android - Receive a variable in http header PHP -

i know question not going clear similar questions on here talking sending headers, theres alot of questions similar not answering specifically, sorry if answer extremely obvious,

so ive got apk sends x-api-key in header php conversion of code is..

$url = 'example.something.org/test.php'; $data = "$some_data"; $curl = curl_init();  curl_setopt($curl, curlopt_url, $url); curl_setopt($curl, curlopt_post, true); curl_setopt($curl, curlopt_returntransfer, true); curl_setopt($curl, curlopt_postfields, $data); curl_setopt($curl, curlopt_header, true); curl_setopt($curl, curlopt_httpheader, array("x-api-key"=>"find_meeeeeeee")); 

what want collect x-api-key , store variable can send request test.php similar 1 shown, not option run request directly apk dont want data stored client side, need x-api-key request being sent server, technically apk->my_server->external_server

i have tried using print_r $_post , $_server echoed keys in header() multiple other things cant think of right ive tried , searched google as possible

please link answer if has been answered in advance,

**edit: ** ive tried using js code gives me exact same headers

var req = new xmlhttprequest(); req.open('get', document.location, false); req.send(null); var headers = req.getallresponseheaders().tolowercase(); alert(headers); 

set header as:-

$headers = array(     'content-type: application/json',     "x-api-key"=>"find_meeeeeeee" ); curl_setopt($curl, curlinfo_header_out, true); curl_setopt($curl, curlopt_httpheader, $headers); 

in test.php file write lines:-

foreach (getallheaders() $name => $value) {     echo "$name: $value\n"; } 

hope :)