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module Util = struct
let split_path target =
let split_target target =
match target with
| "" | "/" -> []
| _ ->
(match String.split_on_char '/' target with
| "" :: xs -> xs
| xs -> xs)
in
match String.index_opt target '?' with
| None -> split_target target
| Some 0 -> []
| Some i -> split_target (String.sub target 0 i)
end
module PatternTrie = struct
module Key = struct
type t =
| Match : string -> t
| Capture : t
end
module KeyMap = Map.Make (String)
type 'a node =
{ parsers : 'a list
; children : 'a node KeyMap.t
; capture : 'a node option
}
type 'a t = 'a node
let empty = { parsers = []; children = KeyMap.empty; capture = None }
let feed_params t params =
let rec aux t params =
match t, params with
| { parsers = []; _ }, [] -> []
| { parsers = rs; _ }, [] -> rs
| { parsers = rs; _ }, [ "" ] -> rs
| { children; capture; _ }, x :: xs ->
(match KeyMap.find_opt x children with
| None ->
(match capture with
| None -> []
| Some t' -> aux t' xs)
| Some m' -> aux m' xs)
in
aux t params
let add k v t =
let rec aux k t =
match k, t with
| [], ({ parsers = x; _ } as n) -> { n with parsers = v :: x }
| x :: r, ({ children; capture; _ } as n) ->
(match x with
| Key.Match w ->
let t' =
match KeyMap.find_opt w children with
| None -> empty
| Some v -> v
in
let t'' = aux r t' in
{ n with children = KeyMap.add w t'' children }
| Key.Capture ->
let t' =
match capture with
| None -> empty
| Some v -> v
in
let t'' = aux r t' in
{ n with capture = Some t'' })
in
aux k t
end
type 'a conv =
{ to_ : 'a -> string
; from_ : string -> 'a option
; label : string
}
let conv to_ from_ label = { to_; from_; label }
type ('a, 'b) path =
| End : { trailing_slash : bool } -> ('a, 'a) path
| Match : string * ('a, 'b) path -> ('a, 'b) path
| Conv : 'c conv * ('a, 'b) path -> ('c -> 'a, 'b) path
type 'b route = Route : ('a, 'b) path * 'a -> 'b route
type 'b router = 'b route PatternTrie.t
let pattern to_ from_ label r = Conv (conv to_ from_ label, r)
let empty_router = PatternTrie.empty
let ( @--> ) r handler = Route (r, handler)
let s w r = Match (w, r)
let of_conv conv r = Conv (conv, r)
let int r = of_conv (conv string_of_int int_of_string_opt ":int") r
let int64 r = of_conv (conv Int64.to_string Int64.of_string_opt ":int64") r
let int32 r = of_conv (conv Int32.to_string Int32.of_string_opt ":int32") r
let str r = of_conv (conv (fun x -> x) (fun x -> Some x) ":string") r
let bool r = of_conv (conv string_of_bool bool_of_string_opt ":bool") r
let ( / ) m1 m2 r = m1 @@ m2 r
let ( /? ) m1 m2 = m1 m2
let nil = End { trailing_slash = false }
let trail = End { trailing_slash = true }
let rec route_pattern : type a b. (a, b) path -> PatternTrie.Key.t list = function
| End _ -> []
| Match (w, fmt) -> PatternTrie.Key.Match w :: route_pattern fmt
| Conv (_, fmt) -> PatternTrie.Key.Capture :: route_pattern fmt
let rec pp_path' : type a b. (a, b) path -> string list = function
| End { trailing_slash } -> if trailing_slash then [ "" ] else []
| Match (w, fmt) -> w :: pp_path' fmt
| Conv ({ label; _ }, fmt) -> label :: pp_path' fmt
let pp_path fmt r = Format.fprintf fmt "%s" ("/" ^ String.concat "/" @@ pp_path' r)
let pp_route fmt (Route (p, _)) = pp_path fmt p
let rec ksprintf' : type a b. (string list -> b) -> (a, b) path -> a =
fun k -> function
| End { trailing_slash } -> if trailing_slash then k [ "" ] else k []
| Match (w, fmt) -> ksprintf' (fun s -> k @@ (w :: s)) fmt
| Conv ({ to_; _ }, fmt) -> fun x -> ksprintf' (fun rest -> k @@ (to_ x :: rest)) fmt
let sprintf r = ksprintf' (fun x -> "/" ^ String.concat "/" x) r
let parse_route fmt handler params =
let rec match_target : type a b. (a, b) path -> a -> string list -> b option =
fun t f s ->
match t with
| End { trailing_slash } ->
(match s with
| [ "" ] when trailing_slash = true -> Some f
| [] when trailing_slash = false -> Some f
| _ -> None)
| Match (x, fmt) ->
(match s with
| x' :: xs when x = x' -> match_target fmt f xs
| _ -> None)
| Conv ({ from_; _ }, fmt) ->
(match s with
| [] -> None
| x :: xs ->
(match from_ x with
| None -> None
| Some x' -> match_target fmt (f x') xs))
in
match_target fmt handler params
let one_of routes =
let routes = List.rev routes in
List.fold_left
(fun routes (Route (r, _) as route) ->
let patterns = route_pattern r in
PatternTrie.add patterns route routes)
empty_router
routes
let add_route route routes =
let (Route (r, _)) = route in
let patterns = route_pattern r in
PatternTrie.add patterns route routes
let run_routes target router =
let routes = PatternTrie.feed_params router target in
let rec aux = function
| [] -> None
| Route (r, h) :: rs ->
(match parse_route r h target with
| None -> aux rs
| Some r -> Some r)
in
aux routes
let match' routes ~target =
let target = Util.split_path target in
let matcher = run_routes target in
matcher routes