Relevant variables:

$_SERVER["HTTPS"] = on
$_SERVER["HTTP_HOST"] = www.xoax.net
$_SERVER["SERVER_NAME"] = www.xoax.net
$_SERVER["SERVER_PORT"] = 443
dirname($_SERVER["PHP_SELF"]) = /sub_php/ref_core/http_json_post

First request (using file_get_contents('php://input')):

First URL = https://www.xoax.net:443/sub_php/ref_core/http_json_post/PostJsonResponse1.php
The response result #1 was {"name":"XoaX.net","value":2}

{
    "name": "XoaX.net",
    "value": 2
}

Second request (using $_POST):

Second URL = https://www.xoax.net:443/sub_php/ref_core/http_json_post/PostJsonResponse2.php
The response result #2 was {"name":"XoaX.net 2","value":3}

{
    "name": "XoaX.net 2",
    "value": 3
}

Third request (using Curl):

Third URL = https://www.xoax.net:443/sub_php/ref_core/http_json_post/PostJsonResponse1.php
The response result #3 was {"name":"XoaX.net","value":2}

{
    "name": "XoaX.net",
    "value": 2
}

Fourth request (using http_build_query() and $_POST):

Fourth URL = https://www.xoax.net:443/sub_php/ref_core/http_json_post/PostJsonResponse2.php
The response result #4 was {"name":"XoaX.net 2","value":3}

{
    "name": "XoaX.net 2",
    "value": 3
}