在包含多个表单字段的 Django 页面中的正确位置显示验证错误

Question

在我搭建的一个 Django 社交网站中，用户可以在普通房间里聊天，或者创建私人群组。

每个用户都有一个主仪表板，他们参与的所有对话都显示在一起，彼此堆叠（按 20 个对象进行分页）。我称之为unseen activity 页面。此页面上的每个看不见的对话都有一个文本框，用户可以直接在其中输入回复。此类回复通过 <form> 内的 POST 请求提交。

每个<form> 的action 属性指向不同的网址，具体取决于提交的回复类型（例如home_comment 或group_reply）。这是因为它们有不同的验证和处理要求等。

问题是这样的：如果引发了 ValidationError（例如，用户输入了带有禁止字符的回复），它会显示在unseen_activity 中的多个表单上页面，而不仅仅是生成它的特定表单。如何确保所有 ValidationErrors 仅出现在它们起源的表单上？一个说明性的例子会很棒！

---

附加到所有这些的表单类称为UnseenActivityForm，并定义如下：

class UnseenActivityForm(forms.Form):
    comment = forms.CharField(max_length=250)
    group_reply = forms.CharField(max_length=500)
    class Meta:
        fields = ("comment", "group_reply", )

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

    def clean_comment(self):
        # perform some validation checks
        return comment

    def clean_group_reply(self):
        # perform some validation checks
        return group_reply

模板如下所示：

{% for unseen_obj in object_list %}

    {% if unseen_obj.type == '1' %}

    {% if form.comment.errors %}{{ form.comment.errors.0 }}{% endif %}
    <form method="POST" action="{% url 'process_comment' pk %}">
    {% csrf_token %}
    {{ form.comment }}
    <button type="submit">Submit</button>
    </form>

    {% if unseen_obj.type == '2' %}

    {% if form.group_reply.errors %}{{ form.group_reply.errors.0 }}{% endif %}
    <form method="POST" action="{% url 'process_group_reply' pk %}">
    {% csrf_token %}
    {{ form.group_reply }}
    <button type="submit">Submit</button>
    </form>

    {% endif %}

{% endfor %}

现在是观点。我不会一次性处理所有内容。一个函数负责为 GET 请求生成内容，其他函数负责处理 POST 数据处理。如下：

def unseen_activity(request, slug=None, *args, **kwargs):
        form = UnseenActivityForm()
        notifications = retrieve_unseen_notifications(request.user.id)
        page_num = request.GET.get('page', '1')
        page_obj = get_page_obj(page_num, notifications, ITEMS_PER_PAGE)
        if page_obj.object_list:
            oblist = retrieve_unseen_activity(page_obj.object_list)
        else:
            oblist = []
        context = {'object_list': oblist, 'form':form, 'page':page_obj,'nickname':request.user.username}
        return render(request, 'user_unseen_activity.html', context)

def unseen_reply(request, pk=None, *args, **kwargs):
        if request.method == 'POST':
            form = UnseenActivityForm(request.POST,request=request)
            if form.is_valid():
                # process cleaned data
            else:
                notifications = retrieve_unseen_notifications(request.user.id)
                page_num = request.GET.get('page', '1')
                page_obj = get_page_obj(page_num, notifications, ITEMS_PER_PAGE)
                if page_obj.object_list:
                    oblist = retrieve_unseen_activity(page_obj.object_list)
                else:
                    oblist = []
                context = {'object_list': oblist, 'form':form, 'page':page_obj,'nickname':request.user.username}
                return render(request, 'user_unseen_activity.html', context)

def unseen_group_reply(group_reply, pk=None, *args, **kwargs):
            #similar processing as unseen_reply

注意：代码是我实际代码的简化版本。如果需要，请询问更多详细信息。

Answer 1

根据上述 cmets 中的讨论：

我的建议是为视图中的每个实例创建一个表单。我已经重构了您的代码，使其具有返回对象列表的函数，您可以在 unseen_reply 和 group_reply 函数中使用它：

def get_object_list_and_forms(request):
    notifications = retrieve_unseen_notifications(request.user.id)
    page_num = request.GET.get('page', '1')
    page_obj = get_page_obj(page_num, notifications, ITEMS_PER_PAGE)
    if page_obj.object_list:
        oblist = retrieve_unseen_activity(page_obj.object_list)
    else:
        oblist = []

    # here create a forms dict which holds form for each object 
    forms = {}
    for obj in oblist:
        forms[obj.pk] = UnseenActivityForm()

    return page_obj, oblist, forms


def unseen_activity(request, slug=None, *args, **kwargs):
    page_obj, oblist, forms = get_object_list_and_forms(request)

    context = {
        'object_list': oblist,
        'forms':forms,
        'page':page_obj,
        'nickname':request.user.username
    }
    return render(request, 'user_unseen_activity.html', context)

现在，您需要使用对象 ID from forms dict 访问模板中的表单。

{% for unseen_obj in object_list %}
    <!-- use the template tag in the linked post to get the form using obj pk -->
    {% with forms|get_item:unseen_obj.pk as form %}
        {% if unseen_obj.type == '1' %}

            {% if form.comment.errors %}{{ form.comment.errors.0 }}{% endif %}
            <form method="POST" action="{% url 'process_comment' pk %}">
                {% csrf_token %}
                {{ form.comment }}
                <button type="submit">Submit</button>
            </form>

        {% elif unseen_obj.type == '2' %}

            {% if form.group_reply.errors %}{{ form.group_reply.errors.0 }}{% endif %}
            <form method="POST" action="{% url 'process_group_reply' pk %}">
                {% csrf_token %}
                {{ form.group_reply }}
                <button type="submit">Submit</button>
            </form>

        {% endif %}
    {% endwith %}
{% endfor %}

在处理回复时，您再次需要附加与特定对象 pk 引发错误的表单：

def unseen_reply(request, pk=None, *args, **kwargs):
    if request.method == 'POST':
        form = UnseenActivityForm(request.POST,request=request)
        if form.is_valid():
        # process cleaned data
        else:
            page_obj, oblist, forms = get_object_list_and_forms(request)

            # explicitly set the form which threw error for this pk
            forms[pk] = form

            context = {
                'object_list': oblist,
                'forms':forms,
                'page':page_obj,
                'nickname':request.user.username
            }
            return render(request, 'user_unseen_activity.html', context)