const BOT_AGENTS = [

 // Search engines ----------------------------------

 "googlebot",

 "bingbot",

 "yandex",

 "baiduspider",

 "duckduckbot",

 "msnbot",

 "adidxbot",

 "yahoo! slurp",

 "qwantify",

 "petalbot",

 "bytespider",

 "sogou web spider",

 "sogou inst spider",

 "exabot",

 "seznambot",

 "naverbot",

 "yetibot",

 "yandexbot",

 "yandeximages",

 "yandexaccessibilitybot",

 // AI Bots and LLM ---------------------------------

 "perplexity",

 "perplexitybot",

 "oai-searchbot",

 "chatgpt",

 "gptbot",

 "claudebot",

 "cohere-ai",

 "youbot",

 // Social networks and preview --------------------

 "facebookexternalhit",

 "twitterbot",

 "linkedinbot",

 "embedly",

 "quora link preview",

 "showyoubot",

 "outbrain",

 "pinterest/0.",

 "developers.google.com/+/web/snippet",

 "slackbot",

 "vkshare",

 "redditbot",

 "whatsapp",

 "flipboard",

 "tumblr",

 "bitlybot",

 "skypeuripreview",

 "nuzzel",

 "discordbot",

 "slackbot-linkexpanding",

 "flipboardproxy",

 "flipboardrss",

 "snapchat",

 "viber",

 "mattermost",

 "telegrambot",

 // SEO and analytics ---------------------------------

 "chrome-lighthouse",

 "lighthouse",

 "google page speed",

 "siteimprove",

 "serpstatbot",

 "uptimerobot",

 "uptimebot",

 "pingdom",

 "gtmetrix",

 "majestic-12",

 "mj12bot",

 "semrushbot",

 "ahrefsbot",

 "dotbot",

 "screaming frog seo spider",

 "seokicks",

 // Others ------------------------------------------

 "rogerbot",

 "360spider",

 "soso",

 "baiduspider-render",

 "applebot",

 "bitrix link preview",

 "xing-contenttabreceiver",

 "integration-test",

 "google-inspectiontool",

 "amazonbot",

 "adsbot-google",

 "googlebot-image",

 "googlebot-news",

 "googlebot-video",

 "facebot",

 "w3c_validator",

 "w3c-checklink",

 "archive.org_bot",

 "paperlibot",

 "dataprovider.com",

 "grapeshotcrawler",

 "zoominfobot",

 "feedly",

 "feedlybot",

 "newsblur",

 "inoreader",

 "ccbot"

];

const IGNORE_EXTENSIONS = [

 ".js",

 ".css",

 ".xml",

 ".less",

 ".png",

 ".jpg",

 ".jpeg",

 ".gif",

 ".pdf",

 ".doc",

 ".txt",

 ".ico",

 ".rss",

 ".zip",

 ".mp3",

 ".rar",

 ".exe",

 ".wmv",

 ".avi",

 ".ppt",

 ".mpg",

 ".mpeg",

 ".tif",

 ".wav",

 ".mov",

 ".psd",

 ".ai",

 ".xls",

 ".mp4",

 ".m4a",

 ".swf",

 ".dat",

 ".dmg",

 ".iso",

 ".flv",

 ".m4v",

 ".torrent",

 ".woff",

 ".ttf",

 ".svg",

 ".webmanifest",

 ".webp"

];

//Hooks into the request, and changes origin if needed

export default {

 async fetch(request, env) {

 return await handleRequest(request, env).catch(

 (err) => new Response(err.stack, { status: 500 })

 );

 },

};

async function handleRequest(request, env) {

 let botAgent = null;

 const url = new URL(request.url);

 const userAgent = request.headers.get("User-Agent")?.toLowerCase() || "";

 const isPerender = request.headers.get("X-Perender");

 const pathName = url.pathname.toLowerCase();

 const extension = pathName

 .substring(pathName.lastIndexOf(".") || pathName.length)

 ?.toLowerCase();

 // Perender loop protection

 // Non robot user agent

 // Ignore extensions

 if (

 isPerender ||

 !BOT_AGENTS.some((bot) => {

 if (userAgent.includes(bot)) {

 botAgent = bot;

 return true;

 }

 return false;

 }) ||

 (extension.length && IGNORE_EXTENSIONS.includes(extension))

 ) {

 return fetch(request);

 }

 // Build Perender request

 const newURL = `https://api.perender.com/Render?url=${request.url}&botAgent=${encodeURIComponent(botAgent)}`;

 const newHeaders = new Headers(request.headers);

 //Add JWT Bearer token to header

 const jwtToken = env.PERENDER_TOKEN;

 if (jwtToken) {

 newHeaders.set("Authorization", `Bearer ${jwtToken}`);

 }

 return fetch(new Request(newURL, {

 headers: newHeaders,

 redirect: "manual",

 }));

}