From e0e92867d94bb02f1247c559c15580f0312d32d8 Mon Sep 17 00:00:00 2001
From: Thibaut Mattio <thibaut.mattio@gmail.com>
Date: Mon, 1 Jun 2020 16:55:07 +0200
Subject: [PATCH] Add a scope function in Router

---
 opium_kernel/middlewares/router.ml |  9 +++++++++
 opium_kernel/opium_kernel.mli      | 29 +++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+)

diff --git a/opium_kernel/middlewares/router.ml b/opium_kernel/middlewares/router.ml
index 4ad99af8..0aa5d3fb 100644
--- a/opium_kernel/middlewares/router.ml
+++ b/opium_kernel/middlewares/router.ml
@@ -112,6 +112,15 @@ let splat req =
   Hmap0.find_exn Env.key req.Rock.Request.env |> fun route -> route.Route.splat
 ;;
 
+let scope ~route ~middlewares router routes =
+  ListLabels.iter routes ~f:(fun (meth, subroute, action) ->
+      let action =
+        ListLabels.fold_left middlewares ~init:action ~f:(fun h m ->
+            Rock.Middleware.apply m h)
+      in
+      add router ~action ~meth ~route:(Route.of_string (Filename.concat route subroute)))
+;;
+
 let m endpoints =
   let filter default req =
     let url = req.Rock.Request.target in
diff --git a/opium_kernel/opium_kernel.mli b/opium_kernel/opium_kernel.mli
index d5fd6e5c..c4bfab42 100644
--- a/opium_kernel/opium_kernel.mli
+++ b/opium_kernel/opium_kernel.mli
@@ -171,6 +171,35 @@ module Router : sig
   val add : 'a t -> route:Route.t -> meth:Httpaf.Method.standard -> action:'a -> unit
   val param : Rock.Request.t -> string -> string
   val splat : Rock.Request.t -> string list
+
+  (** [scope] adds scoped routes to the router.
+
+      The scoped routes will be prefixed by [route] and their handlers will be wrapped by
+      [middlewares].
+
+      {4 Example}
+
+      Here's an example that defines a scope that will prefix every routes with "/users"
+      and will wrap the handlers with a middleware defined in [Middleware.require_auth].
+
+      {[
+        let () =
+          Router.scope
+            ~middlewares:[ Middleware.require_auth ]
+            ~route:"/users"
+            router
+            [ `POST, "/register", Handlers.register_user
+            ; `POST, "/login", Handlers.login_user
+            ]
+        ;;
+      ]} *)
+  val scope
+    :  route:string
+    -> middlewares:Rock.Middleware.t list
+    -> Rock.Handler.t t
+    -> (Httpaf.Method.standard * string * Rock.Handler.t) list
+    -> unit
+
   val m : Rock.Handler.t t -> Rock.Middleware.t
 end