/en/wrappers.php.php.

file_get_contents(php://input) - gets the raw POST data and you need to use this when you write APIs and need XML/JSON/... input that cannot be decoded to $_POST by PHP some example :

send by post JSON string

<input type="button" value= "click" onclick="fn()">
<script>
 function fn(){


    var js_obj = {plugin: 'jquery-json', version: 2.3};

    var encoded = JSON.stringify( js_obj );

var data= encoded


    $.ajax({
  type: "POST",
  url: '1.php',
  data: data,
  success: function(data){
    console.log(data);
  }

});

    }
</script>

1.php

//print_r($_POST); //empty!!! don't work ... 
var_dump( file_get_contents('php://input'));

For JSON data, it's much easier to POST it as "application/json" content-type. If you use GET, you have to URL-encode the JSON in a parameter and it's kind of messy. Also, there is no size limit when you do POST. GET's size if very limited (4K at most).