Python reCAPTCHA v2

captcha.py

# Modified version of https://pypi.python.org/pypi/recaptcha-client
# made to work with recaptcha api v2, since v1 is phasing out soon
# Authors: Ben Maurer <support@recaptcha.net>
#          Maxim Biro <nurupo.contributions@gmail.com>
# License: MIT/X11

import urllib2, urllib, json

class RecaptchaResponse(object):
    def __init__(self, is_valid, error_codes=None):
        self.is_valid = is_valid
        self.error_codes = error_codes

def displayhtml (site_key):
    """Gets the HTML to display for reCAPTCHA

    site_key -- The site api key"""

    return """
<script src='https://www.google.com/recaptcha/api.js'></script>
<div class="g-recaptcha" data-sitekey="%(SiteKey)s"></div>
""" % {
        'SiteKey' : site_key
        }

def submit (recaptcha_response_field,
            secret_key,
            remoteip):
    """
    Submits a reCAPTCHA request for verification. Returns RecaptchaResponse
    for the request

    recaptcha_response_field -- The value of g-recaptcha-response from the form
    secret_key -- your reCAPTCHA secret key
    remoteip -- the user's ip address
    """

    if not (recaptcha_response_field and len (recaptcha_response_field)):
        return RecaptchaResponse (is_valid = False, error_codes = ['incorrect-captcha-sol'])

    def encode_if_necessary(s):
        if isinstance(s, unicode):
            return s.encode('utf-8')
        return s

    params = urllib.urlencode ({
            'secret':    encode_if_necessary(secret_key),
            'remoteip':  encode_if_necessary(remoteip),
            'response':  encode_if_necessary(recaptcha_response_field)
            })

    request = urllib2.Request (
        url = "https://www.google.com/recaptcha/api/siteverify",
        data = params,
        headers = {
            "Content-type": "application/x-www-form-urlencoded",
            "User-agent": "reCAPTCHA Python"
            }
        )

    httpresp = urllib2.urlopen (request)

    data = json.load(httpresp)
    httpresp.close();

    if (data['success']):
        return RecaptchaResponse (is_valid=True)
    else:
        return RecaptchaResponse (is_valid=False, error_codes = data['error-codes'])