增加验证码

utils/captcha/__init__.py

@@ -0,0 +1,112 @@
+# coding:utf-8
+
+"""
+Copyright 2013 TY<tianyu0915@gmail.com>
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+  http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+"""
+
+import os
+import time
+import random
+import StringIO
+import logging
+
+from django.http import HttpResponse
+from PIL import Image, ImageDraw, ImageFont
+
+
+class Captcha(object):
+
+    def __init__(self, request):
+        """   
+        初始化,设置各种属性
+        """
+        self.django_request = request
+        self.session_key = '_django_captcha_key'
+        self.captcha_expires_time = '_django_captcha_expires_time'
+
+        # 验证码图片尺寸
+        self.img_width = 90
+        self.img_height = 30
+
+    def _get_font_size(self, code):
+        """  
+        将图片高度的80%作为字体大小
+        """
+        s1 = int(self.img_height * 0.8)
+        s2 = int(self.img_width / len(code))
+        return int(min((s1, s2)) + max((s1, s2)) * 0.05)
+
+    def _set_answer(self, answer):
+        """  
+        设置答案和过期时间
+        """
+        self.django_request.session[self.session_key] = str(answer)
+        self.django_request.session[self.captcha_expires_time] = time.time() + 60
+
+    def _make_code(self):
+        """
+        生成随机数或随机字符串
+        """
+        string = random.sample('abcdefghkmnpqrstuvwxyzABCDEFGHGKMNOPQRSTUVWXYZ23456789', 4)
+        self._set_answer("".join(string))
+        return string
+
+    def display(self):
+        """
+        生成验证码图片
+        """
+        background = (random.randrange(200, 255), random.randrange(200, 255), random.randrange(200, 255))
+        code_color = (random.randrange(0, 50), random.randrange(0, 50), random.randrange(0, 50), 255)
+
+        font_path = os.path.join(os.path.normpath(os.path.dirname(__file__)), 'timesbi.ttf')
+
+        image = Image.new('RGB', (self.img_width, self.img_height), background)
+        code = self._make_code()
+        font_size = self._get_font_size(code)
+        draw = ImageDraw.Draw(image)
+
+        # x是第一个字母的x坐标
+        x = random.randrange(int(font_size * 0.3), int(font_size * 0.5))
+
+        for i in code:
+            # 字符y坐标
+            y = random.randrange(1, 7)
+            # 随机字符大小
+            font = ImageFont.truetype(font_path.replace('\\', '/'), font_size + random.randrange(-3, 7))
+            draw.text((x, y), i, font=font, fill=code_color)
+            # 随机化字符之间的距离 字符粘连可以降低识别率
+            x += font_size * random.randrange(6, 8) / 10
+
+        buf = StringIO.StringIO()
+        image.save(buf, 'gif')
+
+        self.django_request.session[self.session_key] = "".join(code)
+        return HttpResponse(buf.getvalue(), 'image/gif')
+
+    def check(self, code):
+        """
+        检查用户输入的验证码是否正确
+        """
+        _code = self.django_request.session.get(self.session_key) or ''
+        if not _code:
+            return False
+        expires_time = self.django_request.session.get(self.captcha_expires_time) or 0
+        # 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
+        del self.django_request.session[self.session_key]
+        del self.django_request.session[self.captcha_expires_time]
+        if _code.lower() == str(code).lower() and time.time() < expires_time:
+            return True
+        else:
+            return False