Source file error.ml

type t = { code : string; message : string; data : Yojson.Safe.t option }

let make ?data code message = { code; message; data }
let unknown_method method_ = make "unknown_method" ("Unknown method: " ^ method_)
let bad_request message = make "bad_request" message
let invalid_json message = make "invalid_json" message
let protocol_error message = make "protocol_error" message
let internal_error message = make "internal_error" message

let to_yojson { code; message; data } =
  let fields = [ ("code", `String code); ("message", `String message) ] in
  let fields =
    match data with
    | None -> fields
    | Some value -> fields @ [ ("data", value) ]
  in
  `Assoc fields

let of_yojson = function
  | `Assoc fields -> (
      let string_field name =
        match List.assoc_opt name fields with
        | Some (`String value) -> Ok value
        | Some _ -> Error (name ^ " must be a string")
        | None -> Error ("missing field: " ^ name)
      in
      match (string_field "code", string_field "message") with
      | Ok code, Ok message ->
          Ok { code; message; data = List.assoc_opt "data" fields }
      | Error message, _ | _, Error message -> Error message)
  | _ -> Error "error must be an object"