Python Flask实现图形验证码及动态刷新完整指南

主目录/utils/captcha/__init__.py

import random
import string

# Image:一个画布
# ImageDraw:一个画笔
# ImageFont:画笔的字体
from PIL import Image, ImageDraw, ImageFont


# Captcha验证码
class Captcha(object):
  # 生成4位数的验证码
  numbers = 4
  # 验证码图片的宽度和高度
  size = (100, 30)
  # 验证码字体大小
  fontsize = 25
  # 加入干扰线的条数
  line_number = 2

  # 构建一个验证码源文本
  SOURCE = list(string.ascii_letters)
  for index in range(0, 10):
    SOURCE.append(str(index))

  # 用来绘制干扰线
  @classmethod
  def __gene_line(cls, draw, width, height):
    begin = (random.randint(0, width), random.randint(0, height))
    end = (random.randint(0, width), random.randint(0, height))
    draw.line([begin, end], fill=cls.__gene_random_color(), width=2)

  # 用来绘制干扰点
  @classmethod
  def __gene_points(cls, draw, point_chance, width, height):
    # 大小限在【0， 100】中
    chance = min(100, max(0, int(point_chance)))
    for w in range(width):
      for h in range(height):
        tmp = random.randint(0, 100)
        if tmp > 100 - chance:
          draw.point((w, h), fill=cls.__gene_random_color())

  # 生成随机颜色
  @classmethod
  def __gene_random_color(cls, start=0, end=255):
    random.seed()
    return (random.randint(start, end),
        random.randint(start, end),
        random.randint(start, end))

  # 随机选择一个字体
  @classmethod
  def __gene_random_font(cls):
    fonts = [
      "PAPYRUS.TTF",
      "CENTAUR.TTF",
      "Inkfree.ttf",
      "verdana.ttf",
    ]
    font = random.choice(fonts)
    return "utils/captcha/"+font

  # 用来随机生成一个字符串（包括英文和数字）
  @classmethod
  def gene_text(cls, numbers):
    # numbers是生成验证码的位数
    return " ".join(random.sample(cls.SOURCE, numbers))

  # 生成验证码
  @classmethod
  def gene_graph_captcha(cls):
    # 验证码图片的宽高
    width, height = cls.size
    # 创建图片
    image = Image.new("RGBA", (width, height), cls.__gene_random_color(0, 100))
    # 验证码的字体
    font = ImageFont.truetype(cls.__gene_random_font(), cls.fontsize)
    # 创建画笔
    draw = ImageDraw.Draw(image)
    # 生成字符串
    text = cls.gene_text(cls.numbers)
    # 获取字体的尺寸
    font_width, font_height = font.getsize(text)
    # 填充字符串
    draw.text(((width-font_width)/2, (height-font_height)/2),
         text, font=font, fill=cls.__gene_random_color(150, 255))
    # 绘制干扰线
    for x in range(0, cls.line_number):
      cls.__gene_line(draw, width, height)
    # 绘制干扰点
    cls.__gene_points(draw, 10, width, height)
    with open("captcha.png", "wb") as fp:
      image.save(fp)
    return text, image

主目录/common/views.py

@bp.route("/captcha")
def graph_captcha():
  """
  使用定义好的图形验证码类，来制作验证码
  以验证码为键、验证码为值（为了用户的体验，让其忽略大小写）存储在redis缓存中
  通过BytesIO字节流的方式保存和访问图片
  :return: 图片响应
  """
  # 获取验证码
  text, image = Captcha.gene_graph_captcha()
  cpcache.set(text.lower(), text.lower())

  # BytesIO:字节流
  out = BytesIO()
  # 保存图片
  image.save(out, "png")
  # 存储完图片，将文件的指针指向文件头，使下次保存图片能覆盖前面保存的图片，节省空间
  out.seek(0)
  # 访问图片，并将其作为一个响应返回给前台
  resp = make_response(out.read())
  resp.content_type = "image/png"
  return resp

<div class="form-group">
  <div class="input-group">
    <input type="text" class="form-control" name="graph_captcha" placeholder="图形验证码">
    <span class="input-group-addon captcha-addon">
      <img id="captcha-img" class="captcha-img" src="{{ url_for("common.graph_captcha") }}" alt="">
    </span>
  </div>
</div>

这个文件放在公共的目录下就可以了

var cpparam = {
  setParam: function(href, key, value){
    //重新加载整个页面
    var isReplaced = false;
    var urlArray = href.split("?");
    if(urlArray.length > 1){
      var queryArray = urlArray[1].split("&");
      for(var i=0; i < queryArray.length; i++){
        var paramArray = queryArray[i].split("=");
        if(paramArray[0] == key){
          paramArray[1] = value;
          queryArray[i] = paramArray.join("=");
          isReplaced = true;
          break;
        }
      }
      if(!isReplaced){
        var params = {};
        params[key] = value;
        if(urlArray.length > 1){
          href = href + "$" + $.param(params);
        }else{
          href = href + "?" + $.param(params);
        }
      }else{
        var params = queryArray.join("&");
        urlArray[1] = params;
        href = urlArray.join("?");
      }
    }else{
      var param = {};
      param[key] = value;
      if(urlArray.length > 1){
        href = href + "$" + $.param(param);
      }else{
        href = href + "?" + $.param(param);
      }
    }
    return href;
  }
};

$(function(){
  $("#captcha-img").on("click", function(){
    var self = $(this);
    var src = self.attr("src");
    var newsrc = cpparam.setParam(src, "xx", Math.random());
    self.attr("src", newsrc);
  });
});