Django 开发模板与视图

Django最强大的部分之一是自动管理界面。它从模型中读取元数据，以提供一个快速的，以模型为中心的界面，受信任的用户可以在其中管理您网站上的内容。管理员的建议用法仅限于组织的内部管理工具。它并非旨在构建您的整个前端。

初始化Django

pip install django                                  # 安装
django-admin startproject MyProject                 # 创建项目
D:MyProject> django-admin startapp MyWeb            # 创建APP
D:MyProject> python manage.py runserver 0.0.0.0:80  # 启动Django

D:MyProject> python manage.py shell   # 进入Django交互shell
D:MyProject> python manage.py dbshell # 进入DBShell
D:MyProject> python manage.py check   # 检查Django完整性

修改一下django的配置文件settings.py,导入我们生成APP的名字.

MIDDLEWARE = [
    'django.middleware.security.SecurityMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.common.CommonMiddleware',
    #'django.middleware.csrf.CsrfViewMiddleware',                # 注释掉此行
    'django.contrib.auth.middleware.AuthenticationMiddleware',
]
INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'MyWeb.apps.MywebConfig'           # 添加此行,导入我们的APP的名字
]

然会修改urls.py在这里写一条路由记录.

from MyWeb import views

urlpatterns = [
    path('admin/', admin.site.urls),
    path("hello/",views.hello,name="hello")
]

最后我们在views.py视图函数里添加一条路由.

from django.shortcuts import HttpResponse

def hello(request):
    return HttpResponse("<h1>hello lyshark</h1>")

有时候我们需要在本地引入JS或者静态资源,此时你需要修改一下Django的setting.py里面的路径.

# Static files (CSS, JavaScript, Images)
# https://docs.djangoproject.com/en/3.0/howto/static-files/
# 此时我们的默认路径是/static/,那么前端就可以直接调用<script src="/static/lyshark.js">
STATIC_URL = '/static/'
STATICFILES_DIRS=(
    os.path.join(BASE_DIR,'static')
)

邮件发送

# name:settings.py
STATIC_URL = '/static/'
EMAIL_USER_TLS = True
EMAIL_PORT = 25
EMAIL_HOST = "smtp.163.com"
EMAIL_HOST_USER = "smtpwho@163.com"
EMAIL_HOST_PASSWORD = "授权密码"

# name: views.py
from django.shortcuts import render,HttpResponse
from django.core.mail import send_mail, send_mass_mail, EmailMultiAlternatives

def send(request):
    if request.method == "GET":
        return HttpResponse("""
        <form action="/send/" method="POST">
            <input type="submit" value="发送邮件">
        </form>
        """)
    else:
        ret = send_mail("Django 邮件通知",                # 邮件名称
                        "这是一封来自Django的邮件",        # 邮件内容
                        "smtpwho@163.com",               # 发信邮箱
                        ['admin@blib.cn'])               # 收信邮箱
        if ret:
            return HttpResponse("完成")
        else:
            return HttpResponse("失败")

使用类视图映射

# name:urls.py
from MyWeb import views
urlpatterns = [
    path('index/',views.index.as_view())
]

# name:views.py
from django import views
class index(views.View):
    def get(self,request,*args,**kwargs):
        pass

    def post(self,request,*args,**kwargs):
        pass

简单的路由编写

urlpatterns = [
    path('admin/', admin.site.urls),
    path('',views.index,name="index"),                                     # 一条访问主站的路由
    path('login/id=<int:id>&name=<str:name>',views.login,name="login"),    # 名称后面传递参数
    path('add/<int:x>/<int:y>/',views.add,name="add")                      # 路径中传递参数
]

from django.shortcuts import render,HttpResponse
def index(request):
    return render(request,"index.html")

def login(request, id, name):
    return HttpResponse("用户ID{} , 用户名{} ".format(id,name))

def add(request,x,y):
    temp = int(x)+int(y)
    return HttpResponse("相加结果:{}".format(temp))

使用模板传递简单的参数

<b>用户名: {{ user }} 密码:{{ pasd }} 标题:{{ title }}</b>

def index(request):
    username = "lyshark"
    password = "123123"
    title = "hello lyshark"
    return render(request,"index.html",{"user":username,"pasd":password,"title":title})

后端组装数据然后传递给前端

<b>用户名: {{ user }} 密码:{{ pasd }} 标题:{{ title }}</b>

def index(request):
    username = "admin"
    password = "123123"
    title = "hello lyshark"

    dict = {
        "user": username,
        "pasd": password,
        "title": title
    }
    return render(request,"index.html",dict)

通过info变量遍历出指定字段元素

<b>站点名称:{{ info.site }} 站点描述:{{ info.content }}</b>

def index(request):
    info = {"site":"blib.cn","content":"hello lyshark"}
    return render(request,"index.html",{"info":info})

通过for语句遍历打印列表数据

    {% for item in total %}
        <b>打印数据: {{ item }}</b><br>
    {% endfor %}

def index(request):
    lists = ["HTML","CSS","JAVASCRIPT","Python","JQuery"]
    return render(request,"index.html",{"total":lists})

通过for语句倒序循环打印

    {% for item in total reversed%}
        <b>打印数据: {{ item }}</b><br>
    {% endfor %}

def index(request):
    lists = ["1","2","3","4","5"]
    return render(request,"index.html",{"total":lists})

通过使用for循环遍历字典

{% for key,value in info.items %}
    {{ key }} : {{ value }}
{% endfor %}

def index(request):
    info = {"site":"blib.cn","content":"hello lyshark"}
    info1 = {"site": "blib.cn", "content": "hello admin"}

    return render(request,"index.html",{"info":info,"info1":info1})

Django 实现选择框选择

<form action="/index/" method="post">
    选择A:
    <select name="tag_select_a">
        {% for item in total_a %}
            <option value = "{{ item }}"> {{ item }} </option>
        {% endfor %}
    </select>
    选择B:
    <select name="tag_select_b">
        {% for item in total_b %}
            <option value = "{{ item }}"> {{ item }} </option>
        {% endfor %}
    </select>
    <input type="submit" value="提交选择">
</form>


def index(request):
    if request.method == "GET":
        tag_select_a = ["HTML", "CSS", "JAVASCRIPT", "Python", "JQuery"]
        tag_select_b = ["MySQL","Oracle","MSSQL"]
        return render(request, "index.html", {"total_a": tag_select_a,"total_b": tag_select_b})
    elif request.method == "POST":
        select_a = request.POST.get("tag_select_a")
        select_b = request.POST.get("tag_select_b")
        return HttpResponse("选择A: {} 选择B: {}".format(select_a,select_b))

简单的路径拼接

<a href="{{ request.path }}?uid=1">当前网址加参数</a>

<!--获取当前路径      拼接成 /add/4/5-->
{{ request.path }}{% url 'add' 4 5 %}

def add(request,x,y):
    temp = int(x)+int(y)
    return HttpResponse("相加结果:{}".format(temp))

def index(request):
    return render(request,"index.html")

判断用户是否登录

{% if request.user.is_authenticated %}
    {{ request.user.username }}，您好！
{% else %}
    请登陆，这里放登陆链接
{% endif %}

使用if语句判断数据

{% if username == "lyshark" and password == "123123" %}
    <b>恭喜你</b>
{% elif username == "admin" or password == "123123" %}
    <b>欢迎管理员</b>
{% else %}
    <b>这个都不是</b>
{% endif %}

def index(request):
    username = "admin"
    password = "123123"
    return render(request,"index.html",{"username":username,"password":password})

if语句也可以判断列表元素

{% if 1 in list %}
    <b>在里面</b>
{% elif 10 not in list %}
    <b> 不在里面</b>
{% endif %}

def index(request):
    list = [1,2,3,4,5]
    return render(request,"index.html",{"list":list})

最后的大总结:if与for语句的结合

{% for item in info %}
    {% if forloop.first %}
        <b>开始了</b>
    {% endif %}
    {{ forloop.counter }} : {{ item }}<br>
    {% if forloop.last %}
        <b>最后了</b>
    {% endif %}
{% endfor %}

def index(request):
    list = map(str,range(100))
    return render(request,"index.html",{"info":list})

forloop.counter 索引从 1 开始算
forloop.counter0    索引从 0 开始算
forloop.revcounter  索引从最大长度到 1
forloop.revcounter0 索引从最大长度到 0
forloop.first   当遍历的元素为第一项时为真
forloop.last    当遍历的元素为最后一项时为真
forloop.parentloop  
用在嵌套的 for 循环中，获取上一层 for 循环的 forloop

常用的过滤器: 常用的过滤器,有以下几种.

    <b> 列表长度: {{ total | length }}</b><br>
    <b> 输出大小: {{ size | filesizeformat }}</b><br>
    <b> 输出时间: {{ date | date:"Y-m-d" }}</b><br>
    <b> 首字母大写: {{ title | capfirst }}</b><br>
    <b> 从字符串中移除hello字符: {{title | cut:"hello" }}</b><br>
    <b> 显示字符串第一个元素: {{ total | first }}</b><br>
    <b> 显示字符串最后一个元素: {{ total | last }}</b><br>
    <b> 大小写转换(upper/lower): {{ title | upper }}</b><br>
    <b> 对数据切片: {{ title | slice:"2:-1" }}</b><br>
    <b>截断字符：{{ title | truncatechars:5 }}</b><br>
    <b>截断单词：{{ title | truncatewords:1 }}</b>

def index(request):
    filesize = 10240
    title = "hello lyshark"
    date = datetime.datetime.now()
    lists = ["1","2","3","4","5"]
    return render(request,"index.html",{"total":lists,"size":filesize,"date":date,"title":title})

自定义过滤器与标签

1.首先在Django项目下的APP里面,创建一个templatetags的目录,这个目录名不能变.

MyWeb/
    __init__.py
    models.py
    templatetags/
        __init__.py
        mysimple.py
    views.py

2.在templatetags目录下创建任意的py文件,此处我们就创建一个mysimple.py,并写入以下两条内容.

from django import template
from django.utils.safestring import mark_safe

register = template.Library() # 此处必须这样写

# simple_tag（自定义标签）：不会限制传参,但不支持if
@register.simple_tag
def simple_time(var1,var2,var3):
    temp = int(var1)+int(var2)+int(var3)
    return temp

# filter（自定义过滤器）：限制传参2个,但支持if
@register.filter
def My_filter(value, arg):
    # 传递一个参数的过滤器
    return str.upper(value) + arg

3.在我们需要使用自定义过滤器的时候,必须在index.html中引入这个变量,然后在前端就可以调用了.

# name: views.py
def index(request):
    title = "hello"
    return render(request,"index.html",{"title":title})

# name: index.html
<!--引入自定义的过滤器-->
{% load mysimple %}

<b>自定义标签返回数值: {% simple_time 10 20 30 %}</b>          <!-- 传递多个参数 -->
<b>传递一个参数的过滤器: {{ title | My_filter:'lyshark' }}</b> <!-- 传递一个参数 -->

模板与模板继承

母板：             {% block title %}{% endblock %}
子板继承：         {% extends "base.html" %}
子板中使用其他模板: {% include "xx.html" %}
设置标题:          {% block title %}{% endblock %}
使用CSS资源:       {% block css %} {% endblock %}
使用JS资源:        {% block js %} {% endblock %}

1.首先创建一个base.html文件,以作为我们的母版.

<html>
<head>
    <meta charset="UTF-8">
    {% block css %}{% endblock %}
</head>
    <body>
        <div class="pg-body">
            <div class="body-menu">
                <ul>
                    <li><a href="/user">用户管理</a></li>
                    <li><a href="/hosts">资产管理</a></li>
                </ul>
            </div>
            <div class="body-content">
                {% block body %}{% endblock %}   <!--占位符,用于填充子版块-->
            </div>
        </div>
        {% block js %}{% endblock %}
    </body>
</html>

接着我们需要创建一个子板并继承母版,此处我们创建一个hosts.html这样的文件.

{% extends 'base.html' %}
{% block js %} {% endblock %}
{% block css %} {% endblock %}

{% block body %}
    <table>
        {% for item in host %}
            <tr>
                <td>{{ item.hostname }}</td>
                <td>{{ item.port }}</td>
            </tr>
        {% endfor %}
    </table>
{% endblock %}

我们继续创建一个user.html,同样也是继承base.html模板.

{% extends 'base.html' %}

{% block js %} {% endblock %}
{% block css %} {% endblock %}

{% block body %}
    <ul>
    {% for item in user_list %}
        <li>{{ item.username }},{{ item.salary }}</li>
    {% endfor %}
    </ul>
{% endblock %}

此处我们需要在urls.py里面写好路由分发.

from django.contrib import admin
from django.urls import path
from MyWeb import views

urlpatterns = [
    path('admin/', admin.site.urls),
    path('',views.index,name="index"),
    path('hosts/',views.hosts,name="hosts"),
    path('user/',views.userinfo,name="user")
]

然后写好views.py中的视图函数,默认我们返回base.html这个页面.

from django.shortcuts import render
from django.shortcuts import HttpResponse

def index(request):
    return render(request,"base.html")

def hosts(request):
    hosts_list = []
    for i in range(10):
        temp = {'hostname':'192.168.1.'+str(i),'port':80}
        hosts_list.append(temp)
    return render(request,'hosts.html',{'host':hosts_list})

def userinfo(request):
    user_list = []
    for i in range(10):
        temp = {'username': 'user' + str(i),'salary':80}
        user_list.append(temp)
    return render(request,'user.html',{'user_list':user_list})