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−# copyright 2003-2010 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
+
−# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
+
−#
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−# This file is part of CubicWeb.
+
−#
+
−# CubicWeb is free software: you can redistribute it and/or modify it under the
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−# terms of the GNU Lesser General Public License as published by the Free
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−# Software Foundation, either version 2.1 of the License, or (at your option)
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−# any later version.
+
−#
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−# CubicWeb is distributed in the hope that it will be useful, but WITHOUT
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−# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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−# FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
+
−# details.
+
−#
+
−# You should have received a copy of the GNU Lesser General Public License along
+
−# with CubicWeb.  If not, see <http://www.gnu.org/licenses/>.
+
−"""Simple captcha library, based on PIL. Monkey patch functions in this module
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−if you want something better...
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−
+
−"""
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−__docformat__ = "restructuredtext en"
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−
+
−from random import randint, choice
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−from cStringIO import StringIO
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−
+
−import Image, ImageFont, ImageDraw, ImageFilter
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−
+
−
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−from time import time
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−
+
−from cubicweb import tags
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−from cubicweb.web import ProcessFormError, formwidgets as fw
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−
+
−
+
−def pil_captcha(text, fontfile, fontsize):
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−    """Generate a captcha image. Return a PIL image object.
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−
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−    adapted from http://code.activestate.com/recipes/440588/
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−    """
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−    # randomly select the foreground color
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−    fgcolor = randint(0, 0xffff00)
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−    # make the background color the opposite of fgcolor
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−    bgcolor = fgcolor ^ 0xffffff
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−    # create a font object
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−    font = ImageFont.truetype(fontfile, fontsize)
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−    # determine dimensions of the text
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−    dim = font.getsize(text)
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−    # create a new image slightly larger that the text
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−    img = Image.new('RGB', (dim[0]+5, dim[1]+5), bgcolor)
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−    draw = ImageDraw.Draw(img)
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−    # draw 100 random colored boxes on the background
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−    x, y = img.size
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−    for num in xrange(100):
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−        draw.rectangle((randint(0, x), randint(0, y),
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−                        randint(0, x), randint(0, y)),
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−                       fill=randint(0, 0xffffff))
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−    # add the text to the image
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−    draw.text((3, 3), text, font=font, fill=fgcolor)
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−    img = img.filter(ImageFilter.EDGE_ENHANCE_MORE)
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−    return img
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−
+
−
+
−def captcha(fontfile, fontsize, size=5, format='JPEG'):
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−    """Generate an arbitrary text, return it together with a buffer containing
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−    the captcha image for the text
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−    """
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−    text = u''.join(choice('QWERTYUOPASDFGHJKLZXCVBNM') for i in range(size))
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−    img = pil_captcha(text, fontfile, fontsize)
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−    out = StringIO()
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−    img.save(out, format)
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−    out.seek(0)
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−    return text, out
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−
+
−
+
−class CaptchaWidget(fw.TextInput):
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−    def render(self, form, field, renderer=None):
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−        # t=int(time()*100) to make sure img is not cached
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−        src = form._cw.build_url('view', vid='captcha', t=int(time()*100),
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−                                 captchakey=field.input_name(form))
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−        img = tags.img(src=src, alt=u'captcha')
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−        img = u'<div class="captcha">%s</div>' % img
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−        return img + super(CaptchaWidget, self).render(form, field, renderer)
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−
+
−    def process_field_data(self, form, field):
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−        captcha = form._cw.session.data.pop(field.input_name(form), None)
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−        val = super(CaptchaWidget, self).process_field_data(form, field)
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−        if val is None:
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−            return val # required will be checked by field
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−        if captcha is None:
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−            msg = form._cw._('unable to check captcha, please try again')
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−            raise ProcessFormError(msg)
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−        elif val.lower() != captcha.lower():
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−            msg = form._cw._('incorrect captcha value')
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−            raise ProcessFormError(msg)
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−        return val