Python json.dumps 自定义序列化操作

def login_ajax(request):
    if request.method == "GET":
        return render(request, 'login_ajax.html')
    elif request.method == "POST":
        ret = {'status': True, 'error':None, 'data': None}
        obj = LoginForm(request.POST)
        if obj.is_valid():
            print(obj.clean())
        else:
            # 方式一
            # res_str = obj.errors.as_json() # res_str是一个字符串
            # ret['status'] = False
            # ret['error'] = res_str
            # 两次反序列化
            # 方式二：
            ret['status'] = False
            ret['error'] = obj.errors.as_data() # # {'user': [ValidationError(['用户名长度不能小6'])], 'email': [ValidationError(['邮箱格式错误'])]}
            # # 一次反序列化
        return HttpResponse(json.dumps(ret,cls=JsonCustomEncoder))

from django.core.validators import ValidationError
class JsonCustomEncoder(json.JSONEncoder):
    def default(self, field):
        if isinstance(field, ValidationError):
            return {'code': field.code, 'message': field.message}
        else:
            return json.JSONEncoder.default(self, field)