Python 3.7.3 : Using the flask - part 013.

Flask uses Jinga2 template engine.
The Jinga2 template engine uses the following delimiters for escaping from HTML.
We can use this:

• {% ... %} for Statements
• {{ ... }} for Expressions to print to the template output
• {# ... #} for Comments not included in the template output
• # ... ## for Line Statements

The documentation webpage comes with all information about how can be used.
I create a new HTML5 file named layout.html and I will use this like an example:

{% if current_user.is_authenticated %}
...
{% else %}
...
{% endif %}

This file can be add into another file like this:

{% extends "layout.html" %}
{% block content %}
...
{% endblock content %}

For example, my about.html webpage comes with this source code:

{% extends "layout.html" %}
{% block content %}
    
About Page
{% endblock content %}

The routes.py this webpage will have this call:

@app.route("/about")
def about():
    return render_template('about.html', title='About')

In this way, I will add more HTML5 files to the project.