Python 第8章-添加页面问题

我目前正在学习Django探戈教程，完成第8章：

最后一个问题是add_页面表单处理的url不是以“http://”开头的，我不太清楚为什么。实际的web应用程序不会出现错误，如果我没有将“请输入URL”工具提示窗口包含在URL中，我只需获取该窗口，并在我自己添加“http://”后正确处理

这些是我的文件：

#VIEWS.PY

from django.http import HttpResponse
from django.shortcuts import render
from rango.models import Category
from rango.models import Page
from rango.forms import CategoryForm
from rango.forms import PageForm

def index(request):
    # Query the database for a list of ALL categories currently stored.
    # Order the categories by no. likes in descending order.
    # Retrieve the top 5 only - or all if less than 5.
    # Place the list in our context_dict and dictionary which will be passed to the template engine.
    category_list = Category.objects.order_by('-likes')[:5]
    page_list = Page.objects.order_by('-views')[:5]
    context_dict = {'categories': category_list, 'pages': page_list}

    # Render the response and send it back!
    return render(request, 'rango/index.html', context_dict)

def about(request):
    context_dict = {'italicmessage': "I am italicised font from the context"}
    return render(request, 'rango/about.html', context_dict)

def category(request, category_name_slug):

    # Create a context dictionary which we can pass to the template rendering engine
    context_dict = {}

    try:
        # Can we find a category name slug with the given name?
        # If we can't, the .get() method raises a DoesNotExist exception.
        # So the .get() method returns one model instance or raises an exception.
        category = Category.objects.get(slug=category_name_slug)
        context_dict['category_name'] = category.name

        # Retrieve all the associated pages.
        # Note that filter returns >= 1 model instance.
        pages = Page.objects.filter(category=category)

        # Adds our results list to the template context under name pages.
        context_dict['pages'] = pages
        # We also add the category object from the database to the context dictionary.
        # We'll use this in the template to verify that the category exists.
        context_dict['category'] = category
        context_dict['category_name_slug'] = category_name_slug

    except Category.DoesNotExist:
        # We get here if we didn't find the specified category.
        # Don't do anything - the template displayes the "no category message for us."
        pass

    # Go render the response and return it to the client.
    return render(request, 'rango/category.html', context_dict)

def add_category(request):
    # A HTTP POST?
    if request.method == 'POST':
        form = CategoryForm(request.POST)

        # Have we been provided with a valid form?
        if form.is_valid():
            # save the new category to the database.
            form.save(commit=True)

            # Now call the index() view.
            # The user will be shown the homepage.
            return index(request)
        else:
            # The supplied form contained errors - just print them to the terminal.
            print form.errors
    else:
        # If the request was not a POST, display the form to enter details.
        form = CategoryForm()

    # Bad form (or form details), no form supplied...
    # Render the form with error messages (if any).
    return render(request, 'rango/add_category.html', {'form': form})

def add_page(request, category_name_slug):

    try:
        cat = Category.objects.get(slug=category_name_slug)
    except Category.DoesNotExist:
        cat = None

    if request.method == 'POST':
        form = PageForm(request.POST)
        if form.is_valid():
            if cat:
                page = form.save(commit=False)
                page.category = cat
                page.views = 0
                page.save()
                return category(request, category_name_slug)
    else:
        form = PageForm()

    context_dict = {'form': form, 'category': cat, 'category_name_slug': category_name_slug}

    return render(request, 'rango/add_page.html', context_dict)

而且

# FORMS.PY

from django import forms
from rango.models import Page, Category

class CategoryForm(forms.ModelForm):
    name = forms.CharField(max_length=128, help_text="Please enter the category name.")
    views = forms.IntegerField(widget=forms.HiddenInput(), initial=0)
    likes = forms.IntegerField(widget=forms.HiddenInput(), initial=0)
    slug = forms.CharField(widget=forms.HiddenInput(), required=False)

    # An inline class to provide additional information on the form.
    class Meta:
        # Provide an association between the ModelForm and a model
        model = Category
        fields = ('name',)

class PageForm(forms.ModelForm):
    title = forms.CharField(max_length=128, help_text="Please enter the title of the page.")
    url = forms.URLField(max_length=200, help_text="Please enter the URL of the page.")
    views = forms.IntegerField(widget=forms.HiddenInput(), initial=0)

    class Meta:
        model = Page
        exclude = ('category',)
                # or specify the fields to include (.i.e. not include the category field)
        #fields = ('title', 'url', 'views')

    def clean(self):
        cleaned_data = self.cleaned_data
        url = cleaned_data.get('url')

        # If url is not empty and doesn't start with 'http://', prepend 'http://'.
        if url and not url.startswith('http://'):
            url = 'http://' + url
            cleaned_data['url'] = url

        return cleaned_data

我怀疑这与forms.py中的PageForm类有关，但我似乎刚刚复制了教程中所示的代码

---

提前感谢您的帮助

快速查看一下Django源代码，就会发现为什么会发生这种情况：

在core/validators.py中

class URLField(CharField):
    default_validators = [validators.URLValidator()]
    description = _("URL")

您可以看到

URLField

的默认验证器是

urlvalidater

，它可以在core/validators.py中找到：

@deconstructible
class URLValidator(RegexValidator):
    regex = re.compile(
        r'^(?:[a-z0-9\.\-]*)://'  # scheme is validated separately
        r'(?:(?:[A-Z0-9](?:[A-Z0-9-]{0,61}[A-Z0-9])?\.)+(?:[A-Z]{2,6}\.?|[A-Z0-9-]{2,}(?<!-)\.?)|'  # domain...
        r'localhost|'  # localhost...
        r'\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}|'  # ...or ipv4
        r'\[?[A-F0-9]*:[A-F0-9:]+\]?)'  # ...or ipv6
        r'(?::\d+)?'  # optional port
        r'(?:/?|[/?]\S+)$', re.IGNORECASE)
    message = _('Enter a valid URL.')
    schemes = ['http', 'https', 'ftp', 'ftps']

    def __init__(self, schemes=None, **kwargs):
        super(URLValidator, self).__init__(**kwargs)
        if schemes is not None:
            self.schemes = schemes

    def __call__(self, value):
        value = force_text(value)
        # Check first if the scheme is valid
        scheme = value.split('://')[0].lower()
        if scheme not in self.schemes:
            raise ValidationError(self.message, code=self.code)

        # Then check full URL
        try:
            super(URLValidator, self).__call__(value)
        except ValidationError as e:
            # Trivial case failed. Try for possible IDN domain
            if value:
                scheme, netloc, path, query, fragment = urlsplit(value)
                try:
                    netloc = netloc.encode('idna').decode('ascii')  # IDN -> ACE
                except UnicodeError:  # invalid domain part
                    raise e
                url = urlunsplit((scheme, netloc, path, query, fragment))
                super(URLValidator, self).__call__(url)
            else:
                raise
        else:
            url = value

@deconstructable
类URLValidator（RegexValidator）：
regex=re.compile(
r'^（？[a-z0-9\.\-]*）：/'#方案单独验证
r'（？：（？：[A-Z0-9]（？：[A-Z0-9-]{0,61}[A-Z0-9]）？\+（？：[A-Z]{2,6}.？；[A-Z0-9-]{2，}（？u调用

它用

方案=值分割提供的输入。分割（'://'）[0]。下（）

获取前缀。如果不想使用此前缀，最好是创建自己的自定义验证。您可能需要阅读：以了解更多信息。

快速查看Django源代码，了解发生这种情况的原因：

在core/validators.py中

class URLField(CharField):
    default_validators = [validators.URLValidator()]
    description = _("URL")

您可以看到

URLField

的默认验证器是

urlvalidater

，它可以在core/validators.py中找到：

@deconstructible
class URLValidator(RegexValidator):
    regex = re.compile(
        r'^(?:[a-z0-9\.\-]*)://'  # scheme is validated separately
        r'(?:(?:[A-Z0-9](?:[A-Z0-9-]{0,61}[A-Z0-9])?\.)+(?:[A-Z]{2,6}\.?|[A-Z0-9-]{2,}(?<!-)\.?)|'  # domain...
        r'localhost|'  # localhost...
        r'\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}|'  # ...or ipv4
        r'\[?[A-F0-9]*:[A-F0-9:]+\]?)'  # ...or ipv6
        r'(?::\d+)?'  # optional port
        r'(?:/?|[/?]\S+)$', re.IGNORECASE)
    message = _('Enter a valid URL.')
    schemes = ['http', 'https', 'ftp', 'ftps']

    def __init__(self, schemes=None, **kwargs):
        super(URLValidator, self).__init__(**kwargs)
        if schemes is not None:
            self.schemes = schemes

    def __call__(self, value):
        value = force_text(value)
        # Check first if the scheme is valid
        scheme = value.split('://')[0].lower()
        if scheme not in self.schemes:
            raise ValidationError(self.message, code=self.code)

        # Then check full URL
        try:
            super(URLValidator, self).__call__(value)
        except ValidationError as e:
            # Trivial case failed. Try for possible IDN domain
            if value:
                scheme, netloc, path, query, fragment = urlsplit(value)
                try:
                    netloc = netloc.encode('idna').decode('ascii')  # IDN -> ACE
                except UnicodeError:  # invalid domain part
                    raise e
                url = urlunsplit((scheme, netloc, path, query, fragment))
                super(URLValidator, self).__call__(url)
            else:
                raise
        else:
            url = value

@deconstructable
类URLValidator（RegexValidator）：
regex=re.compile(
r'^（？[a-z0-9\.\-]*）：/'#方案单独验证
r'（？：（？：[A-Z0-9]（？：[A-Z0-9-]{0,61}[A-Z0-9]）？\+（？：[A-Z]{2,6}.？；[A-Z0-9-]{2，}（？u调用

它用

方案=值分割提供的输入。分割（'://'）[0]。下（）

获取前缀。如果您不想使用此前缀，最好是创建自己的自定义验证。您可能需要阅读：了解更多信息。

URL字段使用

URLValidator

进行验证。 来源：

scheme = value.split('://')[0].lower()
if scheme not in self.schemes:
    raise ValidationError(self.message, code=self.code)

默认情况下：

schemes = ['http', 'https', 'ftp', 'ftps']

所以很明显，只允许绝对URL

---

另请参见。

URLField使用

URLValidator

进行验证。 来源：

scheme = value.split('://')[0].lower()
if scheme not in self.schemes:
    raise ValidationError(self.message, code=self.code)

默认情况下：

schemes = ['http', 'https', 'ftp', 'ftps']

所以很明显，只允许绝对URL

---

另请参见。

这是因为您使用的是url表单字段……如果您希望在不使用http://的情况下传递url，则可以使用普通的字符表单字段

URL字段后面是一个验证，当您想要使用URL字段时，可以更改该验证

---

希望这对您有所帮助，因为您使用的是url表单字段……如果您希望在不使用http://的情况下传递url，那么您可以使用普通的字符表单字段

URL字段后面是一个验证，当您想要使用URL字段时，可以更改该验证

---

希望这能有所帮助

感谢您的回复Se shuttle87-那么您是否建议此url验证代码不起任何作用？我不太明白，如果它实际上不起作用，为什么他们会将其包含在教程中。我又来不及了；）-与主题相关：@ch3ka，事实上，我正打算更新你的答案，只是因为与此相关的票证链接，但我看到你删除了它。@shuttle87取消了删除，因为你认为它是相关的。感谢你的回复。shuttle87-那么你是在建议url验证的代码没有任何作用吗？我不太明白他们为什么会这么做如果这样做行不通，请将其包含在教程中。我又迟到了；）-与主题相关：@ch3ka，事实上，我正打算更新你的答案，只是因为这张罚单的链接，但我看到你删除了它。@shuttle87取消了删除，因为你认为它是相关的。好吧，这就是我要做的来解决这个问题-谢谢！好吧，这就是我要做的来解决这个问题-谢谢！