Phoenix: Router: Allow route to match all HTTP verbs

[tisba]

While trying to build a simple HTTP echo server to play around with phoenix, I have to write

get "/echo/*rest", ApiController, :echo
post "/echo/*rest", ApiController, :echo
put "/echo/*rest", ApiController, :echo
patch "/echo/*rest", ApiController, :echo
delete "/echo/*rest", ApiController, :echo
options "/echo/*rest", ApiController, :echo
connect "/echo/*rest", ApiController, :echo
trace "/echo/*rest", ApiController, :echo
head "/echo/*rest", ApiController, :echo

I'd like to have something similar to routes generated by resources:

match "/echo/*rest", ApiController, :echo, :all

This could also allow

match "/echo/*rest", ApiController, :echo, only: [:get, :post]

[Gazler]

:+1: for this.

I think this could be implemented pretty easily by doing something like:

  defmacro match(path, controller, action) do
    do_match path, controller, action, [], do: nil
  end

  #...other macro implementations

  def do_match(path, controller, action, options, do: context) do
  for verb <- @http_methods do
    method = verb |> to_string |> String.upcase
      quote do
        var!(add_route, Phoenix.Router).(
          Scope.route(__MODULE__, unquote(method), unquote(path), unquote(controller),
                                  unquote(action), unquote(options))
        )
      end
    end
  end

[chrismccord]

I think an HTTP echo server is about the only usecase where this comes up, so I don't think it's worth introducing. I would prefer for the users to have their routes listed explicitly, as match can introduce bad behaviors. Like @Gazler said you could write a macro to do this in the cases where it is needed. So I'd rather wait until we have a lot of reports of need first. Thanks!

[Gazler]

@chrismccord Isn't this something that could be useful in the same way that a rails engine is? You mount a plug at a particular endpoint and all request for that path get routed to that plug?

As you said, you could provide a macro in your project to do that.

[chrismccord]

You mount a plug at a particular endpoint and all request for that path get routed to that plug?

Yes, but it wouldn't be via match, it would be with a normal plug.

[chrismccord]

@Gazler I see what you mean now. I would like to have a better story around things like this, but I want to keep it separate from match, which is usually abused. This could be with something like a forward macro or similar. I'd like to explore this area once our 1.0 milestones are taken care of.

[Gazler]

@chrismccord I encountered this issue when toying with the idea of making something like ActiveAdmin.

I had all of my routes handled in: https://github.com/Gazler/ecto_admin/blob/2fc76fb04af482a0350b4d804b5496a1dea5f677/lib/ecto_admin/resource.ex

But the router in a Phoenix application looked like:

defmodule EctoAdminExample.Router do
  use Phoenix.Router

  pipeline :api do
    plug :accepts, ~w(json)
  end

  scope "/", EctoAdminExample do
    pipe_through :api # Use the default browser stack

    get "/", PageController, :index
  end

  get "/admin*args", EctoAdmin.Router, :dispatch
  post "/admin*args", EctoAdmin.Router, :dispatch
end

[tisba]

@chrismccord the echo server is more or less just a playground. My goal is to build a comprehensive test endpoint to test my product (load testing as a service). My idea is that I have a target app (possibly using phoenix) whose behavior can be dynamically configured.

[christopheradams]

I think an HTTP echo server is about the only usecase where this comes up

I have a use case for catch-all path matching that I'd like to mention: creating Webmachine-like Resource plugs to replace Controllers, where the supported HTTP methods are encoded in the Resource module, not the Router.

This is feasible in Plug's Router using the match macro, but in Phoenix you need to generate a route for each method (at compile time).

You mount a plug at a particular endpoint and all request for that path get routed to that plug?

Yes, but it wouldn't be via match, it would be with a normal plug.

It is a match because we want to match on the path and compile a match_route/4 for it; otherwise the router will crash if there's no function head for that path.

I would prefer for the users to have their routes listed explicitly, as match can introduce bad behaviors.

Can you say more about this? My guess is that there's an underlying fear that developers might accidentally put GET and POST requests on the same code path.

Phoenix Router is nice because it doesn't force us to use Controllers (any Plugs will do); it would be even more flexible if it didn't require a verb as part of the route.

So this match all feature is definitely a wontfix?

[josevalim]

@christopheradams forwarding won't work for your use case?

[christopheradams]

@josevalim Forwarding in Phoenix Router doesn't support dynamic path segments, for one (like we added to Plug). But it is another possible workaround depending.

[josevalim]

@christopheradams good point. So I think we should probably support a way for matching on all verbs but it has to be explicit to misuse.

[chrismccord]

@josevalim I just realized we already support this via a special, private verb that we use for forward. This works today to match on all verbs:

    match :*, "/any", SomeController, :any

Shall we doc and expose this publicly? This issue would be resolved then.

[josevalim]

@chrismccord sounds good to me!

[christopheradams]

Amazing!

[mukulpanchal]

@chrismccord - I didn't find the 'match' option in the doc, only learnt about it after seeing this Issue. Is it kept out of the documentation on purpose?

Thank you for exposing "match", helped me a lot