十八 Django-验证码

一、验证码的作用

防恶意破解密码：防止，使用程序或机器人恶意去试密码．为了提高用户的体验，用户输入错误以后，才会要求输入验证码．

防论坛灌水：这个是很常见的。有一种程序叫做顶帖机，如果无限制的刷，整个论坛可能到处是拉圾信息，比如，百度贴吧，你只要是新用户或者刚刚关注的贴吧，要是发帖，会马上出现验证码。
有效防止注册：防止使用程序或机器人去无限制注册账号．
防刷票：网上有很多投票类的网站.
反爬：防止爬虫爬取数据

二、原理

验证码于服务器端生成，发送给客户端，并以图像格式显示。客户端提交所显示的验证码，客户端接收并进行比较，若比对失败则不能实现登录或注册，反之成功后跳转相应界面。
流程
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三、如何实现

1、前期配置

1. 安装pillow

   pip install Pillow
   

2. 安装django-simple-captcha

   pip install  django-simple-captcha==0.5.6
   

3. 将captcha添加到setting的app中

   INSTALLED_APPS = [
       'captcha',
   ]
   

4. 添加urls.py

   urlpatterns += [
       url(r'^captcha/', include('captcha.urls')),
   ]
   

5. 配置

   # django_simple_captcha 验证码配置   
   # 格式  
   CAPTCHA_OUTPUT_FORMAT = u'%(text_field)s %(hidden_field)s %(image)s'  
   # 噪点样式  
   CAPTCHA_NOISE_FUNCTIONS = ('captcha.helpers.noise_null', # 没有样式  
       # 'captcha.helpers.noise_arcs', # 线  
       # 'captcha.helpers.noise_dots', # 点  
   )  
   # 图片大小  
   CAPTCHA_IMAGE_SIZE = (100, 25)  
   CAPTCHA_BACKGROUND_COLOR = '#ffffff'  
   CAPTCHA_CHALLENGE_FUNCT = 'captcha.helpers.random_char_challenge' # 图片中的文字为随机英文字母，如 mdsh  
   # CAPTCHA_CHALLENGE_FUNCT = 'captcha.helpers.math_challenge'    # 图片中的文字为数字表达式，如1+2=  
   CAPTCHA_LENGTH = 4 # 字符个数  
   CAPTCHA_TIMEOUT = 1 # 超时(minutes)  
   

2、示例代码

1. forms.py

   from django import forms
   from maiziedu.models import UserProfile
   from captcha.fields import CaptchaField
   class RegisterForm(forms.Form):
       '''
       注册
       '''
   username = forms.EmailField(widget=forms.TextInput(attrs={"placeholder": "请输入邮箱账号", "value": "", "required": "用户名不能为空",}),max_length=50,error_messages={"required": "用户名不能为空",})
    password = forms.CharField(widget=forms.PasswordInput(attrs={"placeholder": "请输入密码", "value": "", "required": "密码不能为空",}),min_length=8, max_length=50,error_messages={"required": "密码不能为空",})
       # 验证码
       captcha = CaptchaField()
       def clean(self):
           # 验证码
           try:            
               captcha_x = self.cleaned_data['captcha']            
           except Exception as e:
               raise forms.ValidationError(u"验证码有误，请重新输入")
            # 用户名
           try:
               username=self.cleaned_data['username']
           except Exception as e:
               raise forms.ValidationError(u"注册账号需为邮箱格式")    
           # 登录验证        
           is_email_exist = UserProfile.objects.filter(email=username).exists() 
           is_username_exist = UserProfile.objects.filter(username=username).exists() 
           if is_username_exist or is_email_exist:
               raise forms.ValidationError(u"该账号已被注册")
           # 密码
           try:
               password=self.cleaned_data['password']
           except Exception as e:
               raise forms.ValidationError(u"请输入至少8位密码");
           return self.cleaned_data 
   

2. 刷新验证码

   # 刷新验证码  
   def refresh_captcha(request):  
       verify= dict()  
       verify['cptch_key'] = CaptchaStore.generate_key()  
       verify['cptch_image'] = verify(to_json_response['cptch_key'])  
       return HttpResponse(json.dumps(verify), content_type='application/json')  
   

3. views.py

   def register(request):  
       if request.method == 'POST':  
           # 验证码  
           try:  
               reg_form = RegisterForm(request.POST)  
           except Exception as e:  
               # 登录失败 返回错误提示      
               err = "注册失败，请重试"  
               return result_response(request, err)   
           if reg_form.is_valid():  
               try:  
                   username = reg_form.cleaned_data['username']  
                   password = reg_form.cleaned_data['password']  
                   user = UserProfile.objects.create(username = username, email = username,   
                   password = make_password(password), is_active = True)  
                   user.save()  
                   # 验证成功登录  
                   auth.login(request, user)  
                   return result_response(request, "")  
               except Exception as e:  
                   setFormTips(reg_form, "注册失败，请重试")  
           else:  
               if request.POST.get('captcha_1') == "":  
                   setFormTips(reg_form, "验证码不能为空")   
           # 登录失败 返回错误提示      
           err = getFormTips(reg_form)  
           return result_response(request, err)   
       else:  
           reg_form = RegisterForm()  
           #  locals() 传递所有变量
       return render(request, 'index.html', locals())  
   

4. 刷新验证码

       $(function () {
               let refres_url = 'http://127.0.0.1:8000/account/verify/';
               $('.captcha').click(function () {
                   $.getJSON(refres_url, function (data) {
                       $('.captcha').attr('src', data.img_url)
                       $('#id_capt_0').val(data.haskey)
                   })
               })
           })
   

   ​