Source file `self_serving_client.ml`

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
(*****************************************************************************)
(*                                                                           *)
(* Open Source License                                                       *)
(* Copyright (c) 2020-2021 Nomadic Labs <contact@nomadic-labs.com>           *)
(*                                                                           *)
(* Permission is hereby granted, free of charge, to any person obtaining a   *)
(* copy of this software and associated documentation files (the "Software"),*)
(* to deal in the Software without restriction, including without limitation *)
(* the rights to use, copy, modify, merge, publish, distribute, sublicense,  *)
(* and/or sell copies of the Software, and to permit persons to whom the     *)
(* Software is furnished to do so, subject to the following conditions:      *)
(*                                                                           *)
(* The above copyright notice and this permission notice shall be included   *)
(* in all copies or substantial portions of the Software.                    *)
(*                                                                           *)
(* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR*)
(* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,  *)
(* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL   *)
(* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER*)
(* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING   *)
(* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER       *)
(* DEALINGS IN THE SOFTWARE.                                                 *)
(*                                                                           *)
(*****************************************************************************)

open Lwt.Infix
open Resto_cohttp_server

module Make (Encoding : Resto.ENCODING) (Log : Server.LOGGING) = struct
  module Directory = Resto_directory.Make (Encoding)
  module Media_type = Media_type.Make (Encoding)
  module Server = Server.Make_selfserver (Encoding) (Log)

  type self_server = {
    root : unit Directory.directory;
    cors : Cors.t;
    medias : Server.Media.medias;
    acl : Acl.t;
    agent : string;
  }

  let create (server : self_server) =
    (module struct
      let ( >>=? ) = Lwt_result.( >>= )

      let ( >>? ) v f =
        match v with Error e -> Lwt.return_error e | Ok x -> f x

      let create_stream to_string s =
        Lwt_stream.from (fun () ->
            s.Resto_directory.Answer.next () >|= Option.map to_string)

      let call ~headers ?body meth uri path =
        Directory.lookup server.root () meth path
        >>=? fun (Directory.Service s) ->
        Server.Media.input_media_type server.medias ~headers
        >>? fun input_media_type ->
        Server.Media.output_content_media_type server.medias ~headers
        >>? fun (_output_content_type, output_media_type) ->
        (match
           Resto.Query.parse
             s.types.query
             (List.map (fun (k, l) -> (k, String.concat "," l)) (Uri.query uri))
         with
        | exception Resto.Query.Invalid s ->
            Lwt.return_error (`Cannot_parse_query s)
        | query -> (
            if not @@ Acl.allowed server.acl ~meth ~path then
              Lwt.return_ok (`Unauthorized None)
            else
              match s.types.input with
              | Directory.Service.No_input ->
                  s.handler query () >>= Lwt.return_ok
              | Directory.Service.Input input -> (
                  Cohttp_lwt.Body.to_string
                    (Option.value body ~default:Cohttp_lwt.Body.empty)
                  >>= fun body ->
                  match input_media_type.destruct input body with
                  | Error s -> Lwt.return_error (`Cannot_parse_body s)
                  | Ok body -> s.handler query body >>= Lwt.return_ok)))
        >>= function
        | Ok answer -> (
            let output = output_media_type.construct s.types.output in
            let error = function
              | None -> (Cohttp_lwt.Body.empty, Cohttp.Transfer.Fixed 0L)
              | Some e ->
                  let s = output_media_type.construct s.types.error e in
                  ( Cohttp_lwt.Body.of_string s,
                    Cohttp.Transfer.Fixed (Int64.of_int (String.length s)) )
            in
            match answer with
            | (`Ok _ | `No_content | `Created _) as a ->
                Lwt.return_ok
                @@ Server.Handlers.handle_rpc_answer "local" ~headers output a
            | `OkChunk v ->
                (* When in self-serving mode, there is no point in
                   constructing a sequence just to mash it all together, we
                   ignore Chunk *)
                Lwt.return_ok
                @@ Server.Handlers.handle_rpc_answer
                     "local"
                     ~headers
                     output
                     (`Ok v)
            | `OkStream o ->
                let body = create_stream output o in
                let encoding = Cohttp.Transfer.Chunked in
                Lwt.return_ok
                  ( Cohttp.Response.make ~status:`OK ~encoding ~headers (),
                    Cohttp_lwt.Body.of_stream body )
            | ( `Unauthorized _ | `Forbidden _ | `Gone _ | `Not_found _
              | `Conflict _ | `Error _ ) as a ->
                Lwt.return_ok
                @@ Server.Handlers.handle_rpc_answer_error
                     "local"
                     ~headers
                     error
                     a)
        | Error err ->
            Lwt.return_ok
            @@ Server.Handlers.handle_error
                 (Cohttp.Header.init ())
                 server.medias
                 err

      let call ?headers ?body (meth : Cohttp.Code.meth) uri =
        let path = uri |> Uri.path |> Resto.Utils.decode_split_path in
        let headers = Option.value headers ~default:(Cohttp.Header.init ()) in
        (match meth with
        | #Resto.meth when Server.Handlers.invalid_cors server.cors headers ->
            Lwt.return_ok (Server.Handlers.invalid_cors_response server.agent)
        | #Resto.meth as meth -> call ~headers ?body meth uri path
        | `OPTIONS ->
            Server.Handlers.handle_options server.root server.cors headers path
        | _ -> Lwt.return_error `Not_implemented)
        >>= function
        | Ok a -> Lwt.return a
        | Error err ->
            Lwt.return
            @@ Server.Handlers.handle_error
                 (Cohttp.Header.init ())
                 server.medias
                 err
    end : Client.CALL)

  let launch ?(cors = Cors.default) ?(agent = Server.Agent.default_agent)
      ?(acl = Acl.Allow_all {except = []}) ~media_types root =
    let default_media_type = Server.Media.default_media_type media_types in
    let medias : Server.Media.medias = {media_types; default_media_type} in
    create {root; cors; medias; agent; acl}
end