jaredly · June 4, 2022 03:31 · Jun 4, 2022
diff --git a/cors-proxy.js b/cors-proxy.js
@@ -0,0 +1,45 @@
+/**
+ * Usage:
+ * https://worker-name.myusername.workers.dev/?url=http://google.com
+ */
+
+addEventListener('fetch', event => {
+  event.respondWith(handleRequest(event.request))
+})
+
+/**
+ * Respond to the request
+ * @param {Request} request
+ */
+async function handleRequest(request) {
+  if (request.method === "OPTIONS") {
+    return new Response('ok', {headers: {
+      "access-control-allow-origin": request.headers.get('origin'),
+      "access-control-allow-methods": "GET",
+      "access-control-allow-headers": request.headers.get("access-control-request-headers"),
+    }})
+  }
+
+  const url = new URL(request.url)
+  const requested_url = url.searchParams.get('url')
+  const userAgent = url.searchParams.get('userAgent')
+  const headers = {...request.headers}
+  if (userAgent) {
+    headers["User-Agent"] = userAgent
+  }
+
+  const res = await fetch(requested_url, {
+    headers: headers})
+  const body = await res.arrayBuffer()
+  const resHeaders = {}
+  for (let [k, v] of res.headers.entries()) {
+    resHeaders[k] = v
+  }
+  return new Response(body, {
+    status: res.status,
+    headers: {
+      ...resHeaders,
+      "access-control-allow-origin": request.headers.get('origin'),
+    }
+  })
+}