MTV和MVC模型

Django的MTV模型和四大部分

1. C--urls分发器(路由系统,属于MVC里的C部分),Django内叫做路由系统
2. C--视图系统(业务逻辑,属于MVC里的C部分),Django内叫做视图函数
3. V--模板系统(对用户展示,相当于MVC里的V),Django内叫做templates
4. M--模型(存取数据,在业务逻辑和数据库之间充当桥梁),Django内叫做models

Django模板系统

模板语言符号

def template_test(request):
    list_to_template = ["三鹅", "四筒", '伍德']
    dict_to_template = {"1st": "三鹅",
                        "2nd": "四筒",
                        "3rd": "伍德"}
    
    class Person:
        def __init__(self,name,age):
            self.name = name
            self.age= age
            
        def __str__(self):
            return "".format(self.name,self.age)
            
        def show_age(self):    
            return self.age
    return render(request, 'test.html', {"list": list_to_template,
                                         "dict": dict_to_template,
                                         "jenny": jenny,
                                         })

<p>{{ list }}</p>
<p>{{ list.0 }} {{ list.1 }}</p>
<p>{{ dict.2nd }} {{ dict.3rd }}</p>
<hr>
<p>{{ jenny }}</p>
<p>{{ jenny.show_age }}</p>

['三鹅', '四筒', '伍德']
三鹅 四筒
四筒 伍德
-----------------------------------------
<Person name:jenny, age:18>
18

• 列表可以通过0,1等索引来取得对应位置的值
• 字典通过键取值,采用字典.键名的方法,并不是使用方括号
• 虽然2nd这种不符合python的标识符属性,但可以写在模板里
• 如果传入一个对象,会用其__str__方法的结果去替换字符串
• 对于对象的方法,调用的时候不加括号.Django默认只能支持不带参数的方法,如果带参数,则需要自行编写扩展

内建模板语言语句

filter类

 {{ 变量名|filter_name:参数 }}

自定义filter

# 开头两行是固定的,导入模板,生成一个注册器,用于自己的filter注册在模板内使用.
from django import template
register = template.Library()

# 编写好函数之后,用装饰器,注册一个filter函数名,名字可以不和实际的函数名相同
@register.filter(name="add_s")
def add_suffix(arg, suffix="-Django"):
    return arg + suffix

{% load myfilter %}
{{ value|add_s }}
{{ value|add_s:"-Apache" }}

Mysite-Django
Mysite-Apache

tag关键字

autoescape

{% autoescape on %}
    {{ body }}
{% endautoescape %}

comment

<p>Rendered text with {{ pub_date|date:"c" }}</p>
{% comment "Optional note" %}
    <p>Commented out text with {{ create_date|date:"c" }}</p>
{% endcomment %}

cycle

{% for o in some_list %}
    <tr class="{% cycle 'row1' 'row2' %}">
        ...
    </tr>
{% endfor %}

<tr>
    <td class="{% cycle 'row1' 'row2' as rowcolors %}">...</td>
    <td class="{{ rowcolors }}">...</td>
</tr>
<tr>
    <td class="{% cycle rowcolors %}">...</td>
    <td class="{{ rowcolors }}">...</td>
</tr>

{% for obj in some_list %}
    {% cycle 'row1' 'row2' as rowcolors silent %}
    <tr class="{{ rowcolors }}">{% include "subtemplate.html" %}</tr>
{% endfor %}

csrf_token

firstof

{% firstof var1 var2 var3 "fallback value" %}

{% firstof var1 var2 var3 as value %} 

for

<ul>
{% for athlete in athlete_list %}
    <li>{{ athlete.name }}</li>
{% endfor %}
</ul>

{% for obj in list reversed %}

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

<ul>
{% for athlete in athlete_list %}
    <li>{{ athlete.name }}</li>
{% empty %}
    <li>Sorry, no athletes in this list.</li>
{% endfor %}
</ul>

if

{% if athlete_list %}
    Number of athletes: {{ athlete_list|length }}
{% elif athlete_in_locker_room_list %}
    Athletes should be out of the locker room soon!
{% else %}
    No athletes.
{% endif %}

{% if value|length > 10 %}
    <p>Length is greater than 10</p>
{% else %}
    <p>Length is less than 10</p>
{% endif %}

ifchanged

<h1>Archive for {{ year }}</h1>

{% for date in days %}
    {% ifchanged %}<h3>{{ date|date:"F" }}</h3>{% endifchanged %}
    <a href="{{ date|date:"M/d"|lower }}/">{{ date|date:"j" }}</a>
{% endfor %}

{% for date in days %}
    {% ifchanged date.date %} {{ date.date }} {% endifchanged %}
    {% ifchanged date.hour date.date %}
        {{ date.hour }}
    {% endifchanged %}
{% endfor %}

{% for match in matches %}
    <div style="background-color:
        {% ifchanged match.ballot_id %}
            {% cycle "red" "blue" %}
        {% else %}
            gray
        {% endifchanged %}
    ">{{ match }}</div>
{% endfor %}

load

now

It is {% now "jS F Y H:i" %}

{% now "Y" as current_year %}
{% blocktrans %}Copyright {{ current_year }}{% endblocktrans %}

resetcycle

spaceless

{% spaceless %}
    <p>  <strong> Hello  </strong></p>
{% endspaceless %}

templatetag

{% templatetag openblock %} url 'entry_list' {% templatetag closeblock %}

with

{% with total=business.employees.count %}
    {{ total }} employee{{ total|pluralize }}
{% endwith %}

url

{% url url_name %}

母版及相关tag

extends 与 block

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="x-ua-compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Title</title>
  {% block page-css %}
  
  {% endblock %}
</head>
<body>

<h1>这是母板的标题</h1>

{% block page-main %}

{% endblock %}
<h1>母板底部内容</h1>
{% block page-js %}

{% endblock %}
</body>
</html>

• 通用静态文件引用
• 个性化CSS文件引用
• 导航条
• 侧边栏
• 页面主体部分
• 页脚部分

{% extends 'mother.html' %}

{% block page-css %}
<link rel="stylesheet" href="/static/bootstrap/css/bootstrap.min.css">
{% endblock %}

{% block page-main %}
<p class="text-center">这是页面的主体部分,是从子版替换过来的</p>
{% endblock %}

{% block page-js %}
<p class="text-danger text-center">这是页面的底部</p>
{% endblock %}

<p>这是页面外边的部分</p>

include

<div class="row text-center text-danger"><p>我是从footer.html导入的页脚部分</p></div>

{% block page-js %}
{% include "footer.html" %}
{% endblock %}

静态文件路径变量

{% block page-css %}
{% load static %}
<link rel="stylesheet" href="{% static "bootstrap/css/bootstrap.min.css" %}">
{% endblock %}

{% block page-css %}
{% load static %}
<link rel="stylesheet" href="{% static "bootstrap/css/bootstrap.min.css" as bootstrap %}">
<link rel="stylesheet" href="{{ bootstrap }}">
{% endblock %}

自定义tag函数

自定义simple_tag函数

# mytag.py
from django import template
register = template.Library()

@register.simple_tag(name="mysum")
def my_sum(*args):
    temp = ""
    for arg in args:
        temp += arg
    return temp

{% load mytag %}

{% mysum value1 value2 value3 value4 %}

自定义inclusion_tag函数

# mytag.py
@register.inclusion_tag('result.html')
def show_results(n):
    n = 1 if n < 1 else int(n)
    data = ["第{}项".format(i) for i in range(1, n+1)]
    return {"data": data}

<ul>
  {% for choice in data %}
    <li>{{ choice }}</li>
  {% endfor %}
</ul>

{% load mytag %}
{% mysum value1 value2 value3 value4 %}
{% show_results 10 %}