在本地化页面中删除缓存的问题
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【中文标题】在本地化页面中删除缓存的问题【英文标题】：Problem with deleting cache in localized page 【发布时间】：2021-09-04 11:44:38 【问题描述】：我有页面可以查看帖子。此外，我还有带有切换语言选项的标题，当我切换语言时，它会在所有页面上更改，但具有缓存的页面除外。只有当我重新启动服务器时，语言才会发生变化。当我更改语言时，我需要了解如何删除缓存。 视图.py：
class DetailPostView(generic.DetailView):
def get(self, request, *args, **kwargs):
pk = kwargs['pk']
post = Post.objects.get(pk=pk)
comments = Comment.objects.filter(post=post)
form = CommentForm()
context =
"post": post,
'comments': comments,
'form': form,
return render(request, "detail_post.html", context)
def post(self, request, pk):
post = Post.objects.get(pk=pk)
comments = Comment.objects.filter(post=post)
form = CommentForm(request.POST)
if form.is_valid():
author = self.check_user_authenticated(request, form)
comment = Comment(
author=author,
body=form.cleaned_data['body'],
image=form.cleaned_data['image'] if 'image' in form.cleaned_data else None,
post=post,
user=request.user if isinstance(request.user, User) else None
)
comment.save()
context = 'post': post, 'comments': comments, 'form': form
return render(request, "detail_post.html", context)
def check_user_authenticated(self, request, form):
if request.user.is_authenticated:
author = request.user.profile.name
elif form.cleaned_data['author']:
author = form.cleaned_data['author']
else:
author = 'Anonim'
return author
模型.py：
class Post(models.Model):
title = models.CharField(max_length=25)
body = models.TextField()
image = models.ImageField(blank=True, upload_to=post_directory_path)
created_on = models.DateTimeField(auto_now_add=True)
last_modified = models.DateTimeField(auto_now=True)
categories = models.ManyToManyField('Category', related_name='posts', blank=True)
profile = models.ForeignKey('Profile', verbose_name='User',
on_delete=models.CASCADE,
related_name='profile')
def __str__(self):
return self.title
@receiver(post_save, sender=Post, dispatch_uid="clear_cache_post")
def update_post(sender, **kwargs):
key = make_template_fragment_key('post', [kwargs['instance'].user.id])
cache.delete(key)
模板（detail_post.html）：
% extends "base.html" %
% load i18n %
% load cache %
% block page_content %
<html lang="en">
<head>
<meta charset="UTF-8">
<title>% trans "Detail blog" %</title>
</head>
% cache 500 post request.user.id %
<div class="col-md-8 offset-md-2">
<h1> post.title </h1>
<small>
post.created_on|date:"d.m.Y H:i:s" |
% if post.categories.all %
% trans 'Categories' % :
% for category in post.categories.all %
<a href="% url 'list_category' category.name %"> category.name </a>
% endfor %
% else %
% trans "There isn't any category" %
% endif %
</small>
<p> post.body | linebreaks </p>
% if post.image %
<img src=" MEDIA_URL post.image.url "
>
% endif %
% if request.user.id == post.profile.id %
<form action="/blog/edit/post/ post.id " method="get">
<button class="btn btn-primary" type="submit" data-toggle="collapse"
data-target="#collapseExample"
aria-expanded="false" aria-controls="collapseExample">% trans "Edit post" %
</button>
</form>
% endif %
<h3>% trans "Leave a comment" %: </h3>
<form action="/blog/ post.pk /" method="post">
% csrf_token %
% if not request.user.is_authenticated %
<div class="form-group">
form.author
</div>
% endif %
<div class="form-group">
form.body
</div>
<div class="form-group">
% trans "image" %: form.image
</div>
<button type="submit" class="btn btn-primary">% trans "Submit" %</button>
</form>
% if comments %
<h3>% trans "Comments" %:</h3>
% for comment in comments %
% if comment.user.profile.avatar %
</div>
<img class="col-md-2" src=" MEDIA_URL comment.user.profile.avatar.url "
>
<b> comment.author </b> % trans "wrote at" % comment.created_on|date:"H:i:s d.m.Y"
<div class="col-md-8 offset-md-2">
% else %
<b> comment.author </b> % trans "wrote at" % comment.created_on|date:"H:i:s d.m.Y"
% endif %
<p> comment.body </p>
% if comment.image %
<img src=" MEDIA_URL comment.image.url " >
% endif %
% if request.user.profile %
<form action="/blog/edit/comment/ comment.id " method="get">
<button class="btn btn-primary" type="submit" data-toggle="collapse"
data-target="#collapseExample"
aria-expanded="false" aria-controls="collapseExample">% trans "Edit commentary" %
</button>
</form>
% endif %
<hr>
% endfor %
% else %
<h3>% trans "There isn't any comment yet" %</h3>
% endif %
</div>
% endcache %
% endblock %
模板（base.html）：
% load i18n %
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css"
integrity="sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" crossorigin="anonymous">
<nav class="navbar navbar-expand-lg navbar-light bg-light">
<div class="container">
<a class="navbar-brand" href="https://github.com/Gleb-bit/">% trans 'GitHub' %</a>
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent"
aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarSupportedContent">
<ul class="navbar-nav mr-auto">
<li class="nav-item active">
<a class="nav-link" href="% url 'list_project' %">% trans 'Home' %</a>
</li>
<li class="nav-item">
<a class="nav-link" href="% url 'list_post' %">% trans 'Blog' %</a>
</li>
</ul>
<ul class="navbar-nav nav-tabs">
<li class="nav-item mt-2">
<form action="% url 'set_language' %" method="post">
% csrf_token %
<input name="text" type="hidden" value=" redirect_to ">
<select name="language">
% get_current_language as LANGUAGE_CODE %
% get_available_languages as LANGUAGES %
% get_language_info_list for LANGUAGES as languages %
% for language in languages %
<option value=" language.code " % if language.code == LANGUAGE_CODE %
selected % endif %>
language.name_local ( language.code )
</option>
% endfor %
</select>
<button class="btn-primary" type="submit">% trans 'Go' %</button>
</form>
</li>
<li class="nav-item dropdown">
<a class="nav-link dropdown-toggle" data-toggle="dropdown" role="button" aria-haspopup="true"
aria-expanded="false" href="#">% trans 'More' %</a>
<div class="dropdown-menu">
% if request.user.is_authenticated %
<a class="dropdown-item"
href="/blog/user/ request.user.id ">% trans 'Detail account' %</a>
<a class="dropdown-item" href="% url 'logout' %">% trans 'Logout' %</a>
% else %
<a class="dropdown-item" href="% url 'login' %">% trans 'Login' %</a>
% endif %
</div>
</li>
</ul>
</div>
</div>
</nav>
<div class="container">
% block page_content %% endblock %
</div>
<script src="https://code.jquery.com/jquery-3.3.1.slim.min.js"
integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo"
crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js"
integrity="sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49"
crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js"
integrity="sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy"
crossorigin="anonymous"></script>
语言转换表格：
<form action="% url 'set_language' %" method="post">
% csrf_token %
<input name="text" type="hidden" value=" redirect_to ">
<select name="language">
% get_current_language as LANGUAGE_CODE %
% get_available_languages as LANGUAGES %
% get_language_info_list for LANGUAGES as languages %
% for language in languages %
<option value=" language.code " % if language.code == LANGUAGE_CODE %
selected % endif %>
language.name_local ( language.code )
</option>
% endfor %
</select>
<button class="btn-primary" type="submit">% trans 'Go' %</button>
</form>
【问题讨论】：
你能展示一下你是如何设置语言的吗？ 添加了用于更改相关语言的表单 【参考方案1】：根据Template fragment caching for caches using the cache 模板标签的文档，您可以将当前语言作为参数传递给模板标签，以便它随语言而变化，因此您可以编写以下内容：
% get_current_language as LANGUAGE_CODE %
% cache 500 post request.user.id LANGUAGE_CODE %
<div class="col-md-8 offset-md-2">
...
</div>
% endcache %
对于已缓存的视图，您可以使用文档Using Vary headers 部分中所述的vary_on_headers 装饰器来更改Accept-Language 标头：
from django.views.decorators.cache import cache_page
from django.views.decorators.vary import vary_on_headers
@cache_page(500)
@vary_on_headers('Accept-Language')
def some_view(request):
...
【讨论】：
即我需要这样做：@cache_page(500) @vary_on_headers('Accept-Language') class Detail Post View(generic.DetailView): pass 以及以后如何删除缓存? @Steep27 不，您似乎正在使用cache 模板标签，该视图代码只是一个示例，以防您缓存完整的视图。你需要使用% cache 500 post request.user.id LANGUAGE_CODE %，就像我展示的那样，它会在语言上变化（你不需要删除缓存）。
除了模板中的代码(% cache 500 post request.user.id LANGUAGE_CODE % % for language in languages % % endfor % % endcache %)，我还需要添加什么？
@Steep27 您需要将LANGUAGE_CODE 传递给您使用的所有cache 模板标签，如果您希望它们在语言上有所不同。我认为您没有在表单中使用标签，为什么要在评论中显示它？在示例中，您使用了detail_post.html 中的标签，我在答案中添加了一个截断版本以反映相同的...
或者您是否使用“每站点缓存”，即您已将缓存中间件添加到MIDDLEWARE 设置？以上是关于在本地化页面中删除缓存的问题的主要内容，如果未能解决你的问题，请参考以下文章
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