The Django template language
This is one of the most important facilities provided by Django Templates. A Django template is a text document or a Python string marked-up using the Django template language. Some constructs are recognized and interpreted by the template engine. The main ones are variables and tags. As we used for the loop in the above example, we used it as a tag. similarly, we can use various other conditions such as if, else, if-else, empty, etc. The main characteristics of Django Template language are Variables, Tags, Filters, and Comments.
Jinja Variables
Variables output a value from the context, which is a dict-like object mapping keys to values. The context object we sent from the view can be accessed in the template using variables of Django Template.
Syntax: {{ variable_name }}
Example: Variables are surrounded by {{ and }} like this:
My first name is {{ first_name }}. My last name is {{ last_name }}.
With a context of {‘first_name’: ‘Naveen’, ‘last_name’: ‘Arora’}, this template renders to:
My first name is Naveen. My last name is Arora.
To know more about Django Template Variables visit – variables – Django Templates
Jinja Tags
Tags provide arbitrary logic in the rendering process. For example, a tag can output content, serve as a control structure e.g. an “if” statement or a “for” loop, grab content from a database, or even enable access to other template tags.
Syntax: {% tag_name %}
Example: Tags are surrounded by {% and %} like this:
{% csrf_token %}
Most tags accept arguments, for example :
{% cycle 'odd' 'even' %}
| Commonly used Tags | ||
|---|---|---|
| Comment | cycle | extends |
| if | for loop | for … empty loop |
| Boolean Operators | firstof | include |
| lorem | now | url |
Filters
Django Template Engine provides filters that are used to transform the values of variables and tag arguments. We have already discussed major Django Template Tags. Tags can’t modify the value of a variable whereas filters can be used for incrementing the value of a variable or modifying it to one’s own need.
Syntax: {{ variable_name | filter_name }}
Filters can be “chained.” The output of one filter is applied to the next. {{ text|escape|linebreaks }} is a common idiom for escaping text contents, then converting line breaks to <p> tags.
Example: {{ value | length }}
If value is [‘a’, ‘b’, ‘c’, ‘d’], the output will be 4.
| Major Template Filters | ||
|---|---|---|
| add | addslashes | capfirst |
| center | cut | date |
| default | dictsort | divisibleby |
| escape | filesizefodivisible byrmat | first |
| join | last | length |
| line numbers | lower | make_list |
| random | slice | slugify |
| time | timesince | title |
| unordered_list | upper | wordcount |
Comments
Template ignores everything between {% comment %} and {% end comment %}. An optional note may be inserted in the first tag. For example, this is useful when commenting out code for documenting why the code was disabled.
Syntax: {% comment 'comment_name' %}
{% endcomment %}
Example :
{% comment "Optional note" %}
Commented out text with {{ create_date|date:"c" }}
{% endcomment %}
To know more about using comments in Templates, visit comment – Django template tags
Template Inheritance
The most powerful and thus the most complex part of Django’s template engine is template inheritance. Template inheritance allows you to build a base “skeleton” template that contains all the common elements of your site and defines blocks that child templates can override. extends tag is used for the inheritance of templates in Django. One needs to repeat the same code again and again. Using extends we can inherit templates as well as variables.
Syntax: {% extends 'template_name.html' %}
Example: Assume the following directory structure:
dir1/
template.html
base2.html
my/
base3.html
base1.html
In template.html, the following paths would be valid:
{% extends "./base2.html" %}
{% extends "../base1.html" %}
{% extends "./my/base3.html" %}
To know more about Template inheritance and extends, visit extends – Django Template Tags
Django Templates
Templates are the third and most important part of Django’s MVT Structure. A template in Django is basically written in HTML, CSS, and Javascript in a .html file. Django framework efficiently handles and generates dynamic HTML web pages that are visible to the end-user. Django mainly functions with a backend so, in order to provide a frontend and provide a layout to our website, we use templates. There are two methods of adding the template to our website depending on our needs.
We can use a single template directory which will be spread over the entire project. For each app of our project, we can create a different template directory.