How to pass variables between pages using http headers? - php

Question

I'm trying to pass an authorization token between two pages of my application and would like to do so using HTTP headers, however my code is not working as expected.
I've tried retrieving the header using getallheaders() from the second page however the header that I pass it from the first page is not present in the list.
This is the flow of what I'm doing
Placing token into the header array
Executing the POST call
Redirecting to second page using header("Location:")
(on second page) Checking the headers
//placing token into header/////////////////////////////////////////
$token_header['Authorization'] = $accessTokenResult['access_token'];
$header = array();
foreach($token_header as $key => $parsed_urlvalue)
{
$header[] = "$key: $parsed_urlvalue";
}
//sending the request//////////////////////////////////////////////
$ch = curl_init();
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
curl_setopt($ch, CURLOPT_USERAGENT, $userAgent);
curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'POST');
curl_setopt($ch, CURLOPT_URL, "./custom_request.php");
curl_setopt($ch, CURLOPT_HTTPHEADER, $header);
$result = curl_exec($ch);
curl_close($ch);
//redirecting to the second page////////////////////////////////////
header("Location: custom_request.php");
die("Redirected to custom request page");
Other page
$headers_recieved = getallheaders();
echo $headers_recieved['Authorization'];
However I'm getting an invalid index error since 'Authorization' is not present.