fix: detect secure socket when connection is missing

index.js

@@ -641,6 +641,10 @@ function issecure(req, trustProxy) {
     return true;
   }
 
+  if (req.socket && req.socket.encrypted) {
+    return true;
+  }
+
   // do not trust proxy
   if (trustProxy === false) {
     return false;

test/session.js

@@ -854,6 +854,21 @@ describe('session()', function(){
           });
       });
     });
+
+    describe('when request socket is encrypted', function () {
+      it('should treat request as secure when connection is missing', function (done) {
+        function setup (req) {
+          req.connection = null
+          req.socket = { encrypted: true }
+        }
+
+        request(createServer(setup, { cookie: { secure: true } }))
+          .get('/')
+          .expect(shouldSetCookieWithAttribute('connect.sid', 'Secure'))
+          .expect(200, done)
+      })
+    })
+
     describe('when "sameSite" set to "auto"', function () {
       describe('basic functionality', function () {
         before(function () {