Django template
In the previous chapter we use django.http.HttpResponse ()
to output "Hello World!". This way the data and view mixed together,
do not meet the Django MVC thinking.
In this section we will detail the application of the Django
template, which is a text that separates the presentation and content of the
document.
Template application example
We will follow the previous section of the project will be
in the HelloWorld directory to create templates directory and create hello.html
file, the entire directory structure is as follows:
HelloWorld/
|-- HelloWorld
| |-- __init__.py
| |-- __init__.pyc
| |-- settings.py
| |-- settings.pyc
| |-- urls.py
| |-- urls.pyc
| |-- view.py
| |-- view.pyc
| |-- wsgi.py
| `--
wsgi.pyc
|-- manage.py
`-- templates
`-- hello.html
HelloWorld/templates/hello.html File code:
<H1> {{hello}} </ h1>
From the template we know that variables use double
parentheses.
Next we need to explain the path to the template file to
Django, modify HelloWorld / settings.py, modify DIRS in TEMPLATES to [BASE_DIR
+ "/ templates", as follows:
HelloWorld/HelloWorld/settings.py File code:
We now modify view.py, add a new object for submitting data
to the template:
HelloWorld/HelloWorld/view.py File code:
# -*- 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)
You can see that here we use render to replace the
previously used HttpResponse. Render also uses a dictionary context as a
parameter.
The key "hello" of the element in the context
dictionary corresponds to the variable "{{hello}}" in the template.
And then visit visit http://127.0.0.1:8000/hello, you can
see the page:
So we completed the use of templates to output data, in
order to achieve data and view separation.
Next we will introduce the syntax rules commonly used in
templates.
Django template tags
If / else tag
The basic syntax is as follows:
{% if condition %} ... display {% endif %}Else
{% if condition1 %} ... display 1 {% elif condiiton2 %} ... display 2 {% else %} ... display 3 {% endif %}
According to the conditions to determine whether the output. If / else support nesting.
The {% if%} tag accepts the, or or not keywords to determine multiple variables, or negate the variables, for example:
{% if athlete_list and coach_list %} Both the athletes and coaches variables are available. {% endif %}
For the label
{% For%} allows us to iterate over a sequence.
Similar to the case of Python's for statement, the loop syntax is for X in Y, Y is the sequence to be iterated and X is the name of the variable used in each particular loop.
In each iteration, the template system renders all content between {% for%} and {% endfor%}.
For example, given an athlete list for the athlete_list variable, we can use the following code to display the list:
<ul> {% for athlete in athlete_list %} <li>{{ athlete.name }}</li> {% endfor %} </ul>Add a reverse to the label so that the list is reversed by iteration:
{% for athlete in athlete_list reversed %} ... {% endfor %}Can be nested using {% for%} tags:
{% for athlete in athlete_list %} <h1>{{ athlete.name }}</h1> <ul> {% for sport in athlete.sports_played %} <li>{{ sport }}</li> {% endfor %} </ul> {% endfor %}Ifequal / ifnotequal tag
The {% ifequal%} tag compares the two values and displays all the values in {% ifequal%} and {% endifequal%} when they are equal.
The following example compares two template variables user and currentuser:
{% ifequal user currentuser %} <h1>Welcome!</h1> {% endifequal %}Similar to {% if%}, {% ifequal%} Supports optional {% else%} tags: 8
{% ifequal section 'sitenews' %} <h1>Site News</h1> {% else %} <h1>No News Here</h1> {% endifequal %}
Annotation label Django comment using {# #}.
{# This is a comment #}
filter
The template filter can be modified before the variable is displayed, and the filter uses the pipe character as follows:
{{ name|lower }}
{{Name}} After the variable is processed by the filter, the document uppercase conversion text is lowercase. The filter pipe can be * jack *, both said that the output of a filter pipe can be used as the input of the next pipe:
{{ my_list|first|upper }}
The above example converts the first element and converts it to uppercase. Some filters have parameters. The parameters of the filter follow the colon and are always enclosed in double quotation marks. E.g:
{{ bio|truncatewords:"30" }}This will display the first 30 words of the variable bio. Other filters: Addslashes: Adds a backslash to any backslash, single or double quotation marks. Date: format the date or datetime object in the specified format string parameter, instance:
{{ pub_date|date:"F j, Y" }}Length: Returns the length of the variable. Include tags The {% include%} tag allows you to include the contents of other templates in the template. The following example contains the nav.html template:
{% include "nav.html" %}Template inheritance Templates can be reused in an inherited manner. Next we add the base.html file in the templates directory of the previous project, as follows:
HelloWorld/templates/base.html File Code:
!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Django Girls Blog</title>
</head>
<body>
<h1>Django Girls Blog</h1>
<p>[<Post:My second Post>],[<Post:My first Post>]</p>
{% block mainbody %}
<p>original</p>
{% endblock %}
</body>
</html>
In the above code, the block tag named mainbody is the part that can be replaced by the successor.
All {% block%} tags tell the template engine that the subpages can override these sections.
Hello.html inherited base.html, and replace the specific block, hello.html modified code as follows:
The first line of code shows that hello.html inherits the base.html file. You can see that the same name of the block tag here to replace the corresponding base.html block.
Re-visit the address http://127.0.0.1:8000/hello, the output is as follows:
