[CWEP002] refactor rql read security checking
Split 'check_read_perms' into 'check_relations_perms' which checks relations
'read' permissions and 'get_local_checks' which build dictionary of local
security checks (rql expression) for variables.
This allows to check relations 'read' permissions earlier in the process and so
to prepare insertion of the rql rewriter: we want to check permissions of the
computed relation, not permissions of relations introduced by the associated
rule, to conform to the CWEP.
Related to #3546717
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#
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#
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# any later version.
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# FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
# details.
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"""Simple captcha library, based on PIL. Monkey patch functions in this module
if you want something better...
"""
__docformat__ = "restructuredtext en"
from random import randint, choice
from cStringIO import StringIO
from PIL import Image, ImageFont, ImageDraw, ImageFilter
from time import time
from cubicweb import tags
from cubicweb.web import ProcessFormError, formwidgets as fw
def pil_captcha(text, fontfile, fontsize):
"""Generate a captcha image. Return a PIL image object.
adapted from http://code.activestate.com/recipes/440588/
"""
# randomly select the foreground color
fgcolor = randint(0, 0xffff00)
# make the background color the opposite of fgcolor
bgcolor = fgcolor ^ 0xffffff
# create a font object
font = ImageFont.truetype(fontfile, fontsize)
# determine dimensions of the text
dim = font.getsize(text)
# create a new image slightly larger that the text
img = Image.new('RGB', (dim[0]+5, dim[1]+5), bgcolor)
draw = ImageDraw.Draw(img)
# draw 100 random colored boxes on the background
x, y = img.size
for num in xrange(100):
draw.rectangle((randint(0, x), randint(0, y),
randint(0, x), randint(0, y)),
fill=randint(0, 0xffffff))
# add the text to the image
draw.text((3, 3), text, font=font, fill=fgcolor)
img = img.filter(ImageFilter.EDGE_ENHANCE_MORE)
return img
def captcha(fontfile, fontsize, size=5, format='JPEG'):
"""Generate an arbitrary text, return it together with a buffer containing
the captcha image for the text
"""
text = u''.join(choice('QWERTYUOPASDFGHJKLZXCVBNM') for i in range(size))
img = pil_captcha(text, fontfile, fontsize)
out = StringIO()
img.save(out, format)
out.seek(0)
return text, out
class CaptchaWidget(fw.TextInput):
def render(self, form, field, renderer=None):
# t=int(time()*100) to make sure img is not cached
src = form._cw.build_url('view', vid='captcha', t=int(time()*100),
captchakey=field.input_name(form))
img = tags.img(src=src, alt=u'captcha')
img = u'<div class="captcha">%s</div>' % img
return img + super(CaptchaWidget, self).render(form, field, renderer)
def process_field_data(self, form, field):
captcha = form._cw.session.data.pop(field.input_name(form), None)
val = super(CaptchaWidget, self).process_field_data(form, field)
if val is None:
return val # required will be checked by field
if captcha is None:
msg = form._cw._('unable to check captcha, please try again')
raise ProcessFormError(msg)
elif val.lower() != captcha.lower():
msg = form._cw._('incorrect captcha value')
raise ProcessFormError(msg)
return val