fix [@Prefix]

lib/ppx_deriving_router.ml

@@ -125,10 +125,7 @@ let derive_mount td m =
                 Lwt.return [%e make_with_encode encode])
           in
           Ppx_deriving_router_runtime.prefix_route
-            [%e
-              match m.m_prefix with
-              | Some p -> [%expr Some [%e estring ~loc p]]
-              | None -> [%expr None]]
+            [%e elist ~loc (List.map m.m_prefix ~f:(estring ~loc))]
             f route)
         [%e routes]]
   in

lib/ppx_deriving_router_common.ml

@@ -40,7 +40,7 @@ and path_segment = Ppath of string | Pparam of string * core_type
 type route = Leaf of leaf | Mount of mount
 
 and mount = {
-  m_prefix : string option;
+  m_prefix : string list;
   m_typ : longident loc;
   m_typ_param : label option;
   m_ctor : constructor_declaration;
@@ -221,15 +221,13 @@ let extract td =
         | `mount (m_typ, m_typ_param) ->
             let m_prefix =
               match Attribute.get attr_prefix ctor with
-              | None -> Some ctor.pcd_name.txt
-              | Some path -> (
+              | None -> [ ctor.pcd_name.txt ]
+              | Some path ->
                   let path = path.txt in
-                  let path =
-                    match String.chop_prefix ~pre:"/" path with
-                    | Some path -> path
-                    | None -> path
-                  in
-                  match path with "" -> None | path -> Some path)
+                  let path = String.split_on_char ~by:'/' path in
+                  List.filter_map path ~f:(function
+                    | "" -> None
+                    | x -> Some x)
             in
             let m_response = extract_mount_response ctor.pcd_res in
             Mount
@@ -451,7 +449,9 @@ module Derive_href = struct
           ->
             let prefix =
               estring ~loc
-                (match m_prefix with Some p -> "/" ^ p | None -> "")
+                (match m_prefix with
+                | [] -> ""
+                | p -> "/" ^ String.concat ~sep:"/" p)
             in
             let loc = m_ctor.pcd_loc in
             let p, x = match_ctor m_ctor in

runtime/ppx_deriving_router_runtime.ml

@@ -59,8 +59,13 @@ type 'v route =
 
 let prefix_route prefix f (Route (path, a, g)) =
   match prefix with
-  | None -> Route (path, a, fun x -> f (g x))
-  | Some prefix -> Route (Routes.(s prefix /~ path), a, fun x -> f (g x))
+  | [] -> Route (path, a, fun x -> f (g x))
+  | prefix ->
+      let rec prefix_path p = function
+        | [] -> p
+        | x :: xs -> prefix_path Routes.(s x /~ p) xs
+      in
+      Route (prefix_path path (List.rev prefix), a, fun x -> f (g x))
 
 let to_route (Route (path, a, f)) = Routes.(map f (route path a))
 

runtime/ppx_deriving_router_runtime.mli

@@ -52,7 +52,7 @@ val encode : 'a encode -> 'a -> response Lwt.t
 type 'v route =
   | Route : ('a, 'v) Routes.path * 'a * ('v -> 'w) -> 'w route
 
-val prefix_route : string option -> ('a -> 'b) -> 'a route -> 'b route
+val prefix_route : string list -> ('a -> 'b) -> 'a route -> 'b route
 val to_route : 'a route -> 'a Routes.route
 
 (** ROUTER *)

test/routing.ml

@@ -45,6 +45,6 @@ module All = struct
   type _ t =
     | Pages : Pages.t -> Ppx_deriving_router_runtime.response t
         [@prefix "/"]
-    | Api : 'a Api.t -> 'a t [@prefix "/api"]
+    | Api : 'a Api.t -> 'a t [@prefix "/nested/api"]
   [@@deriving router]
 end

test/test.ml

@@ -87,7 +87,7 @@ let test () =
   print_endline "# TESTING ROUTE MATCHING GENERATION (ALL)";
   test_req all_handler `GET "/hello/world";
   test_req all_handler `GET "/";
-  test_req all_handler `GET "/api/121"
+  test_req all_handler `GET "/nested/api/121"
 
 let () =
   match Sys.argv.(1) with

test/test.t

@@ -8,7 +8,7 @@
   /hello/world?modifier=uppercase
   /121
   /hello/world
-  /api/121
+  /nested/api/121
   # TESTING ROUTE MATCHING GENERATION
   ## GET /
   OK: HOME PAGE
@@ -44,5 +44,5 @@
   OK: Hello, world!
   ## GET /
   OK: HOME PAGE
-  ## GET /api/121
+  ## GET /nested/api/121
   OK: {"id":121}