The captcha_challenge signal is emitted during the authentication process if the authorizer requires a CAPTCHA to be completed.
The URI of a CAPTCHA image is given, and the program should display this to the user, and return their response (the text displayed in the image). There is no timeout imposed by the library for the response.
| uri |
the URI of the CAPTCHA image to be used |
|
a newly allocated string containing the text in the CAPTCHA image |