def validate(self, value):
print '\n---- CaptchaEntity.validate:', value, self.value, self.created
return (self.value.strip().lower() == value.strip().lower() and
datetime.datetime.now() - self.created <= datetime.timedelta(minutes=app_conf('captcha-valid-minutes')))
def render(self):
font_file = os.path.join(
app_conf('captcha-font-path'),
random.choice([font_file for font_file in os.listdir(app_conf('captcha-font-path')) if fnmatch.fnmatch(font_file, '*.ttf')]))
font = ImageFont.truetype(font_file, app_conf('captcha-font-size'))
text_color = random.choice([(190, 0, 0, 255), (37, 37, 37, 255), (0, 0, 127, 255)])
size = font.getsize(self.captcha_entity.value)
image = Image.new('RGBA', size, (0, 0, 0, 0))
draw = ImageDraw.Draw(image)
draw.text((0, 0), self.captcha_entity.value, font=font, fill=text_color)
# deform begin
project = lambda orig, dist: orig + random.randint(-1 * dist, dist)
divisions = int(len(self.captcha_entity.value) / 1.5)
distorsion = dict(x=app_conf('captcha-distortion-x'), y=app_conf('captcha-distortion-y'))
# add margins
margin_img_size = (
image.size[0] + (2 * distorsion['x']),
image.size[1] + (2 * distorsion['y']),
)
margins_img = Image.new('RGBA', margin_img_size, (0, 0, 0, 0))
margins_img.paste(image, (distorsion['x'], distorsion['y']))
image = margins_img
# calculate distortion mesh
last_projected_x = last_projected_y = 0
mesh = []
for pos in xrange(divisions + 1):
x0 = image.size[0] / divisions * pos
x1 = image.size[0] / divisions * (pos + 1)
y0 = 0
y1 = image.size[1]
projected_x = project(x1, distorsion['x'])
projected_y = project(y0, distorsion['y'])
mesh.append((
(x0, y0, x1, y1),
(
last_projected_x, last_projected_y,
x0, y1,
x1, y1,
projected_x, projected_y,
),
))
last_projected_x, last_projected_y = projected_x, projected_y
image = image.transform(image.size, Image.MESH, mesh, Image.BICUBIC)
image = image.crop(image.getbbox())
# deform end
stringio = StringIO.StringIO()
image.save(stringio, 'PNG') #, quality=100) # TODO png quality?
return (stringio.getvalue(), 'image/png')
def delete_expired(cls):
stmt = "delete from captcha where current_timestamp - created > INTERVAL '%(valid_min)s min'" % dict(valid_min=app_conf('captcha-valid-minutes'))
Session().connection().execute(stmt)# text(stmt))
mark_changed(Session())