Angular 2 Universal 404 Not Found redirection

Question

I'm implementing a route guard (CanActivate interface) and I need to redirect to not found page under certain conditions. This can be achieved with the following sentence:

if (isNode){
let res : Response = Zone.current.get('res');
res.status(404).redirect('/not-found');
}else{
this.router.navigate(['not-found']);
}

This works, but raises an exception server side (Error: Can't set headers after they are sent), because angular2-universal still sends the rendered page, regardless of the redirection.

Is there any way to solve this properly?

Thanks in advance.

Answer 1

There is actually a solution for bypassing the error.

In server.ts in the res.render method add callback function and check for res.headersSent boolean.

server.get('*', (req, res) => {
  res.render('../public/index.html', {req, res},
    (error, html) => {
      if(error)
        // error handle
      if (!res.headersSent) {
        res.send(html);
      }
    });
});

Obviously, send the html only if res.headersSent is false.