<?php

function getLoginHeader(){

    $fields_string = "";
    $username = "youraltemail";
    $password = "youraltpassword";

    $fields = array(
        'username' => urlencode($username),
        'password' => urlencode($password),
        'mod' => urlencode("www"),
        'ssl' => urlencode("0"),
        'dest' => urlencode("community")
    );

    foreach($fields as $key=>$value) { $fields_string .= $key.'='.$value.'&'; }
    $fields_string = substr($fields_string, 0, -1);

    $url = "https://secure.runescape.com/m=weblogin/login.ws";
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_HEADER, true);
    curl_setopt($ch, CURLOPT_POST, 1);
    curl_setopt($ch, CURLOPT_POSTFIELDS, $fields_string);
    curl_setopt($ch, CURLOPT_REFERER, "https://secure.runescape.com/m=weblogin/login.ws");
    curl_setopt($ch, CURLOPT_HTTPHEADER, array(
        "Host: secure.runescape.com",
        "Content-Type: application/x-www-form-urlencoded",
        "Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
        "Acept-Encoding: gzip, deflate, br",
        "Accept-Language: en-US,en;q=0.5",
        "User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:49.0) Gecko/20100101 Firefox/49.0",
    ));
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    $ret = curl_exec($ch);
    curl_close($ch);
    return $ret;
}

$response_headers = getLoginHeader();
$session_index = strpos($response_headers, 'session=');
$session_token = substr($response_headers, $session_index+8, 118);
file_put_contents('/var/www/html/assets/ajax/jagex_session_token.txt', $session_token);

?>