mirror of
https://github.com/QingdaoU/OnlineJudge.git
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101 lines
3.6 KiB
Python
101 lines
3.6 KiB
Python
"""
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Copyright 2013 TY<tianyu0915@gmail.com>
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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"""
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import os
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import time
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import random
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from PIL import Image, ImageDraw, ImageFont
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class Captcha(object):
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def __init__(self, request):
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"""
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初始化,设置各种属性
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"""
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self.django_request = request
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self.session_key = "_django_captcha_key"
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self.captcha_expires_time = "_django_captcha_expires_time"
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# 验证码图片尺寸
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self.img_width = 90
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self.img_height = 30
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def _get_font_size(self, code):
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"""
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将图片高度的80%作为字体大小
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"""
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s1 = int(self.img_height * 0.8)
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s2 = int(self.img_width / len(code))
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return int(min((s1, s2)) + max((s1, s2)) * 0.05)
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def _set_answer(self, answer):
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"""
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设置答案和过期时间
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"""
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self.django_request.session[self.session_key] = str(answer)
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self.django_request.session[self.captcha_expires_time] = time.time() + 60
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def _make_code(self):
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"""
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生成随机数或随机字符串
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"""
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string = random.sample("abcdefghkmnpqrstuvwxyzABCDEFGHGKMNOPQRSTUVWXYZ23456789", 4)
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self._set_answer("".join(string))
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return string
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def get(self):
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"""
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生成验证码图片,返回值为图片的bytes
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"""
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background = (random.randrange(200, 255), random.randrange(200, 255), random.randrange(200, 255))
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code_color = (random.randrange(0, 50), random.randrange(0, 50), random.randrange(0, 50), 255)
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font_path = os.path.join(os.path.normpath(os.path.dirname(__file__)), "timesbi.ttf")
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image = Image.new("RGB", (self.img_width, self.img_height), background)
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code = self._make_code()
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font_size = self._get_font_size(code)
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draw = ImageDraw.Draw(image)
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# x是第一个字母的x坐标
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x = random.randrange(int(font_size * 0.3), int(font_size * 0.5))
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for i in code:
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# 字符y坐标
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y = random.randrange(1, 7)
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# 随机字符大小
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font = ImageFont.truetype(font_path.replace("\\", "/"), font_size + random.randrange(-3, 7))
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draw.text((x, y), i, font=font, fill=code_color)
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# 随机化字符之间的距离 字符粘连可以降低识别率
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x += font_size * random.randrange(6, 8) / 10
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self.django_request.session[self.session_key] = "".join(code)
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return image
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def check(self, code):
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"""
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检查用户输入的验证码是否正确
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"""
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_code = self.django_request.session.get(self.session_key) or ""
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if not _code:
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return False
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expires_time = self.django_request.session.get(self.captcha_expires_time) or 0
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# 注意 如果验证之后不清除之前的验证码的话 可能会造成重复验证的现象
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del self.django_request.session[self.session_key]
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del self.django_request.session[self.captcha_expires_time]
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if _code.lower() == str(code).lower() and time.time() < expires_time:
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return True
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else:
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return False
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