Moochiweb router example

dispatcher.erl

-module (dispatcher).
-export ([dispatch/2, convert_method_to_action/1]).



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]}->
      case length(MatchList) of
        0 ->
          Action = convert_method_to_action(Method),
          Handler:Action(Req, []);
          % posts_handler:get(Req)

        Length when Length > 0 ->
          Args = lists:flatten(MatchList),
          Action = convert_method_to_action(Method),
          Handler:Action(Req, Args)
          % posts_handler:get(Req, 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)).

posts_handler.erl

-module (posts_handler).
-include_lib("erlang_couchdb.hrl").
-include_lib("headers.hrl").
-compile(export_all).

% Get one doc or all docs from DB
get(Req, Doc_id) ->
  case Doc_id of
    [] ->
      {json, {struct, Data}} = erlang_couchdb:invoke_view(?DB_HOST, ?DB_POSTS_DATABASE, ?DB_POSTS_DOCUMENT_CLASS, ?DB_ALL_POSTS_VIEW, [{"include_docs", "false"}]);
    _ ->
      {json, {struct, Data}} = erlang_couchdb:retrieve_document(?DB_HOST, ?DB_POSTS_DATABASE, Doc_id)
  end,
  respond_with_json(Req, Data).

% JSON Responder
respond_with_json(Req, Data) ->
  JSON = mochijson2:encode(Data),
  Req:respond({200, [{"Content-Type", ?JSON_H}], JSON}).
  

router.erl

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

urls() -> [
  {"^posts/?$", posts_handler },
  {"^posts/(.+?)/?$", posts_handler } % url: /posts/:post_id
].

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.