Get the headers of incoming requests using PHP

header_using_apache.php

<?php

$headers = apache_request_headers();

foreach ($headers as $header => $value) {
    echo "$header: $value <br />\n";
}

?>

header_using_server_variables.php

<?php

function getHeaders() {
    $headers = array();
    foreach ($_SERVER as $k => $v) {
        if (substr($k, 0, 5) == "HTTP_") {
            $k = str_replace('_', ' ', substr($k, 5));
            $k = str_replace(' ', '-', ucwords(strtolower($k)));
            $headers[$k] = $v;
        }
    }
    return $headers;
}

?>