如何修复Django Singleton模型的“名称'self'未定义”

时间：2019-06-11 23:58:03

标签： django django-models django-templates django-views trumbowyg

我正在尝试使用Django v1.11和Trumbowyg在我的网站上为用户创建可编辑的帮助页面。我想要完成的是：

  1. 仅允许超级用户通过对他们可见的按钮来编辑页面
  2. 使用Trumbowyg编辑器输入和编辑文本
  3. 保存该文本，然后在页面上将其显示为html

自然地，我认为我应该为HelpText创建一个模型，该模型将保存放入Trumbowyg编辑器中的文本。但是，此模型必须特殊，因为其中只有一个。所以我转向了单例模型。我遵循了tutorial，并创建了SingletonModel模型，并将其子类化为我的HelpText模型。

class SingletonModel(models.Model):

    class Meta:
        abstract = True

    def save(self, *args, **kwargs):
        self.pk = 1
        super(HelpText, self).save(*args, **kwargs)


    def delete(self, *args, **kwargs):
        pass

    @classmethod
    def load(cls):
         obj, created = cls.objects.get_or_create(pk=1)
         return obj

class HelpText(SingletonModel):
    text = models.TextField(blank=True)

但是，在将HelpText注册到我的admin.py之后，这给了我一个错误。

the model s is abstract so it cannot be registered with admin.' model.__name__

通过几次Google搜索，我发现问题是在Meta类中，abstract设置为true。我无法弄清楚如何消除此错误，所以我想：“嘿！如果问题是摘要设置为true，则完全核对SingletonModel类，然后将其方法放入HelpText中。”所以我做到了。

class HelpText(models.Model):

    text = models.TextField(blank=True)

    def save(self, *args, **kwargs):
        self.pk = 1
        super(HelpText, self).save(*args, **kwargs)


    def delete(self, *args, **kwargs):
        pass

    @classmethod
    def load(cls):
        obj, created = cls.objects.get_or_create(pk=1)
        return obj

    def __str__(self):
        return self.help_text

令人惊讶的是，我对此也犯了一个错误，但种类繁多。现在，Django告诉我，当我加载帮助页面时，“未定义名称'self'。”考虑到我还有其他几个使用def__str __（self）定义其字符串方法并公然使用self引用其自身字段的模型，我不知道这是怎么可能的。这是怎么回事？该错误也发生在help_text = webapp_models.HelpText.load()行的views.py中的help_landing方法中。与该模型相关的视图和模板如下。

views.py 

@login_required(login_url=LEADER_LOGIN_URL)
def help_landing(request):
    # Variable to decide if the edit button exists on the help_landing page
    super_can_edit = is_superuser(request.user)
    help_text = webapp_models.HelpText.load()

    context = {
        'include_back': True,
        'include_home': True,
        'description': 'Help',
        'super_can_edit': super_can_edit,
        'help_text': help_text,
    }

    return render(request, 'leader/help_landing.html', context)

@login_required(login_url=LEADER_LOGIN_URL)
def help_create_landing(request):
    help_text = webapp_models.HelpText.load()

    context = {
        'include_back': True,
        'include_home': True,
        'description': 'Help Edit',
        'help_text': help_text,
    }

    return render(request, 'leader/help_create_landing', context)

@login_required(login_url=LEADER_LOGIN_URL)
def help_create(request):

    help_text = webapp_models.HelpText.load()

    help_text.update(
        text=request.POST['text'],
        )

    help_text.save()

    return redirect('leader/help_landing')

help_landing.html 

{% extends "leader/base.html" %}

{% block extra_css %}
<style>

button {
    background-color: Transparent;
    background-repeat: no-repeat;
    border: none;
    cursor: pointer;
    overflow: hidden;
    outline: none;
}

</style>
{% endblock %}

{% block description %}{{ description }}{% endblock %}

{% block content %}

<div class="ui grid"> 
    <div class="eight wide column"> 
        {% if help_text %}{{ help_text.text }}{% endif %}
    </div>
    {% if super_can_edit %} 
    <div class="six wide column"> 
        <a href="leader/help_create_landing/"> 
            <button class="customButton" type="submit">
              <h2 class="ui header">
                  <i class="big circle add icon"></i>
                    Edit Help Page
              </h2>
            </button>
        </a>
    </div>
    {% endif %}

</div>

{% block javascript %}
<script>

</script>
{% endblock %}

help_create_landing.html 

{% extends "leader/base.html" %}

{% block extra_css %}
<style>

button {
    background-color: Transparent;
    background-repeat: no-repeat;
    border: none;
    cursor: pointer;
    overflow: hidden;
    outline: none;
}

</style>
{% endblock %}

{% block description %}{{ description }}{% endblock %}

{% block content %}

<div class="column">
    <form name="helpForm" action="/leader/help_create/" method="post" role="form" enctype="multipart/form-data">{% csrf_token %}
        <div class="ui grid"> 
            <div class="six wide column"> 
                <textarea id="helpEditor" name="text" rows=6 type="text">
                    {% if help_text %}{{ help_text.text }}{% endif %}
                </textarea>
            </div>
            <div class="six wide column"> 
                <button type="submit" id="save">Edit</button>
            </div>
        </div>
    </form>
</div>

{% block javascript %}
<script>
    $(helpEditor).trumbowyg();
</script>


{% endblock %}

跟踪：出于安全原因，我要关闭网站名称

Environment:


Request Method: GET
Request URL: https://fdev.com/leader/help_landing/

Django Version: 1.11.4
Python Version: 3.5.2
Installed Applications:
['webapp.apps.WebappConfig',
 'leader.apps.LeaderConfig',
 'rest_framework',
 'django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'channels']
Installed 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']



Traceback:

File "/home/felix/felix_env/lib/python3.5/site-packages/django/core/handlers/exception.py" in inner
  41.             response = get_response(request)

File "/home/felix/felix_env/lib/python3.5/site-packages/django/core/handlers/base.py" in _get_response
  187.                 response = self.process_exception_by_middleware(e, request)

File "/home/felix/felix_env/lib/python3.5/site-packages/channels/handler.py" in process_exception_by_middleware
  243.             return super(AsgiHandler, self).process_exception_by_middleware(exception, request)

File "/home/felix/felix_env/lib/python3.5/site-packages/django/core/handlers/base.py" in _get_response
  185.                 response = wrapped_callback(request, *callback_args, **callback_kwargs)

File "/home/felix/felix_env/lib/python3.5/site-packages/django/contrib/auth/decorators.py" in _wrapped_view
  23.                 return view_func(request, *args, **kwargs)

File "/home/felix/felixserver/leader/views.py" in help_landing
  1892.     help_text = webapp_models.HelpText.load()

File "/home/felix/felixserver/webapp/models.py" in load


Exception Type: NameError at /leader/help_landing/
Exception Value: name 'self' is not defined

在Django shell中，我可以实例化一个HelpText对象，但是如果创建多个对象，则会出现错误。我相信这是因为我确保应该始终存在一个HelpText模型。这是回溯。

Traceback (most recent call last):
  File "/home/felix/felix_env/lib/python3.5/site-packages/django/db/backends/utils.py", line 65, in execute
    return self.cursor.execute(sql, params)
  File "/home/felix/felix_env/lib/python3.5/site-packages/django/db/backends/sqlite3/base.py", line 328, in execute
    return Database.Cursor.execute(self, query, params)
sqlite3.IntegrityError: UNIQUE constraint failed: webapp_helptext.id

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/home/felix/felix_env/lib/python3.5/site-packages/django/db/models/manager.py", line 85, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/home/felix/felix_env/lib/python3.5/site-packages/django/db/models/query.py", line 394, in create
    obj.save(force_insert=True, using=self.db)
  File "/home/felix/felixserver/webapp/models.py", line 371, in save
    super(HelpText, self).save(*args, **kwargs)
  File "/home/felix/felix_env/lib/python3.5/site-packages/django/db/models/base.py", line 807, in save
    force_update=force_update, update_fields=update_fields)
  File "/home/felix/felix_env/lib/python3.5/site-packages/django/db/models/base.py", line 837, in save_base
    updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields)
  File "/home/felix/felix_env/lib/python3.5/site-packages/django/db/models/base.py", line 923, in _save_table
    result = self._do_insert(cls._base_manager, using, fields, update_pk, raw)
  File "/home/felix/felix_env/lib/python3.5/site-packages/django/db/models/base.py", line 962, in _do_insert
    using=using, raw=raw)
  File "/home/felix/felix_env/lib/python3.5/site-packages/django/db/models/manager.py", line 85, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/home/felix/felix_env/lib/python3.5/site-packages/django/db/models/query.py", line 1076, in _insert
    return query.get_compiler(using=using).execute_sql(return_id)
  File "/home/felix/felix_env/lib/python3.5/site-packages/django/db/models/sql/compiler.py", line 1107, in execute_sql
    cursor.execute(sql, params)
File "/home/felix/felix_env/lib/python3.5/site-packages/django/db/backends/utils.py", line 80, in execute
    return super(CursorDebugWrapper, self).execute(sql, params)
  File "/home/felix/felix_env/lib/python3.5/site-packages/django/db/backends/utils.py", line 65, in execute
    return self.cursor.execute(sql, params)
  File "/home/felix/felix_env/lib/python3.5/site-packages/django/db/utils.py", line 94, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "/home/felix/felix_env/lib/python3.5/site-packages/django/utils/six.py", line 685, in reraise
    raise value.with_traceback(tb)
  File "/home/felix/felix_env/lib/python3.5/site-packages/django/db/backends/utils.py", line 65, in execute
    return self.cursor.execute(sql, params)
  File "/home/felix/felix_env/lib/python3.5/site-packages/django/db/backends/sqlite3/base.py", line 328, in execute
    return Database.Cursor.execute(self, query, params)
django.db.utils.IntegrityError: UNIQUE constraint failed: webapp_helptext.id

0 个答案:

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