Can I route on cookies using Routex?

Hi @niccolox,

First of all thank you for showing interest in Routex.

What you are requesting is imho not in scope of Routex itself. Let me try to explain with an analogy:

Consider this analogy…

You are a real estate entrepreneur wanting to build a few houses. You have some global ideas about what houses (route definitions in route.ex) and how they should look (Routex configuration).

Routex would be the architect which takes your ideas (route definitions) and wishes (Routex config) and designs the blueprints. Routex extension are the tools the architect uses to change the blueprints in an efficient manner.

Once the architect has finalized the blueprints, the blueprints are passed to construction company Phoenix.Router to construct the actual houses (routes) following the blueprints. The blueprints are exactly how Phoenix.Router expects them to be. As if they were made for it!

This is the first part: Routex generates blueprints using route definitions and Routex config for Phoenix.Router to build.

The second part is almost a side-effect: As Routex is the architect, it also knows all specifications of the houses produced and so it can produce a few accessories (helper functions) for the houses being build by Phoenix.Router Contruction and co. A fancy electronic door lock, a perfect matching sunscreen and so on. It’s all additional functionality next to all functionality of Phoenix already build, but it makes life a bit easier.

Given this analogy…
What you are asking is a split in the road that leads to the houses so you can route to different houses upfront (before router logic kicks in [1]) OR a split in the hallway once a house entered leading visitors to different rooms (after the router did it’s job [2]).

[1] Varnish, Nginx, Plug
[2] Inside the controller of (Live)View.

Hope this makes sense,
Let me know.

Using plug_http_cache, you can always refuse a cached version to be served by setting the request cache-control: no-cache header.

The spec states that:

The no-cache request directive indicates that the client prefers a stored response not be used to satisfy the request without successful validation on the origin server.

Luckily, plug_http_cache doesn’t support revalidation* and doesn’t return a cached version in this case, so what you have to do is just to write a Plug before plug_http_cache that

• reads if there is a specific cookie / cookie value (user authenticated for instance)
• set this cache-control: no-cache request header if so

Cheers

* You should have a test for this, since plug_http_cache might support revalidation in the future, although it is not very likely

EDIT: might even be better to set the request header cache-control: max-age=0

Thanks guys

I think I am going to pattern a plug on the Phx.auth.gen code such that the plug checks for cookie and then does redirects etc

I want some solution that is very close to core

havent tested this, and obviously its incomplete, but this is the direction

  Used for routes that require the user has no cookies and is probably a first time visitor.
  """
  defp no_cookies_path(_conn), do: "/static"

  def redirect_if_user_no_cookies(conn, _opts) do
    conn = fetch_cookies(conn, signed: [@remember_me_cookie])
    if conn.cookies[@remember_me_cookie] == nil do
      conn
      |> redirect(to: no_cookies_path(conn))
      |> halt()
    else
      conn
    end
  end