1 | ## $Id: captcha.py 11954 2014-11-13 16:54:17Z henrik $ |
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2 | ## |
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3 | ## Copyright (C) 2011 Uli Fouquet |
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4 | ## This program is free software; you can redistribute it and/or modify |
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5 | ## it under the terms of the GNU General Public License as published by |
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6 | ## the Free Software Foundation; either version 2 of the License, or |
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7 | ## (at your option) any later version. |
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8 | ## |
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9 | ## This program is distributed in the hope that it will be useful, |
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10 | ## but WITHOUT ANY WARRANTY; without even the implied warranty of |
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11 | ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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12 | ## GNU General Public License for more details. |
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13 | ## |
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14 | ## You should have received a copy of the GNU General Public License |
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15 | ## along with this program; if not, write to the Free Software |
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16 | ## Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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17 | ## |
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18 | """Components to add captcha functionality in views/pages. |
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19 | |
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20 | This is currently a playground, stuff still to be worked out more properly. |
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21 | """ |
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22 | import grok |
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23 | import urllib |
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24 | import urllib2 |
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25 | from random import SystemRandom as random |
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26 | from zope import schema |
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27 | from zope.component import getUtilitiesFor, getUtility, queryUtility |
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28 | from zope.interface import Interface |
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29 | from zope.publisher.interfaces.http import IHTTPRequest |
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30 | from waeup.ikoba.browser.layout import IkobaPage |
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31 | from waeup.ikoba.browser.interfaces import ( |
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32 | ICaptchaRequest, ICaptchaResponse, ICaptcha, ICaptchaConfig, |
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33 | ICaptchaManager) |
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34 | from waeup.ikoba.interfaces import ICompany |
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35 | |
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36 | # |
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37 | # Global captcha manager |
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38 | # |
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39 | class CaptchaManager(grok.GlobalUtility): |
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40 | |
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41 | grok.implements(ICaptchaManager) |
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42 | |
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43 | def getAvailCaptchas(self): |
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44 | """Get all available captchas registered as utils for ICaptcha. |
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45 | |
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46 | The default captcha (as it most probably is a copy of another |
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47 | registered captcha) is left out of the result. |
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48 | |
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49 | Result will be a dict with registration names as keys and the |
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50 | specific captcha instances as values. |
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51 | """ |
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52 | result = getUtilitiesFor(ICaptcha) |
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53 | return dict([(name,inst) for name,inst in result |
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54 | if name != u'']) |
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55 | |
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56 | def getCaptcha(self): |
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57 | """Get captcha chosen to be used. |
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58 | |
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59 | Sites can activate a specific captcha by setting |
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60 | ``site['configuration'].captcha``. The attribute should be a |
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61 | string under which the specific captcha is registered. |
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62 | |
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63 | If this attribute is not set or we are |
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64 | not 'in a site', the default captcha is returned. |
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65 | """ |
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66 | site = grok.getSite() |
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67 | name = '' |
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68 | if site is None: |
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69 | return getUtility(ICaptcha) |
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70 | name = getattr(site.get('configuration', {}), 'captcha', u'') |
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71 | return queryUtility(ICaptcha, name=name, |
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72 | default=getUtility(ICaptcha)) |
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73 | |
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74 | ## |
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75 | ## Trivial default captcha |
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76 | ## |
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77 | class CaptchaResponse(object): |
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78 | grok.implements(ICaptchaResponse) |
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79 | def __init__(self, is_valid, error_code=None): |
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80 | self.is_valid = is_valid |
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81 | self.error_code = error_code |
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82 | return |
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83 | |
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84 | class CaptchaRequest(object): |
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85 | grok.implements(ICaptchaRequest) |
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86 | def __init__(self, solution=None, challenge=None): |
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87 | self.solution = solution |
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88 | self.challenge = challenge |
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89 | return |
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90 | |
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91 | class NullCaptcha(object): |
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92 | """A captcha that does not expect any input. |
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93 | |
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94 | Meant as a placeholder for sites that do not want captchas at all. |
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95 | |
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96 | NullCaptchas do not render any HTML/JavaScript and accept any |
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97 | request when asked for verification. |
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98 | |
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99 | They can be used in pages prepared for captchas where the site |
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100 | maintainer decides not to use it at all. |
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101 | """ |
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102 | grok.implements(ICaptcha) |
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103 | |
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104 | def verify(self, request): |
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105 | return CaptchaResponse(True, None) |
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106 | |
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107 | def display(self, error_code=None): |
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108 | return u'' |
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109 | |
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110 | |
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111 | # This captcha is registered twice: one time as a 'no captcha' captcha |
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112 | # and then also as the default captcha (with empty name) |
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113 | grok.global_utility(NullCaptcha, name=u'No captcha') |
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114 | grok.global_utility(NullCaptcha, name=u'') |
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115 | |
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116 | ## |
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117 | ## TestCaptcha |
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118 | ## |
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119 | class StaticCaptcha(object): |
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120 | """The StaticCaptcha always has the same solution: 'the-solution'. |
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121 | |
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122 | It is of no use for real world but for tests. In tests we cannot |
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123 | easily solve really strong captchas. But we can use a captcha that |
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124 | works like a real one but is easy to solve even for machines. |
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125 | |
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126 | The HTML form piece generated is even prefilled with the correct |
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127 | solution. So in tests it is not necessary to always 'type' the |
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128 | solution string in the correct field. |
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129 | |
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130 | You can, however, fill in a wrong solution and it will be detected |
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131 | as such. |
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132 | """ |
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133 | grok.implements(ICaptcha) |
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134 | |
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135 | #: name of solution field in HTTP request |
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136 | sol_field = 'solution' |
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137 | #: name of challenge field in HTTP request |
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138 | chal_field = 'challenge' |
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139 | |
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140 | def verify(self, request): |
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141 | """Verify that a solution sent equals the challenge. |
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142 | """ |
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143 | form = getattr(request, 'form', {}) |
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144 | solution=form.get(self.sol_field, None) |
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145 | challenge=form.get(self.chal_field, None) |
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146 | if solution == challenge and solution: |
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147 | return CaptchaResponse(is_valid=True) |
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148 | return CaptchaResponse(is_valid=False) |
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149 | |
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150 | def display(self, error_code=None): |
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151 | """Display challenge and input field for solution as HTML. |
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152 | """ |
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153 | html = ( |
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154 | u'<input type="hidden" name="challenge"' |
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155 | u' value="the-solution" /><br />' |
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156 | u'Type: %s<br />' |
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157 | u'<input type="text" name="solution" value="the-solution"' |
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158 | u' /><br />') |
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159 | return html |
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160 | |
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161 | grok.global_utility(StaticCaptcha, name=u'Testing captcha') |
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162 | |
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163 | |
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164 | ## |
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165 | ## ReCaptcha |
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166 | ## |
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167 | API_SSL_SERVER = "https://www.google.com/recaptcha/api" |
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168 | VERIFY_SERVER = "https://www.google.com/recaptcha/api" |
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169 | |
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170 | class ReCaptcha(StaticCaptcha): |
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171 | """ReCaptcha - strong captchas with images, sound, etc. |
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172 | |
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173 | This is the Ikoba implementation to support captchas as provided by |
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174 | http://www.google.com/recaptcha. |
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175 | |
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176 | ReCaptcha is widely used and adopted in web applications. See the |
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177 | above web page to learn more about recaptcha. |
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178 | |
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179 | Basically, it generates a captcha box in a page loaded by a |
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180 | client. The client can then enter a solution for a challenge |
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181 | picture (or audio file) and send the solution back to our server |
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182 | along with the challenge string generated locally on the client. |
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183 | |
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184 | This component then verifies the entered solution deploying the |
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185 | private key set by asking a verification server. The result (valid |
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186 | or invalid solution) is then returned to any calling component. |
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187 | |
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188 | As any captcha-component, :class:`ReCaptcha` can be used by any |
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189 | other component that wants to display/verify captchas. |
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190 | |
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191 | To incorporate captcha usage in a view, page, or viewlet, the |
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192 | following steps have to be performed: |
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193 | |
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194 | * get the currently site-wide selected captcha type by doing:: |
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195 | |
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196 | mycaptcha = getUtility(ICaptchaManager).getCaptcha() |
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197 | |
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198 | * if you want a specific captcha type (like ReCaptcha):: |
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199 | |
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200 | mycaptcha = getUtility(ICaptcha, name='ReCaptcha') |
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201 | |
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202 | Now, as you have a captcha, you can verify sent data by doing:: |
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203 | |
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204 | result = mycaptcha.verify(self.request) |
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205 | |
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206 | where ``self.request`` should be the sent HTTP request and |
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207 | ``result`` will be an instance of class:``CaptchaResponse``. The |
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208 | response will contain an error code (``result.error_code``) that |
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209 | might be ``None`` but can (and should) be passed to the |
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210 | :meth:``display`` method to display error messages in the captcha |
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211 | box. The error code is most probably not a human readable string |
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212 | but some code you shouldn't rely upon. |
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213 | |
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214 | All this could be done in the ``update()`` method of a view, page, |
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215 | or viewlet. |
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216 | |
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217 | To render the needed HTML code, you can deploy the |
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218 | :meth:`display`` method of ``mycaptcha``. |
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219 | |
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220 | This captcha is available at runtime as a global utility named |
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221 | ``'ReCaptcha'``. |
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222 | """ |
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223 | |
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224 | grok.implements(ICaptcha) |
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225 | |
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226 | #: name of solution field in HTTP request |
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227 | sol_field = 'recaptcha_response_field' |
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228 | #: name of challenge field in HTTP request |
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229 | chal_field = 'recaptcha_challenge_field' |
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230 | |
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231 | # Do not use the following keys in productive environments! As |
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232 | # they are both made publicly available, they are not secure any |
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233 | # more! Use them for testing and evaluating only! |
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234 | PUBLIC_KEY = "6Lc0y8oSAAAAAHwdojrqPtcKn7Rww5qGprb0rrSk" |
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235 | PRIVATE_KEY = "6Lc0y8oSAAAAAMHVbMrGWLLjw2pm8v2Uprwm9AbR" |
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236 | |
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237 | def verify(self, request): |
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238 | """Grab challenge/solution from HTTP request and verify it. |
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239 | |
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240 | Verification happens against recaptcha remote API servers. It |
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241 | only happens, when really a solution was sent with the |
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242 | request. |
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243 | |
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244 | Returns a :class:`CaptchaResponse` indicating that the |
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245 | verification failed or succeeded. |
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246 | """ |
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247 | form = getattr(request, 'form', {}) |
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248 | solution=form.get(self.sol_field, None) |
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249 | challenge=form.get(self.chal_field, None) |
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250 | if not challenge or not solution: |
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251 | # Might be first-time display of the captcha: not a valid |
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252 | # solution but no error code to prevent any error |
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253 | # messages. Skip further verification. |
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254 | return CaptchaResponse( |
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255 | is_valid=False) |
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256 | params = urllib.urlencode( |
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257 | { |
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258 | 'privatekey': self.PRIVATE_KEY, |
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259 | 'remoteip': '127.0.0.1', |
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260 | 'challenge': challenge, |
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261 | 'response': solution, |
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262 | }) |
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263 | request = urllib2.Request( |
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264 | url = "%s/verify" % VERIFY_SERVER, |
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265 | data = params, |
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266 | headers = { |
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267 | "Content-type": "application/x-www-form-urlencoded", |
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268 | "User-agent": "reCAPTCHA Python Ikoba", |
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269 | } |
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270 | ) |
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271 | resp = urllib2.urlopen(request) |
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272 | ret_vals = resp.read().splitlines() |
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273 | resp.close() |
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274 | ret_code, err_code = ret_vals |
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275 | |
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276 | if ret_code == "true": |
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277 | return CaptchaResponse(is_valid=True) |
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278 | return CaptchaResponse(is_valid=False, error_code=ret_vals[1]) |
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279 | |
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280 | def display(self, error_code=None): |
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281 | """Display challenge and input field for solution as HTML. |
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282 | |
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283 | Returns the HTML code to be placed inside an existing ``<form>`` |
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284 | of your page. You can add other fields and should add a submit |
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285 | button to send the form. |
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286 | |
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287 | The ``error_code`` can be taken from a previously fetched |
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288 | :class:``CaptchaResponse`` instance (as returned by |
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289 | :meth:``verify``). If it is not ``None``, it might be |
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290 | displayed inside the generated captcha box (in human readable |
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291 | form). |
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292 | """ |
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293 | error_param = '' |
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294 | if error_code: |
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295 | error_param = '&error=%s' % error_code |
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296 | |
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297 | html = ( |
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298 | u'<script type="text/javascript" ' |
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299 | u'src="%(ApiServer)s/challenge?k=%(PublicKey)s%(ErrorParam)s">' |
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300 | u'</script>' |
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301 | u'' |
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302 | u'<noscript>' |
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303 | u'<iframe' |
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304 | u' src="%(ApiServer)s/noscript?k=%(PublicKey)s%(ErrorParam)s"' |
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305 | u' height="300" width="500" frameborder="0"></iframe><br />' |
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306 | u'<textarea name="recaptcha_challenge_field"' |
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307 | u' rows="3" cols="40"></textarea>' |
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308 | u'<input type="hidden" name="recaptcha_response_field"' |
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309 | u' value="manual_challenge" />' |
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310 | u'</noscript>' % { |
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311 | 'ApiServer' : API_SSL_SERVER, |
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312 | 'PublicKey' : self.PUBLIC_KEY, |
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313 | 'ErrorParam' : error_param, |
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314 | } |
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315 | ) |
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316 | return html |
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317 | |
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318 | grok.global_utility(ReCaptcha, name=u'ReCaptcha') |
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319 | |
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320 | |
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321 | class CaptchaTestPage(IkobaPage): |
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322 | # A test page to see a captcha in action |
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323 | grok.name('captcha') |
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324 | grok.context(ICompany) |
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325 | grok.require('waeup.Public') |
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326 | title = 'Captcha Test' |
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327 | label = title |
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328 | |
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329 | def update(self, recaptcha_challenge_field=None, |
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330 | recaptcha_response_field=None): |
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331 | self.captcha = getUtility(ICaptcha, name='ReCaptcha') |
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332 | result = self.captcha.verify(self.request) |
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333 | self.captcha_error = result.error_code |
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334 | print "VERIFY: ", result.is_valid, result.error_code |
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335 | return |
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336 | |
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337 | def render(self): |
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338 | return """ |
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339 | <form method="POST" action=""> |
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340 | %s |
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341 | <input type="submit" name="SUBMIT" /> |
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342 | </form> |
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343 | """ % (self.captcha.display(self.captcha_error),) |
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