Pass X-Cors-Headers between the client and the remote

lib/cors-anywhere.js

@@ -210,10 +210,17 @@ function onProxyResponse(proxy, proxyReq, proxyRes, req, res) {
     }
   }
 
+  let extraHeaders = {}
+
   // Strip cookies
-  delete proxyRes.headers['set-cookie'];
-  delete proxyRes.headers['set-cookie2'];
+  for (let k of ['set-cookie', 'set-cookie2']) {
+    if (k in proxyRes.headers) {
+      extraHeaders[k] = proxyRes.headers[k];
+      delete proxyRes.headers[k];
+    }
+  }
 
+  proxyRes.headers['x-cors-headers'] = JSON.stringify(extraHeaders);
   proxyRes.headers['x-final-url'] = requestState.location.href;
   withCORS(proxyRes.headers, req);
   return true;
@@ -392,6 +399,13 @@ function getHandler(options, proxy) {
     var isRequestedOverHttps = req.connection.encrypted || /^\s*https/.test(req.headers['x-forwarded-proto']);
     var proxyBaseUrl = (isRequestedOverHttps ? 'https://' : 'http://') + req.headers.host;
 
+    try {
+        let extraHeaders = JSON.parse(req.headers['x-cors-headers'] || "{}");
+        for (let [k, v] of Object.entries(extraHeaders)) {
+            req.headers[k] = v;
+        }
+    } catch (e) {}
+
     corsAnywhere.removeHeaders.forEach(function(header) {
       delete req.headers[header];
     });