为什么会出现此错误？ AttributeError：“ str”对象没有属性“ decode”

Question

我正在尝试通过电子邮件验证创建注册页面。我是Python Dajngo网络开发的新手。当前，我使用Python 3.6，Django 2.2.4，Postgresql 11和Ubuntu OS。但是我有一个问题，无法解决。你们可以帮我解决问题吗？预先感谢！

我已经提供了以下所有代码：

这是我遇到的错误：

AttributeError at /register/
'str' object has no attribute 'decode'
Request Method: POST
Request URL:    http://127.0.0.1:8000/register/
Django Version: 2.2.4
Exception Type: AttributeError
Exception Value:    
'str' object has no attribute 'decode'
Exception Location: /media/coduser/KAPTRANS/ProgrammingProj-2/test/ChhichhiProject_comment_done/ChhichhiProject/chhichhi_project/users/views.py in register, line 36
Python Executable:  /media/coduser/KAPTRANS/ProgrammingProj-2/test/ChhichhiProject_comment_done/ChhichhiProject/env/chhichhi/bin/python
Python Version: 3.6.8
Python Path:    
['/media/coduser/KAPTRANS/ProgrammingProj-2/test/ChhichhiProject_comment_done/ChhichhiProject/chhichhi_project',
 '/usr/lib/python36.zip',
 '/usr/lib/python3.6',
 '/usr/lib/python3.6/lib-dynload',
 '/media/coduser/KAPTRANS/ProgrammingProj-2/test/ChhichhiProject_comment_done/ChhichhiProject/env/chhichhi/lib/python3.6/site-packages']
Server time:    Wed, 28 Aug 2019 09:37:05 +0000

这是settings.py文件

"""
Django settings for chhichhi_project project.

Generated by 'django-admin startproject' using Django 2.2.3.

For more information on this file, see
https://docs.djangoproject.com/en/2.2/topics/settings/

For the full list of settings and their values, see
https://docs.djangoproject.com/en/2.2/ref/settings/
"""

import os

# Build paths inside the project like this: os.path.join(BASE_DIR, ...)
BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))


# Quick-start development settings - unsuitable for production
# See https://docs.djangoproject.com/en/2.2/howto/deployment/checklist/

# SECURITY WARNING: keep the secret key used in production secret!
SECRET_KEY = "2ba!+2akp+w%d_dfhj)u_@+rg&t8)r$&uyfwza+cza4jv55cyr"

# SECURITY WARNING: don't run with debug turned on in production!
DEBUG = True

ALLOWED_HOSTS = []


# Application definition

INSTALLED_APPS = [
    'users.apps.UsersConfig', # new
    'comments.apps.CommentsConfig', # new
    'blog.apps.BlogConfig', # new    
    'crispy_forms', # 3rd party form styler
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',

]

MIDDLEWARE = [
    'django.middleware.security.SecurityMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.common.CommonMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    'django.middleware.clickjacking.XFrameOptionsMiddleware',
]

ROOT_URLCONF = 'chhichhi_project.urls'

TEMPLATES = [
    {
        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        'DIRS': [],
        'APP_DIRS': True,
        'OPTIONS': {
            'context_processors': [
                'django.template.context_processors.debug',
                'django.template.context_processors.request',
                'django.contrib.auth.context_processors.auth',
                'django.contrib.messages.context_processors.messages',
            ],
        },
    },
]

WSGI_APPLICATION = 'chhichhi_project.wsgi.application'


# Database
# https://docs.djangoproject.com/en/2.2/ref/settings/#databases

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.postgresql',
        'NAME': 'cicidb1',
        'USER': 'postgres',
        'PASSWORD': '1324pass',
        'HOST': 'localhost',
        'PORT': '5432',
    }
}


# Password validation
# https://docs.djangoproject.com/en/2.2/ref/settings/#auth-password-validators

AUTH_PASSWORD_VALIDATORS = [
    {
        'NAME': 'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.MinimumLengthValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.CommonPasswordValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator',
    },
]


# Internationalization
# https://docs.djangoproject.com/en/2.2/topics/i18n/

LANGUAGE_CODE = 'en-us'

TIME_ZONE = 'UTC'

USE_I18N = True

USE_L10N = True

USE_TZ = True


# Static files (CSS, JavaScript, Images)
# https://docs.djangoproject.com/en/2.2/howto/static-files/

STATICFILES_DIRS = [
    os.path.join(BASE_DIR, 'blog/static/')
]

STATIC_ROOT= os.path.join(BASE_DIR, 'static')
STATIC_URL = '/static/'

MEDIA_ROOT = os.path.join(BASE_DIR, 'media')
MEDIA_URL = '/media/'

CRISPY_TEMPLATE_PACK = 'bootstrap4'

LOGIN_REDIRECT_URL = 'blog_home'
LOGIN_URL = 'login'


EMAIL_BACKEND = 'django.core.mail.backends.smtp.EmailBackend'
# my custom local host mail server
EMAIL_HOST = 'smtp.gmail.com'
EMAIL_PORT = 587
EMAIL_USE_TLS = True
EMAIL_HOST_USER = 'youremail@gmail.com'
EMAIL_HOST_PASSWORD = 'yourpassword'
# my custom local host mail server
# EMAIL_HOST = 'smtp.gmail.com'
# EMAIL_PORT =  465
# EMAIL_HOST_USER = 'youremail@gmail.com'
# EMAIL_HOST_PASSWORD = 'yourpassword'
# EMAIL_USE_TLS = False
# EMAIL_USE_SSL = True


# END custom mail server

这是views.py文件

from django.shortcuts import render, redirect
from django.contrib import messages
from django.contrib.auth.decorators import login_required

# Email verification
from django.http import HttpResponse
# from django.shortcuts import render, redirect
from django.contrib.auth import login, authenticate
# from .forms import UserSignUpForm
from .forms import UserRegisterForm, UserUpdateForm, ProfileUpdateForm
from django.contrib.sites.shortcuts import get_current_site
from django.utils.encoding import force_bytes, force_text
from django.utils.http import urlsafe_base64_encode, 
urlsafe_base64_decode
from django.template.loader import render_to_string
from .token_generator import account_activation_token
from django.contrib.auth.models import User
from django.core.mail import EmailMessage
# Email verificatin end


def register(request):
    if request.method == 'POST':
        form = UserRegisterForm(request.POST)
        if form.is_valid():
            user = form.save(commit=False)
            user.is_active = False
            user.save()
            current_site = get_current_site(request)
            email_subject = 'Activate Your Account'
            message = render_to_string('activate_account.html', {
                'user': user,
                'domain': current_site.domain,
                'uid': urlsafe_base64_encode(force_bytes(user.pk)).decode(),
                'token': account_activation_token.make_token(user),
            })
            to_email = form.cleaned_data.get('email')
            email = EmailMessage(email_subject, message, to=[to_email])
            email.send()
            return HttpResponse('We have sent you an email, please confirm your email address to complete registration')
            # username = form.cleaned_data.get('username')
            # messages.success(request, f'Your account has been created! You are now able to log in.')
            # return redirect('login')
    else:
        form = UserRegisterForm()
    return render(request, 'users/register.html',{'form': form})


def activate_account(request, uidb64, token):
    try:
        uid = force_bytes(urlsafe_base64_decode(uidb64))
        user = User.objects.get(pk=uid)
    except(TypeError, ValueError, OverflowError, User.DoesNotExist):
        user = None
    if user is not None and account_activation_token.check_token(user, token):
        user.is_active = True
        user.save()
        login(request, user)
        return HttpResponse('Your account has been activate successfully')
    else:
        return HttpResponse('Activation link is invalid!')

这是urls.py文件

from django.conf.urls import url
from . import views


urlpatterns = [
    url(r'^$', views.register, name='register_user'),
    url(r'^activate/(?P<uidb64>[0-9A-Za-z_\-]+)/(?P<token>[0-9A-Za-z]{1,13}-[0-9A-Za-z]{1,20})/$',
        views.activate_account, name='activate'),
]

这是token_generator.py文件

from django.contrib.auth.tokens import PasswordResetTokenGenerator
from django.utils import six


class TokenGenerator(PasswordResetTokenGenerator):
    def _make_hash_value(self, user, timestamp):
        return (
            six.text_type(user.pk) + six.text_type(timestamp) + six.text_type(user.is_active)
        )


account_activation_token = TokenGenerator()

这是主要的urls.py文件

from django.contrib import admin
from django.contrib.auth import views as auth_views
from django.urls import path, include
from django.conf import settings
from django.conf.urls.static import static
from users import views as user_views

urlpatterns = [
    path('admin/', admin.site.urls),
    # path('register/', user_views.register, name='register'),
    path('register/', include('users.urls')), # new url
    path('profile/', user_views.profile, name='profile'),
    path('login/', auth_views.LoginView.as_view(template_name = 'users/login.html'), name='login'),
    path('logout/', auth_views.LogoutView.as_view(template_name = 'users/logout.html'), name='logout'),
    path('password-reset/', 
            auth_views.PasswordResetView.as_view(template_name = 'users/password_reset.html'), 
            name='password_reset'),
    path('password-reset/done/', 
            auth_views.PasswordResetDoneView.as_view(template_name = 'users/password_reset_done.html'), 
            name='password_reset_done'),
    path('password-reset-confirm/<uidb64>/<token>/', 
            auth_views.PasswordResetConfirmView.as_view(template_name = 'users/password_reset_confirm.html'), 
            name='password_reset_confirm'),
    path('password-reset-complete/', 
                auth_views.PasswordResetCompleteView.as_view(template_name = 'users/password_reset_complete.html'), 
                name='password_reset_complete'),
    path('', include('blog.urls')),

]

if settings.DEBUG:
    urlpatterns += static(settings.STATIC_URL, document_root=settings.STATIC_ROOT)
    urlpatterns += static(settings.MEDIA_URL, document_root=settings.MEDIA_ROOT)

这是register.html文件

{% extends 'blog/base.html' %}
{% load crispy_forms_tags %}
{% block title %}Registration{% endblock title %}

{% block content %}
    <div class="content-section">
        <form method="POST">
            {% csrf_token %}
            <fieldset class="form-group">
                 <legend class="border-bottom mb-4">Join Today</legend>
                 {{ form|crispy }}
            </fieldset>
            <div class="form-group">
                <button class="btn btn-outline-info" type="submit">Sign Up</button>
            </div>
        </form>
        <div class="border-top pt-3">
            <small class="text-muted">
                Already Have An Account? <a class="ml-2" href="{% url 'login' %}">Sign In</a>
            </small>
        </div>
    </div>
{% endblock content %}

Answer 1

您应该学习阅读错误记录，通常它们会告诉您发生了什么。

在这种情况下，错误位置（Exception Location）是该行

'uid': urlsafe_base64_encode(force_bytes(user.pk)).decode()

并且错误为str类型没有属性decode，这表示

urlsafe_base64_encode(force_bytes(user.pk))

显然是str，而不是字节字符串，因此您不能对其应用方法decode。下一步是检查documentation for urlsafe_base64_encode，您将在Django 2.2中看到它返回str。

太好了！因此，使用Django 2.2，无需解码以前的bytestring，只需将您从urlsafe_base64_encode获得的字符串直接传递到邮件模板即可。