Conditional response
Return a response based on the incoming request's URL, HTTP method, User Agent, IP address, ASN or device type.
const BLOCKED_HOSTNAMES = ["nope.mywebsite.com", "bye.website.com"]
async function handleRequest(request) { // Return a new Response based on a URL's hostname const url = new URL(request.url)
if (BLOCKED_HOSTNAMES.includes(url.hostname)) { return new Response("Blocked Host", { status: 403 }) }
// Block paths ending in .doc or .xml based on the URL's file extension const forbiddenExtRegExp = new RegExp(/\.(doc|xml)$/)
if (forbiddenExtRegExp.test(url.pathname)) { return new Response("Blocked Extension", { status: 403 }) }
// On HTTP method if (request.method === "POST") { return new Response("Response for POST") }
// On User Agent const userAgent = request.headers.get("User-Agent") || "" if (userAgent.includes("bot")) { return new Response("Block User Agent containing bot", { status: 403 }) }
// On Client's IP address const clientIP = request.headers.get("CF-Connecting-IP") if (clientIP === "1.2.3.4") { return new Response("Block the IP 1.2.3.4", { status: 403 }) }
// On ASN if (request.cf && request.cf.asn == 64512) { return new Response("Block the ASN 64512 response") }
// On Device Type // Requires Enterprise "CF-Device-Type Header" zone setting or // Page Rule with "Cache By Device Type" setting applied. const device = request.headers.get("CF-Device-Type") if (device === "mobile") { return Response.redirect("https://mobile.example.com") }
console.error( "Getting Client's IP address, device type, and ASN are not supported in playground. Must test on a live worker", ) return fetch(request)}
addEventListener("fetch", event => { event.respondWith(handleRequest(event.request))})