Django学习：上下篇博客和按日期分类(13)

在具体每一篇博客中添加上一篇博客，下一篇博客将对用户更加友好。另外可以添加一个按月的分类。

添加上一篇博客，可以找到当前博客创建日期之前的所有博客，选择最后一个。添加下一篇博客，可以找到当前博客创建日期之后的所有博客，选择第一个。这个过程中需要使用filter的一些筛选条件。

大于：__gt
大于等于:__gte
小于:__lt
小于等于:__lte
包含:__contains  __icontains(忽略大小写)
以xx开头:__startswith
以xx结尾:__endswith
其中之一:__in
范围:__range

• 修改views.py文件的blog_detail()函数

def blog_detail(request,blog_pk):
    context = {}
    blog = get_object_or_404(Blog, pk=blog_pk)
    context['previous_blog'] = Blog.objects.filter(created_time__gt=blog.created_time).last()
    context['next_blog'] = Blog.objects.filter(created_time__lt=blog.created_time).first()
    context['blog'] = blog
    return render_to_response('blog/blog_detail.html', context)

• 修改blog_detail.html模板页面

{% extends 'base.html' %}
{% block title %}{{ blog.title }}{% endblock %}
{% block nav_blog_active %}active{% endblock %}
{% load staticfiles %}

{% block header_extends %}
	<link rel="stylesheet" type="text/css" href="{% static 'blog/blog.css' %}">
{% endblock %}

{# 页面内容 #}
{% block content %}
	<div class="container">
		<div class="row">
			<div class='col-xs-10 col-xs-offset-1'>
				<h3>{{ blog.title }}</h3>
					<ul class='blog_info_description'>
						<li>作者：{{ blog.author }}</li>
						<li>分类：<a href='{% url "blogs_with_type" blog.blog_type.pk %}'>{{ blog.blog_type }}</a></li>
						<li>发表时间：{{ blog.created_time|date:"Y-m-d G:m:s" }}</li>
					</ul>
					<div class='blog-content'>{{ blog.content }}</div>
					<div class="blog-more">
						<p>上一篇：
							{% if previous_blog %}
								<a href="{% url 'blog_detail' previous_blog.pk %}">{{ previous_blog.title }}</a>
							{% else %}
								没有了
							{% endif %}
						</p>
						<p>下一篇：
							{% if next_blog %}
								<a href="{% url 'blog_detail' next_blog.pk %}">{{ next_blog.title }}</a>
							{% else %}
								没有了
							{% endif %}
						</p>
					</div>
			</div>
		</div>
	</div>
	
{% endblock %}

通过blog.css进行调整

....
div.blog-more {
	margin-top: 1em;
}

现在详情页面显示如下：

---

filter的扩展使用

进入shell模式进行测试

(mysite_env) G:\mysite_env\mysite>python manage.py shell
Python 3.7.4 (tags/v3.7.4:e09359112e, Jul  8 2019, 20:34:20) [MSC v.1916 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>> from blog.models import Blog
>>> Blog.objects.filter(title__contains='长文本')
<QuerySet [<Blog: <Blog: 长文本博客>>]>
>>> Blog.objects.filter(title__icontains='for 3')
<QuerySet [<Blog: <Blog: for 30>>, <Blog: <Blog: for 3>>]>
>>> Blog.objects.filter(id__in=[2,5,8])
<QuerySet [<Blog: <Blog: for 2>>, <Blog: <Blog: 长文本博客>>, <Blog: <Blog: 第二篇博客>>]>
>>> Blog.objects.filter(id__range=(5,11))
<QuerySet [<Blog: <Blog: for 5>>, <Blog: <Blog: for 4>>, <Blog: <Blog: for 3>>, <Blog: <Blog: for 2>>, <Blog: <Blog: for 1>>, <Blog: <Blog: shell模式下第一篇文章>>, <Blog: <Blog: 长文本博客>>]>

如果是想筛选出不包含目标条件的内容的话，不是使用filter,而是使用exclude来进行筛选。

exclude用法与filter一样。

---

添加一个按日期搜索博客的列表，是一个完全的模块，需要建立一个面板，将日期遍历出来，还需要设置路由和处理方法。

• 修改blog urls.py路由文件

from django.urls import path
from . import views

urlpatterns = [
	path('', views.blog_list, name='blog_list'),
    path('<int:blog_pk>', views.blog_detail, name='blog_detail'),
    path('type/<int:blog_type_pk>', views.blogs_with_type, name='blogs_with_type'),
    path('date/<int:year>/<int:month>', views.blogs_with_date, name='blogs_with_date')
]

• 修改views.py文件blog_list()函数，增加一个blog_dates

context['blog_dates'] = Blog.objects.dates('created_time', 'month', order='DESC')
# 先不实现
def blogs_with_date(request, year, month):
    pass

• 修改blog_list.html文件，增加日期时间的面板

.....
<div class='hidden-xs col_sm_4 col-md-3 col_lg_2'>
				<div class="panel panel-default">
					 <div class="panel-heading">博客分类</div>
					 <div class="panel-body">
					    <ul class='blog_types'>
							{% for blog_type in blog_types %}
							<li><a href='{% url "blogs_with_type" blog_type.pk %}'>{{ blog_type.type_name }}</a></li>
							{% empty %}
							<li>暂无分类</li>
							{% endfor %}
						</ul>
					</div>
				</div>
				<div class="panel panel-default">
					<div class="panel-heading">日期归档</div>
					<div class="panel-body">
						<ul>
							{% for blog_date in blog_dates %}
								<li>{{ blog_date|date:"Y年m月" }}</li>
							{% endfor %}
						</ul>
					</div>
				</div>
			</div>

设置全局base.css，去除列表前面的点

* {
	margin: 0;
	padding: 0;
}
body {
	margin-top: 70px!important;
}
ul {
	list-style-type: none;
}

强制刷新博客列表页

给日期面板增加超链接

blog_list.html

....
<div class="panel panel-default">
					<div class="panel-heading">日期归档</div>
					<div class="panel-body">
						<ul>
							{% for blog_date in blog_dates %}
								<li>
									<a href="{% url 'blogs_with_date' blog_date.year blog_date.month %}">{{ blog_date|date:"Y年m月" }}</a>
								</li>
							{% endfor %}
						</ul>
					</div>
				</div>

此时点击链接会报错，因为处理方法还没有写。

• 修改views.py文件

def blogs_with_date(request, year, month):
    context = {}
    blogs_all_list = Blog.objects.filter(created_time__year=year, created_time__month=month)
    paginator = Paginator(blogs_all_list, settings.EACH_PAGE_BLOGS_NUMBER)
    page_num = request.GET.get('page', 1) # 获取url的页面参数（GET请求）
    page_of_blogs = paginator.get_page(page_num)
    current_page_num = page_of_blogs.number # 获取当前页码
    # 获取当前页前后各2页
    page_range = list(range(max(current_page_num - 2, 1), current_page_num)) + list(range(current_page_num, min(current_page_num + 2, paginator.num_pages) + 1))
    
    # 加上省略号
    if page_range[0] - 1 >= 2:
        page_range.insert(0, '...')
    if paginator.num_pages - page_range[-1] >= 2:
        page_range.append('...')

    # 加上首尾页码
    if page_range[0] != 1:
        page_range.insert(0, 1)
    if page_range[-1] != paginator.num_pages:
        page_range.append(paginator.num_pages)

    context = {}
    context['blogs_with_date'] = '%s年%s月' % (year, month)
    context['blogs'] = page_of_blogs.object_list
    context['page_range'] = page_range
    context['page_of_blogs'] = page_of_blogs
    context['blog_types'] = BlogType.objects.all()
    context['blog_dates'] = Blog.objects.dates('created_time', 'month', order='DESC')
    return render_to_response('blog/blogs_with_date.html', context)

• 在blog templates blog下面建立blogs_with_date.html模板文件

{% extends 'blog/blog_list.html' %}
{# 页面标题 #}
{% block title %}{{ blog_type.type_name }}{% endblock %}
{% block blog_list_title %}
	日期归档：{{ blogs_with_date }}
	<a href='{% url "blog_list" %}'>查看全部博客</a>
{% endblock %}

此时可以从日期归档进入到相应博客列表界面。

---

目前views.py文件中的代码存在大量的重复，需要进行优化。

• 修改views.py

from django.shortcuts import render_to_response,get_object_or_404
from django.core.paginator import Paginator
from django.conf import settings
from .models import Blog, BlogType

# Create your views here.

def get_blog_list_comment_data(request, blogs_all_list):
    paginator = Paginator(blogs_all_list, settings.EACH_PAGE_BLOGS_NUMBER) 
    page_num = request.GET.get('page', 1) # 获取url的页面参数（GET请求）
    page_of_blogs = paginator.get_page(page_num)
    current_page_num = page_of_blogs.number # 获取当前页码
    # 获取当前页前后各2页
    page_range = list(range(max(current_page_num - 2, 1), current_page_num)) + list(range(current_page_num, min(current_page_num + 2, paginator.num_pages) + 1))
    
    # 加上省略号
    if page_range[0] - 1 >= 2:
        page_range.insert(0, '...')
    if paginator.num_pages - page_range[-1] >= 2:
        page_range.append('...')

    # 加上首尾页码
    if page_range[0] != 1:
        page_range.insert(0, 1)
    if page_range[-1] != paginator.num_pages:
        page_range.append(paginator.num_pages)

    context = {}
    context['blogs'] = page_of_blogs.object_list
    context['page_range'] = page_range
    context['page_of_blogs'] = page_of_blogs
    context['blog_types'] = BlogType.objects.all()
    context['blog_dates'] = Blog.objects.dates('created_time', 'month', order='DESC')
    return context

def blog_list(request):
    blogs_all_list = Blog.objects.all()
    context = get_blog_list_comment_data(request, blogs_all_list)
    return render_to_response('blog/blog_list.html', context)

def blogs_with_type(request, blog_type_pk):
    blog_type = get_object_or_404(BlogType, pk=blog_type_pk)
    blogs_all_list = Blog.objects.filter(blog_type=blog_type)
    context = get_blog_list_comment_data(request, blogs_all_list)
    context['blog_type'] = blog_type
    return render_to_response('blog/blogs_with_type.html', context)

def blogs_with_date(request, year, month):
    blogs_all_list = Blog.objects.filter(created_time__year=year, created_time__month=month)
    context = get_blog_list_comment_data(request, blogs_all_list)
    context['blogs_with_date'] = '%s年%s月' % (year, month)
    return render_to_response('blog/blogs_with_date.html', context)

def blog_detail(request,blog_pk):
    context = {}
    blog = get_object_or_404(Blog, pk=blog_pk)
    context['previous_blog'] = Blog.objects.filter(created_time__gt=blog.created_time).last()
    context['next_blog'] = Blog.objects.filter(created_time__lt=blog.created_time).first()
    context['blog'] = blog
    return render_to_response('blog/blog_detail.html', context)

刷新页面查看