gistfile1.erl

-module(json_parser).
-export([decode_api/1]).

-record(api,  {
        status,
        message,
        timeout
    }).

-record(api1, {
        status
    }).

-record(api2, {
        status,
        message
    }).

-record(api3, {
        status,
        timeout
    }).

decoder() ->
    jsonx:decoder([
            {api,  record_info(fields, api)},
            {api1, record_info(fields, api1)},
            {api2, record_info(fields, api2)},
            {api3, record_info(fields, api3)}
        ]).

decode_api(Json) ->
    Decoder = decoder(),
    case Decoder(Json) of
        #api{} = Result ->
            Result;
        #api1{status = Status1} ->
            #api{status = Status1, message = <<"">>, timeout = 0};
        #api2{status = Status2, message = Message2} ->
            #api{status = Status2, message = Message2, timeout = 0};
        #api3{status = Status3, timeout = Timeout3} ->
            #api{status = Status3, message = <<"">>, timeout = Timeout3};
        Other ->
            Other
    end.