Three ways to get POST data with PHP

Method 1, $_POST

$_POST or $_REQUEST stores the data formatted by PHP in the form of key=>value.

Method 2, use file_get_contents("php://input")

For POST data without specified Content-Type, you can use file_get_contents("php://input"); to obtain the original data.
In fact, any data received by POST using PHP uses this method. Regardless of Content-Type, including binary file streams is also feasible.
Compared with $HTTP_RAW_POST_DATA, it puts less pressure on memory and does not require any special php.ini settings.
php://input cannot read POST data whose Content-Type is multipart/form-data. You need to set the always_populate_raw_post_data value in php.ini to On.
php://input cannot read $_GET data. This is because the $_GET data is written in the PATH field of the http request header as query_path, rather than in the body part of the http request.

Method three, use the global variable $GLOBALS[‘HTTP_RAW_POST_DATA’]

The original data from POST is stored in $GLOBALS[‘HTTP_RAW_POST_DATA’].
But whether the POST data is saved in $GLOBALS['HTTP_RAW_POST_DATA'] depends on the centent-Type setting. Only when PHP cannot recognize the Content-Type, the POST data will be filled in the variable as it is. In $GLOBALS['HTTP_RAW_POST_DATA'], when Content-Type=application/x-www-form-urlencoded, this variable is empty.
In addition, it cannot read POST data whose Content-Type is multipart/form-data. You also need to set the always_populate_raw_post_data value in php.ini to On so that PHP will always fill in the POST data into the variable $http_raw_post_data.