Building a Python web framework from scratch - Django (2)

Django templates↓

1. Create a new template file hello.html in the templates directory under the project created in the previous article. The directory structure is as follows:

   HelloWorld/
   |-- HelloWorld
   |-- manage.py
   `-- templates
       `-- hello.html

    
2. The hello.html code is as follows:

   {{hello}}

    
3. Modify HelloWorld/settings.py and modify DIRS in TEMPLATES:

   TEMPLATES = [
       {
           'BACKEND': 'django.template.backends.django.DjangoTemplates',
           'DIRS': [BASE_DIR+"/templates"],
           'APP_DIRS': True,
           'OPTIONS': {
               'context_processors': [
                   'django.template.context_processors.debug',
                   'django.template.context_processors.request',
                   'django.contrib.auth.context_processors.auth',
                   'django.contrib.messages.context_processors.messages',
               ],
           },
       },
   ]

    
4. Modify view.py, create a new method, and bind the dictionary to the template

   # -*- coding: utf-8 -*-
    
   #from django.http import HttpResponse
   from django.shortcuts import render
    
   def hello(request):
       context          = {}
       context['hello'] = 'Hello World!'
       return render(request, 'hello.html', context)

    
5. The browser accesses http://127.0.0.1:8000/hello, and the page prints out Hello World!

The following describes the tags of the Django template:

1. if tag:

   {% if ... %}
      ...
   {% elif ... %}
      ...
   {% else %}
      ...
   {% endif %}

    The if condition accepts and , or or not keywords.
2. for tag:

   <ul>
   {% for v in list %}
       <li>{{ v }}</li>
   {% endfor %}
   </ul>
   <ul>
   {% for v in list reversed %}{# reverse iteration#}
       <li>{{ v }}</li>
   {% endfor %}
   </ul>

    
3. ifequal/ifnotequal tags:

   {% ifequal value 'aaa' %}
       If value is equal to aaa, display the section
   {% else %}
       not equal to aaa
   {% endifequal%}

    
4. Annotation tags:

   {# comment#}

    
5. include tag:

   {% include "nav.html" %}

    
6. filter:

   {# to ​​lowercase#}
   {{ name|lower }}
   {# Output the first element, and convert to uppercase#}
   {{ my_list|first|upper }}
   {# The filter can take parameters and display the first 30 words of the variable#}
   {{ bio|truncatewords:"30" }}
   {# format date object#}
   {{ pub_date|date:"F j, Y" }}
   {# Add a backslash before any backslash, single or double quotes#}
   {{ value|addslashes }}
   {# Return the length of the variable#}
   {{ value|length }}

    
7. Template inheritance:

   <p>The first line, the fixed part. </p>
       {% block main %}
          block is the part replaced by the inheritor
       {% endblock %}

    

   {% extends "base.html" %}
    
   {% block main %} replaced
   {% endblock %}

    The end result is:

   The first line, the fixed part.
   replaced

    

This chapter is written here first!