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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"