Recaptcha Element

The recaptcha element produces a recaptcha element. For more information about recaptchas you may refer to https://developers.google.com/recaptcha/

The element is rendered and evaluated by an external library.

The captcha is processed as follows:

• The user solves the captcha.
• If the solution is wrong the captcha gets refreshed until the user gives up or the solution is correct.
• If the solution is correct the Page:event callback is called.
• The return value of the Page:event callback is evaluated as follows:
  • If the value is 'ok' nothing is done.
  • If the return value is 'error', the captcha gets refreshed.
  • If the return value is {'error', Msg}, the captcha gets refreshed and the Msg is shown as the error message.

Before you can use the the recaptcha element, you have to register at https://www.google.com/recaptcha/admin/create.

After that you have to enter your credentials and link information into /rel/nitrogen/etc/app.config as follows:

[
 {nitrogen, [
             {recaptcha, 
              [{public_key, "recaptcha_public_key"},
               {private_key, "recaptcha_private_key"},
               {challenge_url, "http://www.google.com/recaptcha/api/challenge"},
               {verify_url, "http://www.google.com/recaptcha/api/verify"}]}
               ...
 ]},
 ...
].

#recaptcha { }

All attributes are optional

btn_id - (atom)

The button's id

btn_label - (string)

The button's label

captcha_opts - (proplist)

The captcha's options. For more information visit https://developers.google.com/recaptcha/docs/customization

custom_theme_widget is not supported

delegate (Module)

The module where the event callback gets called

fail_body (List)

The fail message. It can be a simple string or an array of element_* items

Code in a page module may looks like this:

inner_body() -> 
    [
        #recaptcha{id=re_captcha, captcha_opts=[{theme,white}]},
    ].

event({recaptcha, ok}) ->
    case check_user_input() of
        ok     -> wf:remove(re_captcha),
                  ok;
        error  -> {error, "FAIL!"}
    end.

user_input() ->
%% your check routine
.