cowboy添加验证码

参考的http://beebole.com/blog/erlang/how-to-implement-captcha-in-erlang-web-application/，移到cowboy，修改了下；废话不多说，直接贴代码

注意，需要cowboy版本1.0.1

需要imagemagick

sudo apt-get install imagemagick

mac

brew install imagemagick

mac下如果使用convert命令找不到字体，则需要安装下这个

brew install ghostscript

创建工程

rebar-creator create-app testCaptcha

testCaptcha_app

-module(testCaptcha_app).

-behaviour(application).

-export([start/, stop/]).

-define(C_ACCEPTORS,  ).

start(_StartType, _StartArgs) ->

    simple_captcha_ets:init(),

    application:start(crypto),

    application:start(cowlib),

    application:start(ranch),

    application:start(cowboy),

    Routes    = route_helper:get_routes(),

    Dispatch  = cowboy_router:compile(Routes),

    Port      = ,

    TransOpts = [{port, Port}],

    ProtoOpts = [{env, [{dispatch, Dispatch}]}],

    cowboy:start_http(http, ?C_ACCEPTORS, TransOpts, ProtoOpts).

stop(_State) ->

    simple_captcha_ets:destroy(),

    ok.


route_helper

-module(route_helper).

-export([get_routes/]).

get_routes() ->

    [

        {'_', [

            {"/captcha", captcha_handler, []},

            {"/captcha_check", captcha_check_handler, []}

        ]}

    ].

simple_captcha

-module(simple_captcha).

-export([create/,check/]).

create() ->

    CryptKey  = mochihex:to_hex(crypto:rand_bytes()),

    Code = generate_rand(),

    FileName = lists:flatmap(fun(Item) -> integer_to_list(Item) end, tuple_to_list(now())),

    File = io_lib:format("/tmp/~s.png",[FileName]),

    Cmd = io_lib:format("convert -background 'none' -fill '#222222' -size 175 -gravity Center -wave 5x100 -swirl 50 -font DejaVu-Serif-Book -pointsize 28 label:~s -draw 'Bezier 10,40 50,35 100,35 150,35 200,50 250,35 300,35' ~s", [Code, File]),

    os:cmd(Cmd),

    {ok, BinPng} = file:read_file(File),

    file:delete(File),

    simple_captcha_ets:insert(Code,CryptKey),

    {erlang:list_to_bitstring(CryptKey),BinPng}.

check(CryptKeyBitString,CodeBitString) ->

    CryptKey = erlang:bitstring_to_list(CryptKeyBitString),

    Code = erlang:bitstring_to_list(CodeBitString),

    CryptKeyFromEts = simple_captcha_ets:find(Code),

    case string:equal(CryptKeyFromEts,CryptKey) of

        true ->

            simple_captcha_ets:remove(code),

            true;

        _ ->

            false

    end.

%private

generate_rand(Length) ->

    Now = now(),

    random:seed(element(, Now), element(, Now), element(, Now)),

    lists:foldl(fun(_I, Acc) -> [do_rand() | Acc] end, [], lists:seq(, Length)).

do_rand(R) when R > , R < ; R > , R < ; R >  ->

    R;

do_rand(_R) ->

    do_rand( + random:uniform()).

simple_captcha_ets

-module(simple_captcha_ets).

-export([init/,insert/,find/,remove/,destroy/]).

init()->

  TableName = ets:new(simple_captcha, [public,named_table]),

  {ok, TableName}.

insert(Key,Value) ->

  ets:insert(simple_captcha, {Key, Value}),

  ok.

find(Key) ->

  Result = (

      try ets:lookup_element(simple_captcha, Key, ) of

        Value ->

          Value

      catch

        _:_ ->

          ""

      end

  ),

  Result.

remove(Key) ->

  try ets:delete(simple_captcha, Key)

  catch

    _:_ ->

      ok

  end.

destroy()->

  try ets:delete(simple_captcha)

  catch

    _:_ ->

      ok

  end.

mochihex

自己下载

captcha_handler

-module(captcha_handler).

-export([init/]).

-export([handle/]).

-export([terminate/]).

init(_Transport, Req, []) ->

  {ok, Req, undefined}.

handle(Req, State) ->

  %CryptKey用于验证的时候用，需本地保存，CapCode为用户提交的数据

  %simple_captcha:check(CryptKey, CapCode)

  {CryptKey,BinPng} =  simple_captcha:create(),

  Req2 = cowboy_req:set_resp_cookie(<<"cap">>, CryptKey, [{path, <<"/">>}], Req),

  {ok, Req3} = cowboy_req:reply(, [{<<"content-type">>, <<"image/png">>}],BinPng, Req2),

  {ok, Req3, State}.

terminate(_Reason, _Req, _State) ->

  ok.

captcha_check_handler

-module(captcha_check_handler).

-export([init/]).

-export([handle/]).

-export([terminate/]).

init(_Transport, Req, []) ->

  {ok, Req, undefined}.

handle(Req, State) ->

  {CryptKey,_} = cowboy_req:cookie(<<"cap">>, Req,<<"">>),

  {ok, PostVals, Req2} = cowboy_req:body_qs(Req),

  CaptchaCode = proplists:get_value(<<"captchaCode">>, PostVals),

  case simple_captcha:check(CryptKey, CaptchaCode) of

    true ->

      {ok, Req3} = cowboy_req:reply(, [{<<"content-type">>, <<"text/html">>}],<<"ok">>, Req2),

      {ok, Req3, State};

    _ ->

      {ok, Req3} = cowboy_req:reply(, [{<<"content-type">>, <<"text/html">>}],<<"error">>, Req2),

      {ok, Req3, State}

  end.

terminate(_Reason, _Req, _State) ->

  ok.

rebar.config

% -*- erlang -*-

{erl_opts, [debug_info]}.

{deps, [

  {cowboy,".*", {git, "https://github.com/ninenines/cowboy", {tag,"1.0.1"}}}

]}.

{cover_enabled, true}.

{eunit_opts, [verbose, {report,{eunit_surefire,[{dir,"."}]}}]}.

{sub_dirs, ["apps/testCaptcha", "rel"]}.

run.sh

#!/bin/sh

rebar clean;

rebar compile;

erl -pa apps/*/ebin deps/*/ebin -eval "application:start(testCaptcha)."

captcha_test.html

<img src="http://127.0.0.1:8080/captcha" width="" height="">

<form action="http://127.0.0.1:8080/captcha_check" method="post">

  <p>captcha<input type="text" name="captchaCode" /></p>

  <input type="submit" value="Submit" />

</form>

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cowboy添加验证码

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