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我正在尝试学习 ChicagoBoss MVC Web 框架，本教程似乎是一个好的开始

https://github.com/ChicagoBoss/ChicagoBoss/wiki/an-evening-with-chicago-boss

直到作者介绍了before_确保required_login调用该功能的功能，这一切都很棒且令人兴奋。我面临的问题是list函数停止被调用，这是我的代码

-module(outings_outgoer_controller, [Req]).
-compile(export_all).
% -export([list/3]).

before_ (Action) ->
    io:fwrite("in before_ Action is: ~s~n", [Action]),
    case Action of
        "login" ->
            ok;
        "register" ->
            ok;
        _ ->
            io:fwrite("  - login is required for this action!~n", []), %gets printed successfully 
            Outgoer = user_lib:require_login(Req),
            io:fwrite("  - ~p is logged in~n", [Outgoer]), %gets printed successfully 
            Outgoer
    end.

list('GET', [], Outgoer) ->
    io:fwrite("An outgoer is requesting his list~n", []), % never gets printed
    {ok, [{outgoer, Outgoer}]}

这是require_login功能

require_login(Req) ->
    case Req:cookie("user_id") of
        undefined -> {redirect, "/outgoer/login"};
        Id ->
            case boss_db:find(Id) of
                undefined -> {redirect, "/outgoer/login"};
                Outgoer ->
                    case Outgoer:session_identifier() =:= Req:cookie("session_id") of
                        false -> {redirect, "/outgoer/login"};
                        true -> {ok, Outgoer}
                    end
            end
     end.

这是我在访问时在控制台中得到的打印outgoer/list

in before_ Action is: list
  - login is required for this action!
  - {ok,{outgoer,"outgoer-1","mohamed","1@3.com",
             "a982ff46c5664edc593329ab558445fc"}} is logged in
20:29:31.439 [notice] [ChicagoBoss] The function outings_outgoer_controller:list/2 is not exported, if in doubt add -export([list/2])) to the module
20:29:31.440 [info] GET /outgoer/list [outings] 200 18ms
Reloading outings_outgoer_controller ... fail: nofile.

我从https://github.com/ChicagoBoss/ChicagoBoss下载了 ChicagoBoss ，我正在使用Erlang 18

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1 回答 1

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It turns out that I got the notice outings_outgoer_controller:list/2 is not exported because the `list' function failed to compile because I forgot to end the function with a dot. anyway I got that hint from http://learnyousomeerlang.com/errors-and-exceptions it says

./module.erl:2: function some_function/1 undefined The function does not exist.
You've written the wrong name or arity either in the -export attribute or when declaring the function. This error is also output when the given function could not be compiled, usually because of a syntax error like forgetting to end a function with a period.

于 2016-07-30T22:55:31.577 回答