Django基于类的视图，get_absolute_url不起作用 [英] Django Class Based Views, get_absolute_url not working

问题描述

我购买并正在阅读《 Django的两个独家消息:Django 1.5的最佳实践》一书，其中有一个基于类的视图示例.完成此操作后，提交表单后出现错误.

I bought and am Reading the Book Two Scoops of Django:Best Practices for Django 1.5 and in it has a example of Class based views. After this implementation I get the error after submitting the form.

ImproperlyConfigured at /NonProfitCreate/
No URL to redirect to.  Either provide a url or define a get_absolute_url method on the Model

做研究时，我遇到了这个问题 Django-基于类的通用视图-没有要重定向到的URL"

Doing research I came along this problem Django - Class Based Generic View - "No URL to redirect to"

我希望get_absolute_url在我的程序中工作

I want the get_absolute_url to work in my program

这是我的表格.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
#  npp/forms.py

from django import forms

from .models import NonProfit

class NonProfitCreateForm(forms.ModelForm):
    class Meta:
        model = NonProfit
        fields = ("name","contact_name","email","phone","address","image","tags",)

    def __init__(self, *args, **kwargs):
        self.request = kwargs.pop('request', None)
        return super(NonProfitCreateForm, self).__init__(*args, **kwargs)

    def save(self, *args, **kwargs):
        kwargs['commit']=False
        obj = super(NonProfitCreateForm, self).save(*args, **kwargs)
        if self.request:
            obj.user = self.request.user
            obj.save()

class NonProfitUpdateForm(NonProfitCreateForm):
    class Meta:
        model = NonProfit

这是我的models.py和视图文件

this is my models.py and views files

from django.db import models
from django.contrib.auth.models import User
from django.db.models import permalink
from django_extensions.db.fields import AutoSlugField
from django.contrib import admin

from django.core.urlresolvers import reverse

import tagging
from tagging.models import Tag
# Create your models here.
''' this is for the Non-Profit Proccess '''

class NonProfit (models.Model):
    User = models.ForeignKey(User)
    name = models.CharField(max_length=100)
    contact_name = models.CharField(max_length=100)
    email = models.EmailField(max_length=75)
    phone = models.CharField(max_length=20)
    address = models.TextField(max_length=3000)
    image = models.ImageField(upload_to='photos/%Y/%m/%d',blank=True)


    slug = models.SlugField(max_length=128)
    slug = AutoSlugField(('slug'), max_length=128, unique=True, populate_from=('name',))
    tags = tagging.fields.TagField()

    def get_absolute_url(self):
        return reverse("npp/nonprofit_detail", kwargs={"slug": self.slug})  

    def __unicode__(self):
        return self.name

    def get_tags(self):
        return Tag.objects.get_for_object(self)




  # Create your views here.
    # Auction/npp/views.py

from Auction.views import ActionMixin

from django.contrib import messages
from django.views.generic import CreateView, UpdateView, DetailView

from braces.views import LoginRequiredMixin

from forms import NonProfitCreateForm,NonProfitUpdateForm


from models import NonProfit

class NonProfitCreateView(LoginRequiredMixin,ActionMixin,CreateView):
    model = NonProfit
    action = "created"
    form_class = NonProfitCreateForm

class NonProfitUpdateView(LoginRequiredMixin,ActionMixin,UpdateView):
    model = NonProfit
    action = "updated"
    form_class = NonProfitUpdateForm


class NonProfitDetailView(DetailView):
    model = NonProfit


# Auction/views.py
class ActionMixin(object):
    @property
    def action(self):
        msg = "{0} is missing action.".format(self.__class__)
        raise NotImplementedError(msg)

    def form_valid(self, form):
        msg = "{0}!".format(self.action)
        messages.info(self.request, msg)
        return super(ActionMixin, self).form_valid(form)

urls.py

url(
    regex=r'^NonProfitCreate/',
    view=NonProfitCreateView.as_view(),
    name='NonProfitCreate',
),
url(
    regex=r'^NonProfit/(?P<slug>[-\w\d]+)/',
    view=NonProfitDetailView.as_view(),
    name='NonProfit'
    )

这是我的堆栈跟踪，突出显示了django括号，然后

this is my stacktrace, the django braces is highlighted, and

/home/talisman/projects/Auction/Auction/views.py in form_valid
        return super(ActionMixin, self).form_valid(form) 

EEnvironment:


Request Method: POST
Request URL: http://127.0.0.1:8000/NonProfitCreate/

Django Version: 1.5.1
Python Version: 2.7.4
Installed Applications:
('django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.sites',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'django.contrib.admin',
 'django.contrib.admindocs',
 'django.contrib.comments',
 'django.contrib.sitemaps',
 'zinnia',
 'tagging',
 'mptt',
 'south',
 'misc',
 'adm',
 'registration',
 'npp',
 'blogs')
Installed Middleware:
('django.middleware.common.CommonMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware')


Traceback:
File "/home/talisman/virt_env/Auction/local/lib/python2.7/site-packages/Django-1.5.1-py2.7.egg/django/core/handlers/base.py" in get_response
  115.                         response = callback(request, *callback_args, **callback_kwargs)
File "/home/talisman/virt_env/Auction/local/lib/python2.7/site-packages/Django-1.5.1-py2.7.egg/django/views/generic/base.py" in view
  68.             return self.dispatch(request, *args, **kwargs)
File "/home/talisman/virt_env/Auction/local/lib/python2.7/site-packages/django_braces-1.0.0-py2.7.egg/braces/views.py" in dispatch
  98.             **kwargs)
File "/home/talisman/virt_env/Auction/local/lib/python2.7/site-packages/Django-1.5.1-py2.7.egg/django/views/generic/base.py" in dispatch
  86.         return handler(request, *args, **kwargs)
File "/home/talisman/virt_env/Auction/local/lib/python2.7/site-packages/Django-1.5.1-py2.7.egg/django/views/generic/edit.py" in post
  199.         return super(BaseCreateView, self).post(request, *args, **kwargs)
File "/home/talisman/virt_env/Auction/local/lib/python2.7/site-packages/Django-1.5.1-py2.7.egg/django/views/generic/edit.py" in post
  165.             return self.form_valid(form)
File "/home/talisman/projects/auction/Auction/views.py" in form_valid
  54.       return super(ActionMixin, self).form_valid(form)
File "/home/talisman/virt_env/Auction/local/lib/python2.7/site-packages/Django-1.5.1-py2.7.egg/django/views/generic/edit.py" in form_valid
  128.         return super(ModelFormMixin, self).form_valid(form)
File "/home/talisman/virt_env/Auction/local/lib/python2.7/site-packages/Django-1.5.1-py2.7.egg/django/views/generic/edit.py" in form_valid
  65.         return HttpResponseRedirect(self.get_success_url())
File "/home/talisman/virt_env/Auction/local/lib/python2.7/site-packages/Django-1.5.1-py2.7.egg/django/views/generic/edit.py" in get_success_url
  119.                     "No URL to redirect to.  Either provide a url or define"

Exception Type: ImproperlyConfigured at /NonProfitCreate/
Exception Value: No URL to redirect to.  Either provide a url or define a get_absolute_url method on the Model.

推荐答案

之所以产生此异常，是因为在有效的编辑后尝试重定向时 self.object = None .由于 self.object 的值是 form.save()调用的结果，因此出现此错误的最可能原因是您覆盖了 save()方法在 NonProfitCreateForm 中，但是忘记了返回保存的对象.

This exception is produced because self.object = None when attempting to redirect after a valid edit. Since the value of self.object is the result of a form.save() call, the most likely reason for this error is that you have overridden the save() method in NonProfitCreateForm, but forgotten to return the saved object.

Form.save()方法应返回已保存的对象，并且不应 None .

The Form.save() method is expected to return the object that was saved and should not be None.

您的 NonProfitCreateForm 可以进行如下修改:

Your NonProfitCreateForm could be modified as shown below:

class NonProfitCreateForm(forms.ModelForm):
    ...
    def save(self, *args, **kwargs):
        kwargs['commit']=False
        obj = super(NonProfitCreateForm, self).save(*args, **kwargs)
        if self.request:
            obj.user = self.request.user
            obj.save()
        return obj #<--- Return saved object to caller.

save()方法的前两行将根据输入的表单数据创建一个模型实例.但是由于 commit = False ，该对象将不保存到数据库中.如果表单实例上不存在 self.request ，则返回的对象将没有数据库主键，并且 get_absolute_url 仍然会失败.

The first two lines of your save() method will create a model instance from the entered form data. But because commit=False, the object will not be saved to the database. If self.request is not present on your form instance, a the returned object will not have a database primary key, and get_absolute_url will still fail.

因此，您要确保在实例化时始终将 request 参数传递给表单.默认情况下不会发生这种情况，因此您需要安排视图代码以使用 request 参数实例化表单.

So, you want to ensure that a request parameter is always passed to your form when instantiated. This doesn't happen by default, so you need to arrange your view code to instantiate your form with a request parameter.

浏览 FormMixin的代码 ，您会看到有一个 get_form_kwargs 函数，该函数确定要传递给任何实例化形式的参数.您需要传递 request = self.request ，因此在您的视图中覆盖 get_form_kwargs 以添加所需的参数，如下所示:

Looking through the code for FormMixin you can see that there is a get_form_kwargs function which determines the arguments to pass to any instantiated form. You need to pass request=self.request, so in your view override get_form_kwargs to add the required parameter, something like this:

class NonProfitCreateView(LoginRequiredMixin,ActionMixin,CreateView):
    model = NonProfit
    action = "created"
    form_class = NonProfitCreateForm

    def get_form_kwargs(self):
        # Ensure the current `request` is provided to NonProfitCreateForm.
        kwargs = super(NonProfitCreateView, self).get_form_kwargs()
        kwargs.update({ 'request': self.request })
        return kwargs

使用修改后的 get_form_kwargs 函数创建 CreateView 的子类，并从您的 NonProfitCreateView 派生出一个更好的主意.子类.

It would probably be a better idea to create a subclass of CreateView with the modified get_form_kwargs function, and have your NonProfitCreateView derive from the subclass.

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