| | Template Inheritance |
| | ==================== |
| | |
| | The most powerful part of Jinja 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. |
| | |
| | Sounds complicated but is very basic. It's easiest to understand it by starting |
| | with an example. |
| | |
| | |
| | Base Template |
| | ------------- |
| | |
| | This template, which we'll call :file:`layout.html`, defines a simple HTML skeleton |
| | document that you might use for a simple two-column page. It's the job of |
| | "child" templates to fill the empty blocks with content: |
| | |
| | .. sourcecode:: html+jinja |
| | |
| | <!doctype html> |
| | <html> |
| | <head> |
| | {% block head %} |
| | <link rel="stylesheet" href="{{ url_for('static', filename='style.css') }}"> |
| | <title>{% block title %}{% endblock %} - My Webpage</title> |
| | {% endblock %} |
| | </head> |
| | <body> |
| | <div id="content">{% block content %}{% endblock %}</div> |
| | <div id="footer"> |
| | {% block footer %} |
| | © Copyright 2010 by <a href="http://domain.invalid/">you</a>. |
| | {% endblock %} |
| | </div> |
| | </body> |
| | </html> |
| | |
| | In this example, the ``{% block %}`` tags define four blocks that child templates |
| | can fill in. All the `block` tag does is tell the template engine that a |
| | child template may override those portions of the template. |
| | |
| | Child Template |
| | -------------- |
| | |
| | A child template might look like this: |
| | |
| | .. sourcecode:: html+jinja |
| | |
| | {% extends "layout.html" %} |
| | {% block title %}Index{% endblock %} |
| | {% block head %} |
| | {{ super() }} |
| | <style type="text/css"> |
| | .important { color: #336699; } |
| | </style> |
| | {% endblock %} |
| | {% block content %} |
| | <h1>Index</h1> |
| | <p class="important"> |
| | Welcome on my awesome homepage. |
| | {% endblock %} |
| | |
| | The ``{% extends %}`` tag is the key here. It tells the template engine that |
| | this template "extends" another template. When the template system evaluates |
| | this template, first it locates the parent. The extends tag must be the |
| | first tag in the template. To render the contents of a block defined in |
| | the parent template, use ``{{ super() }}``. |
| | |
