Small erlang data validator

validate.erl

-module(validate).
-compile(export_all).


list_to_number(L) ->
    try list_to_float(L)
    catch
        error:badarg -> list_to_integer(L)
    end.


% Functions for checking proplists from wild and convert it

check_string(RawString) ->
    RawString.


check_date(RawDateTime) ->
    DateTime = dh_date:parse(RawDateTime),
    case DateTime of
        {error, _} ->
            false;
        DT ->
            DT
    end.


check_number(RawString) ->
    try list_to_number(RawString)
    catch
        error:badarg -> false
    end.


% AtomsList -> [true, false, ...]
% You cant use it in your code directly - you must to define your own validator
% like fun(Value) -> utils:check_atom(Value, [day, month, week, year]) end.
check_atom(RawString, AtomsList) ->
    try lists:member(erlang:list_to_atom(RawString), AtomsList) of
        false -> false;
        true -> erlang:list_to_atom(RawString)
    catch
        error:badarg -> false
    end.


% We use `check_param` func that return value or `false`.
% then we check for Keys that get `false` from validator
% If there is any Keys with false - we return {error, list of this keys}.
% Else proplist with parsed data
% Result list sorted for pattern matching
check_params(Params, Validators) ->
    Checked = lists:map(fun({Key, Validator}) -> {Key, check_param(Key, Validator, Params)} end, Validators),
    Errors = [Key || {Key, false} <- Checked],
    case Errors of
        [] -> lists:sort(Checked);
        _ -> {error, Errors}
    end.


check_param(Key, Validator, Params) ->
    case proplists:get_value(Key, Params) of
        undefined ->
            false;
        Value ->
            Validator(Value)
    end.