Controlling flow

expressly allows you to control the flow of a request with middleware.

For example, you could edit the Request object:

router.use((req, res) => {
  if (req.urlObj.pathname == "/") {
    req.urlObj.pathname = "/home";
  }
});

This will not redirect the user; instead, it will affect the route selection logic downstream. In this case, a subsequent router.get("/") will not match the request, but router.get("/home") will.

Stopping a request

If you need to end the response process early (for example, in order to block unauthenticated requests), you can call res.end, or res.send, from middleware.

router.use("/account/", (req, res) => {
  if(!("userId" in req.cookies)){
    res.end("You must be logged in to view this page");
  }
});

You can also end the response process by redirecting to a different route:

router.use("/account/", (req, res) => {
  if(!("userId" in req.cookies)){
    res.redirect("/login");
  }
});