Simple URL dispatcher for Mochiweb

dispatcher.erl

-module(dispatcher).
-export([dispatch/2]).

dispatch(_, []) -> none;
dispatch(Req, [{Regexp, Handler}|T]) ->
    "/" ++ Path = Req:get(path),
    Method = Req:get(method),
    Match = re:run(Path, Regexp, [global, {capture, all_but_first, list}]),
    case Match of
        {match, [MatchList]} ->
            % We found a regexp that matches the current URL path
            case length(MatchList) of
                0 ->
                    % We didn't find any URL parameters
                    Action = convert_method_to_action(Method),
                    Handler:Action(Req);

                Length when Length > 0 ->
                    % We pass URL parameters to the function
                    Args = lists:append([[Method, Req], MatchList]),
                    Action = convert_method_to_action(Method),
                    apply(Handler, Action, Args)
            end;
        _ ->
            dispatch(Req, T)
    end.

convert_method_to_action(Method) ->
    List = atom_to_list(Method),
    Action = string:sub_string(List, 1, length(List)),
    list_to_atom(string:to_lower(Action)).

router.erl

-module(router).
-export([urls/0]).

%% Handler modules have functions corresponding
%% to lowercased HTTP methods (get, post etc)
urls() -> [
    {"^1.0/update$", handler_update},
    {"^1.0/check$", handler_check}
].

yourapp_web.erl

%% Mochiweb loop

loop(Req, DocRoot) ->
    "/" ++ Path = Req:get(path),
    try
        case dispatcher:dispatch(Req, router:urls()) of
            none ->
                % No request handler found
                Req:not_found();
            Response ->
                Response
        end
    catch
        Type:What ->
        %% Error handling
        ...
        
    end.