drf实现图片验证码功能

一.背景

　　在之前实现过django的图片验证码，有自己实现过的，也有基于django-simple-captcha的,都是基于form表单验证，若自己实现，可以获取相应的标签name便可以获取判断，若使用django-simple-captcha只需相应配置即可。但在前后端分离的情况下，就有点摸不着头脑了，序列化时CaptchaField不管作用，百度搜索也没找到相应的办法，于是心想只有重写restframework_jwt自带的登录验证接口及注册接口，都得新增字段。

二.django-simple-captcha简单介绍

　　Django Simple Captcha是一个非常简单但高度可定制的Django应用程序，可以将captcha图像添加到任何Django表单中。

　　网址如下：https://django-simple-captcha.readthedocs.io/en/latest/，只需按照文档简单配置即可，该插件会对应生成一张表，存放验证码信息及过期时间等。

三.基于django-simple-captcha的drf图片验证码

　　1.生成图片验证码接口（我这里将图片转换成了base64），也可以是图片或地址：

from django.http import HttpResponse
from captcha.views import CaptchaStore, captcha_image
import base64
.......
class ImageView(APIView):
    def get(self, request):
        hashkey = CaptchaStore.generate_key()
        try:
        #获取图片id
            id_ = CaptchaStore.objects.filter(hashkey=hashkey).first().id
            imgage = captcha_image(request, hashkey)
        #将图片转换为base64
            image_base = base64.b64encode(imgage.content)
            json_data = json.dumps({"id": id_, "image_base": image_base.decode('utf-8')})
        except:
            json_data = None
        return HttpResponse(json_data, content_type="application/json")                

　　2.注册时的图片验证码：

　　　　2.1序列化：

　　　　这里把图片验证码的id和用户输入的内容都传过来，不易错误，captcha生成的表中的字段expiration是生成图片的时间加五分钟，因此captcha判断的也就是这个过期时间，重写也可以判断这个时间，若当前时间大于它则过期（有效时间五分钟）。

class UserRegSerializer(serializers.ModelSerializer):
    """"
    用户注册序列化
    """
    username = serializers.CharField(min_length=2, max_length=20,
                                     error_messages={
                                         "max_length": "用户名长度应小于等于20",
                                         "min_length": "用户名长度应大于等于2"},
                                     validators=[UniqueValidator(queryset=User.objects.all(), message='用户名已经被使用')],help_text="用户名")
    code = serializers.CharField(required=True, write_only=True, max_length=4, min_length=4, label='验证码',
                                 error_messages={
                                     "blank": "请输入邮箱验证码",
                                     "required": "邮箱验证码不能为空",
                                     "max_length": "邮箱验证码格式错误",
                                     "min_length": "邮箱验证码格式错误"
                                 }, help_text='邮箱验证码')
    email = serializers.CharField(required=True, allow_blank=False,
                                  validators=[UniqueValidator(queryset=User.objects.all(), message='用户已经存在')],help_text="邮箱")
    password = serializers.CharField(style={"input_type": "password"}, write_only=True,help_text="密码")
    captcha = serializers.CharField(min_length=4, max_length=4, required=True,
                                    error_messages={
                                        "max_length": "图片验证码格式错误",
                                        "min_length": "图片验证码格式错误",
                                        "required": "请输入图片验证码"
                                    },help_text="图片验证吗")
    ima_id = serializers.CharField(required=True, write_only=True, allow_blank=False,help_text="图片验证码id")

    def validate_code(self, code):
        verify_codes = EmailVeriyRecord.objects.filter(email=self.initial_data['email']).order_by('-send_time')
        if verify_codes:
            last_verfycode = verify_codes[0]
            five_minute_ago = datetime.now() - timedelta(hours=0, minutes=5, seconds=0)
            if five_minute_ago > last_verfycode.send_time:
                raise serializers.ValidationError('验证码过期')
            if code != last_verfycode.code:
                raise serializers.ValidationError('验证码错误')
        else:
            raise serializers.ValidationError('验证码错误')

    def validate_password(self, password):
        """
          密码长度大于6小于12
        """
        if re.match(REGEX_PWD, password):
            pass
        else:
            raise serializers.ValidationError("密码必须包含数字，字母，特殊符中两到三种，且长度在6-12之间")
        return password

    def validate_captcha(self, captcha):
        try:
            captcha = captcha.lower()
        except:
            raise serializers.ValidationError("图片验证码错误")
        image_code = CaptchaStore.objects.filter(
            id=self.initial_data['ima_id']).first()
        if image_code and datetime.now() > image_code.expiration:
            raise serializers.ValidationError('图片验证码过期')
        else:
            if image_code and image_code.response == captcha:
                pass
            else:
                raise serializers.ValidationError("图片验证码错误")

    # 作用于所有字段
    def validate(self, attrs):
        if attrs['username']:
            pass
        else:
            attrs['username'] = attrs['email']
        del attrs["code"]
        del attrs["ima_id"]
        del attrs["captcha"]
        return attrs

    class Meta:
        model = User
        fields = ('email', 'code', 'password', 'username', 'captcha', 'ima_id')

 　　　　2.2注册view实现：

class UserRegisterViewset(mixins.CreateModelMixin, mixins.UpdateModelMixin,
                          mixins.RetrieveModelMixin, viewsets.GenericViewSet):
    """
       用户注册接口
    create:
        用户添加
    """
    serializer_class = UserRegSerializer
    queryset = User.objects.all()
    authentication_classes = (JSONWebTokenAuthentication, authentication.SessionAuthentication)

    def create(self, request, *args, **kwargs):
        serializer = self.get_serializer(data=request.data)
        serializer.is_valid(raise_exception=True)
        user = self.perform_create(serializer)
        re_dict = serializer.data
        payload = jwt_payload_handler(user)
        re_dict['token'] = jwt_encode_handler(payload)
        headers = self.get_success_headers(serializer.data)
        return Response(re_dict, status=status.HTTP_201_CREATED, headers=headers)

    def get_serializer_class(self):
        '''
        重载GenericAPIView中的get_serializer_class函数，调用不同的序列化类，如果是create,
        就调用UserRegSerializer序列化，否则UserDetailSerializer序列化
        :return: 
        '''
        if self.action == 'retrieve':
            return UserDetailSerializer
        elif self.action == 'create':
            return UserRegSerializer
        return UserDetailSerializer

    def get_permissions(self):
        '''
        重载APIview中的get_perimissions函数，如果是新增用户则不用登录，否则必须登录
        :return: 
        '''
        if self.action == 'retrieve':
            return [permissions.IsAuthenticated()]
        elif self.action == 'create':
            return []
        return []

    def get_object(self):
        '''
        返回当前用户
        :return: 
        '''
        return self.request.user

    def perform_create(self, serializer):
        return serializer.save()

 　　2.登录：

　　　　2.1序列化：

from rest_framework_jwt.settings import api_settings

jwt_payload_handler = api_settings.JWT_PAYLOAD_HANDLER
jwt_encode_handler = api_settings.JWT_ENCODE_HANDLER
from django.contrib.auth import authenticate
from rest_framework_jwt.compat import PasswordField


class MyloginSerializer(JSONWebTokenSerializer):
    """
    从写登录序列化
    """

    def __init__(self, *args, **kwargs):
        """
        Dynamically add the USERNAME_FIELD to self.fields.
        """
        super(JSONWebTokenSerializer, self).__init__(*args, **kwargs)

        self.fields[self.username_field] = serializers.CharField()
        self.fields['password'] = PasswordField(write_only=True)
        self.fields['captcha'] = serializers.CharField(min_length=4, max_length=4, required=True,
                                                       error_messages={
                                                           "max_length": "图片验证码格式错误",
                                                           "min_length": "图片验证码格式错误",
                                                           "required": "请输入图片验证码"
                                                       })
        self.fields['ima_id'] = serializers.CharField(required=True, allow_blank=False)

    def validate_captcha(self, captcha):
        image_code = CaptchaStore.objects.filter(
            id=self.initial_data['ima_id']).first()
        five_minute_ago = datetime.now() - timedelta(hours=0, minutes=5, seconds=0)
        if image_code and five_minute_ago > image_code.expiration:
            raise serializers.ValidationError('验证码过期')
        else:
            if image_code and (image_code.response == captcha or image_code.challenge == captcha):
                pass
            else:
                raise serializers.ValidationError("图片验证码错误")

    def validate(self, attrs):
        del attrs["ima_id"]
        del attrs["captcha"]
        credentials = {
            self.username_field: attrs.get(self.username_field),
            'password': attrs.get('password')
        }

        if all(credentials.values()):
            user = authenticate(**credentials)

            if user:
                if not user.is_active:
                    msg = _('User account is disabled.')
                    raise serializers.ValidationError(msg)

                payload = jwt_payload_handler(user)

                return {
                    'token': jwt_encode_handler(payload),
                    'user': user
                }
            else:
                msg = _('Unable to log in with provided credentials.')
                raise serializers.ValidationError(msg)
        else:
            msg = _('Must include "{username_field}" and "password".')
            msg = msg.format(username_field=self.username_field)
            raise serializers.ValidationError(msg)

　　　　2.2view：

from rest_framework_jwt.views import JSONWebTokenAPIView
from .serializers import MyloginSerializer

class MyJSONWebToken(JSONWebTokenAPIView):
    """"
    重写jwt的登录验证，含图片验证码
    """
    serializer_class = MyloginSerializer

　　3.url中相应配置：

    url(r'images/$',ImageView.as_view()),
    url(r'login/$',MyJSONWebToken.as_view(),name="login")

四.总结

　　这样做功能是实现了，但感觉有些粗糙，可以把验证码表的数据超过某个时间的自动清除，也可以把数据放入缓存（redis等），希望能提一些改进的建议。