Prerender plain PHP dispatcher file, with X-Prerender-Token

index.php

<?php

$uri = $_SERVER["REQUEST_URI"];
$ua = $_SERVER["HTTP_USER_AGENT"];
$static = "home.html";  // your real webapp HTML file (formerly index.html?)

$prerender = 0;

$regex = "baiduspider|twitterbot|facebookexternalhit|rogerbot|linkedinbot|embedly|quora link preview|showyoubot|outbrain|pinterest|slackbot|vkShare|W3C_Validator";

if (preg_match("/($regex)/i", $ua)) {
    $prerender = 1;
}

if (isset($_REQUEST["_escaped_fragment_"])) {
    $prerender = 1;
}

if (preg_match("/(Prerender)/i", $ua)) {
    $prerender = 0;
}

if ($prerender == 1) {
    $ctx = stream_context_create(array(
    'http' => array(
        'timeout' => 180,
        'header'=>"X-Prerender-Token: <PRERENDER TOKEN>\r\n"  // your Prerender token
        )
    )); 
    echo file_get_contents("http://service.prerender.io/" . $_SERVER["SCRIPT_URI"] . "?" . $_SERVER["QUERY_STRING"], 0, $ctx);
}

else {
    $myfile = fopen($static, "r") or die("Unable to open file!");
    echo fread($myfile,filesize($static));
    fclose($myfile);
}

return;

?>