commit bcf10d76b62568f1b1162016a4e90a03fba5eba3 Author: Isis Lovecruft <isis@torproject.org> Date: Tue Mar 4 08:32:37 2014 +0000 Add HTTPServer.GimpCaptchaProtectedResource class. --- lib/bridgedb/HTTPServer.py | 98 ++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 95 insertions(+), 3 deletions(-) diff --git a/lib/bridgedb/HTTPServer.py b/lib/bridgedb/HTTPServer.py index 5a9d5a3..f525964 100644 --- a/lib/bridgedb/HTTPServer.py +++ b/lib/bridgedb/HTTPServer.py @@ -133,7 +133,7 @@ class CaptchaProtectedResource(twisted.web.resource.Resource): ip = request.getClientIP() return ip - def getCaptchaImage(self): + def getCaptchaImage(self, request=None): """Get a CAPTCHA image. :returns: A 2-tuple of ``(image, challenge)``, where ``image`` is a @@ -183,7 +183,7 @@ class CaptchaProtectedResource(twisted.web.resource.Resource): :returns: A rendered HTML page containing a ReCaptcha challenge image for the client to solve. """ - image, challenge = self.getCaptchaImage() + image, challenge = self.getCaptchaImage(request) try: # TODO: this does not work for versions of IE < 8.0 @@ -225,6 +225,98 @@ class CaptchaProtectedResource(twisted.web.resource.Resource): return redirectTo(request.uri, request) +class GimpCaptchaProtectedResource(CaptchaProtectedResource): + """A web resource which uses a local cache of CAPTCHAs, generated with + gimp-captcha. + + .. _gimp-captcha: https://github.com/isislovecruft/gimp-captcha + """ + + def __init__(self, captchaDir='', + useForwardedHeader=False, resource=None): + CaptchaProtectedResource.__init__(self, useForwardedHeader, resource) + self.captchaDir = captchaDir + + def checkSolution(self, request): + """Process a solved CAPTCHA by sending rehashing the solution together with + the client's IP address, and checking that the result matches the challenge. + + The client's IP address is not sent to the ReCaptcha server; instead, + a completely random IP is generated and sent instead. + + :type request: :api:`twisted.web.http.Request` + + :param request: A ``Request`` object, including POST arguments which + should include two key/value pairs: one key being + ``'captcha_challenge_field'``, and the other, + ``'captcha_response_field'``. These POST arguments should be + obtained from :meth:`render_GET`. + :rtupe: bool + :returns: True, if the CAPTCHA solution was valid; False otherwise. + """ + challenge, response = self.extractClientSolution(request) + clientIP = self.getClientIP(request) + solution = captcha.GimpCaptcha.check(challenge, response, clientIP) + logging.debug("Captcha from %r. Parameters: %r" + % (Util.logSafely(clientIP), request.args)) + return solution + + def getCaptchaImage(self, request): + """Get a random CAPTCHA image from our **captchaDir**. + + Creates a :class:`~bridgedb.captcha.GimpCaptcha`, and calls its + :meth:`~bridgedb.captcha.GimpCaptcha.get` method to return a random + CAPTCHA and challenge string. + + :returns: A 2-tuple of ``(image, challenge)``, where:: + - ``image`` is a string holding a binary, JPEG-encoded image. + - ``challenge`` is a unique string associated with the request. + """ + clientIP = self.getClientIP(request) + c = captcha.GimpCaptcha(self.captchaDir, clientIP) + + try: + c.get() + except captcha.GimpCaptchaError as error: + logging.error(error) + except Exception as error: + logging.error("Unhandled error while retrieving Gimp captcha!") + logging.error(error) + + return (c.image, c.challenge) + + def render_GET(self, request): + """Retrieve a ReCaptcha from the API server and serve it to the client. + + :type request: :api:`twisted.web.http.Request` + :param request: A ``Request`` object for a page which should be + protected by a CAPTCHA. + :rtype: str + :returns: A rendered HTML page containing a ReCaptcha challenge image + for the client to solve. + """ + return CaptchaProtectedResource.render_GET(self, request) + + def render_POST(self, request): + """Process a client's CAPTCHA solution. + + If the client's CAPTCHA solution is valid (according to + :meth:`checkSolution`), process and serve their original + request. Otherwise, redirect them back to a new CAPTCHA page. + + :type request: :api:`twisted.web.http.Request` + :param request: A ``Request`` object, including POST arguments which + should include two key/value pairs: one key being + ``'captcha_challenge_field'``, and the other, + ``'captcha_response_field'``. These POST arguments + should be obtained from :meth:`render_GET`. + :rtype: str + :returns: A rendered HTML page containing a ReCaptcha challenge image + for the client to solve. + """ + return CaptchaProtectedResource.render_POST(self, request) + + class ReCaptchaProtectedResource(CaptchaProtectedResource): """A web resource which uses the reCaptcha_ service. @@ -238,7 +330,7 @@ class ReCaptchaProtectedResource(CaptchaProtectedResource): self.recaptchaPubKey = recaptchaPubKey self.recaptchaRemoteIP = remoteip - def getCaptchaImage(self): + def getCaptchaImage(self, request): """Get a CAPTCHA image from the remote reCaptcha server. :returns: A 2-tuple of ``(image, challenge)``, where::