Django模型在文章修改时自动更新用户名和日期/时间

Question

我有一个名为 Post 的模型，我正在尝试自动保存上次修改文章的登录用户的用户名以及时间戳。到目前为止 DateTime 时间戳正在更新值，但我无法使用用户名获得相同的结果。

models.py

class Post(models.Model):
    article = models.TextField(max_length=2000)
    username = models.ForeignKey(User, on_delete=models.CASCADE, related_name='usernames')
    updated_at = models.DateTimeField(auto_now=True)

forms.py

class PostForm(ModelForm):

    def __init__(self, *args, **kwargs):    

        super(PostForm, self).__init__(*args, **kwargs)
        
    class Meta:
        model = Post
        fields = '__all__'

views.py

class PostUpdate(UpdateView):
    model = Post
    form_class = PostForm
    
    def save_model(self, request, obj, form, change):
        obj.username = request.user
        obj.save()

Answer 1

首先，如果您希望您的用户名仅由 request.user 设置，然后将 editable=False 添加到 Post 模型中的用户名字段。

username = models.ForeignKey(User, on_delete=models.CASCADE, related_name='usernames', editable=False)

然后在您的 admin.py 中：

from . import models
from django.contrib import admin

class PostAdmin(admin.ModelAdmin):
    def save_model(self, request, obj, form, change):
        obj.username = request.user
        obj.save()

admin.site.register(models.Post, PostAdmin)

编辑从这里开始

models.py

from django.db import models
from django import forms

class Post(models.Model):
    article = models.TextField(max_length=2000)
    username = models.ForeignKey(User, on_delete=models.CASCADE, related_name='usernames') # we don't need editable=False anymore
    updated_at = models.DateTimeField(auto_now=True)


class PostForm(forms.ModelForm):
    class Meta:
        model = Post
        fields = '__all__'

views.py

from . import models
from django.shortcuts import render, get_object_or_404
from django.contrib import messages

def post(request, id):
    post = get_object_or_404(models.Post, id=id) # get a specific post with id
    if request.method == 'POST':
        form = models.PostForm(request.POST, instance=post) # create a post form instance
        if form.is_valid():
            data = models.Post() # create a post model instance
            data.article = form.cleaned_data['article']
            data.username = request.user
            # updated_at field updating automatically
            data.save() # dont't forget to save these data
            messages.success(request, 'Article updated successfully') # this line is optional
        else:
            messages.success(request, form.errors) # this line is optional
    else:
       form = models.PostForm(instance=post)
    return render(request, 'post.html', {'form': form})

        

urls.py

from django.urls import path
from . import views

app_name = 'post'
urlpatterns = [
    path('post/<int:id>', views.post, name='article'),
]

html（模板） 没有小部件调整（简单形式）

<form method="POST">
    {% csrf_token %}
    {{ form.as_p }}
    <button type="submit">Send</button>
</form> 

html（模板） 带有小部件调整和引导类（可选）

{% load widget_tweaks %}

<form method="POST">
    {% csrf_token %}
    {% for field in form %}
    <div class="form-group">
        <div class="form-control-border"></div>
        {{ field.label }}
        {% render_field field class="form-control" %}
    </div>
    {% endfor %}
    <button type="submit" class="btn btn-outline-primary-2">Send</button>
</form> 

如果有错误请告诉我

Answer 2

CreateView 或 UpdateView 没有 save_model 方法。为此，您使用 form_valid 方法：

class PostUpdate(UpdateView):
    model = Post
    form_class = PostForm
    
    def form_valid(self, form):
        form.instance.username = self.request.user
        return super().form_valid(form)

你可以在一个mixin中定义逻辑，然后在多个视图中使用这个mixin，例如：

from django.contrib.auth.mixins import LoginRequiredMixin

class PostAutorMixin(LoginRequiredMixin):
    def form_valid(self, form):
        form.instance.username = self.request.user
        return super().form_valid(form)

然后将其用于：

class PostCreate(PostAuthorMixin, CreateView):
    # …

class PostUpdate(PostAuthorMixin, UpdateView):
    # …

在PostCreate 和PostUpdate 视图中，您不会覆盖form_valid 方法。

---

注意：ForeignKey 确实不存储 列中引用的对象，它存储它的记录的主键 在带有_id 后缀的列中引用ForeignKey 字段。所以 ForeignKeys 通常不以_name 后缀结尾。你可能想要 考虑将 username 字段重命名为 author。

---

注意：您可以将视图限制为基于类的视图，以便通过身份验证的用户使用 LoginRequiredMixin mixin [Django-doc].

Answer 3

你可以使用request.user

# Editing Article View
post_to_be_modified.username = request.user
post_to_be_modified.save()

虽然该字段应称为user 或author，因为它不仅存储用户名，还存储用户。

您不能自动执行此操作，因为用户不是全局 Python 对象，这意味着它必须通过视图参数进行修改。