flask 登录验证码 字母和数字

captcha.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

# refer to `https://bitbucket.org/akorn/wheezy.captcha`

import random
import string
import os.path
from cStringIO import StringIO

from PIL import Image
from PIL import ImageFilter
from PIL.ImageDraw import Draw
from PIL.ImageFont import truetype

class Bezier:
def __init__(self):
self.tsequence = tuple([t / 20.0 for t in range(21)])
self.beziers = {}

def pascal_row(self, n):
""" Returns n-th row of Pascal's triangle
"""
result = [1]
x, numerator = 1, n
for denominator in range(1, n // 2 + 1):
x *= numerator
x /= denominator
result.append(x)
numerator -= 1
if n & 1 == 0:
result.extend(reversed(result[:-1]))
else:
result.extend(reversed(result))
return result

def make_bezier(self, n):
""" Bezier curves:
http://en.wikipedia.org/wiki/B%C3%A9zier_curve#Generalization
"""
try:
return self.beziers[n]
except KeyError:
combinations = self.pascal_row(n - 1)
result = []
for t in self.tsequence:
tpowers = (t ** i for i in range(n))
upowers = ((1 - t) ** i for i in range(n - 1, -1, -1))
coefs = [c * a * b for c, a, b in zip(combinations,
tpowers, upowers)]
result.append(coefs)
self.beziers[n] = result
return result

class Captcha(object):
def __init__(self):
self._bezier = Bezier()
self._dir = os.path.dirname(__file__)
# self._captcha_path = os.path.join(self._dir, '..', 'static', 'captcha')

@staticmethod
def instance():
if not hasattr(Captcha, "_instance"):
Captcha._instance = Captcha()
return Captcha._instance

def initialize(self, width=200, height=75, color=None, text=None, fonts=None):
# self.image = Image.new('RGB', (width, height), (255, 255, 255))
self._text = text if text else random.sample(string.uppercase + string.uppercase + '3456789', 4)
self.fonts = fonts if fonts else \
[os.path.join(self._dir, 'fonts', font) for font in ['Arial.ttf', 'Georgia.ttf', 'actionj.ttf']]
self.width = width
self.height = height
self._color = color if color else self.random_color(0, 200, random.randint(220, 255))

@staticmethod
def random_color(start, end, opacity=None):
red = random.randint(start, end)
green = random.randint(start, end)
blue = random.randint(start, end)
if opacity is None:
return red, green, blue
return red, green, blue, opacity

# draw image

def background(self, image):
Draw(image).rectangle([(0, 0), image.size], fill=self.random_color(238, 255))
return image

@staticmethod
def smooth(image):
return image.filter(ImageFilter.SMOOTH)

def curve(self, image, width=4, number=6, color=None):
dx, height = image.size
dx /= number
path = [(dx * i, random.randint(0, height))
for i in xrange(1, number)]
bcoefs = self._bezier.make_bezier(number - 1)
points = []
for coefs in bcoefs:
points.append(tuple(sum([coef * p for coef, p in zip(coefs, ps)])
for ps in zip(*path)))
Draw(image).line(points, fill=color if color else self._color, width=width)
return image

def noise(self, image, number=50, level=2, color=None):
width, height = image.size
dx = width / 10
width -= dx
dy = height / 10
height -= dy
draw = Draw(image)
for i in xrange(number):
x = int(random.uniform(dx, width))
y = int(random.uniform(dy, height))
draw.line(((x, y), (x + level, y)), fill=color if color else self._color, width=level)
return image

def text(self, image, fonts, font_sizes=None, drawings=None, squeeze_factor=0.75, color=None):
color = color if color else self._color
fonts = tuple([truetype(name, size)
for name in fonts
for size in font_sizes or (65, 70, 75)])
draw = Draw(image)
char_images = []
for c in self._text:
font = random.choice(fonts)
c_width, c_height = draw.textsize(c, font=font)
char_image = Image.new('RGB', (c_width, c_height), (0, 0, 0))
char_draw = Draw(char_image)
char_draw.text((0, 0), c, font=font, fill=color)
char_image = char_image.crop(char_image.getbbox())
for drawing in drawings:
d = getattr(self, drawing)
char_image = d(char_image)
char_images.append(char_image)
width, height = image.size
offset = int((width - sum(int(i.size[0] * squeeze_factor)
for i in char_images[:-1]) -
char_images[-1].size[0]) / 2)
for char_image in char_images:
c_width, c_height = char_image.size
mask = char_image.convert('L').point(lambda i: i * 1.97)
image.paste(char_image,
(offset, int((height - c_height) / 2)),
mask)
offset += int(c_width * squeeze_factor)
return image

# draw text
@staticmethod
def warp(image, dx_factor=0.27, dy_factor=0.21):
width, height = image.size
dx = width * dx_factor
dy = height * dy_factor
x1 = int(random.uniform(-dx, dx))
y1 = int(random.uniform(-dy, dy))
x2 = int(random.uniform(-dx, dx))
y2 = int(random.uniform(-dy, dy))
image2 = Image.new('RGB',
(width + abs(x1) + abs(x2),
height + abs(y1) + abs(y2)))
image2.paste(image, (abs(x1), abs(y1)))
width2, height2 = image2.size
return image2.transform(
(width, height), Image.QUAD,
(x1, y1,
-x1, height2 - y2,
width2 + x2, height2 + y2,
width2 - x2, -y1))

@staticmethod
def offset(image, dx_factor=0.1, dy_factor=0.2):
width, height = image.size
dx = int(random.random() * width * dx_factor)
dy = int(random.random() * height * dy_factor)
image2 = Image.new('RGB', (width + dx, height + dy))
image2.paste(image, (dx, dy))
return image2

@staticmethod
def rotate(image, angle=25):
return image.rotate(
random.uniform(-angle, angle), Image.BILINEAR, expand=1)

def captcha(self, path=None, fmt='JPEG'):
"""Create a captcha.

Args:
path: save path, default None.
fmt: image format, PNG / JPEG.
Returns:
A tuple, (name, text, StringIO.value).
For example:
('fXZJN4AFxHGoU5mIlcsdOypa', 'JGW9', '\x89PNG\r\n\x1a\n\x00\x00\x00\r...')

"""
image = Image.new('RGB', (self.width, self.height), (255, 255, 255))
image = self.background(image)
image = self.text(image, self.fonts, drawings=['warp', 'rotate', 'offset'])
image = self.curve(image)
image = self.noise(image)
image = self.smooth(image)
name = "".join(random.sample(string.lowercase + string.uppercase + '3456789', 24))
text = "".join(self._text)
out = StringIO()
image.save(out, format=fmt)
if path:
image.save(os.path.join(path, name), fmt)
return name, text, out.getvalue()

def generate_captcha(self):
self.initialize()
return self.captcha("")

captcha = Captcha.instance()

if __name__ == '__main__':
print captcha.generate_captcha()

validate_picture.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
from . import auth_code_blueprint as authcode
from utils.captcha.captcha import captcha
from flask import make_response, session
from flask import request

@authcode.route('/validate_picture', methods=['GET', 'POST'])
def validate_picture():
name, text, image_data = captcha.generate_captcha()
text = text.lower()

session[text] = text  #后台使用session保存

response = make_response(image_data)
response.headers['Content-Type'] = 'image/jpg'
return response