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Introduction to Jinja2 templating engine

Basics of Jinja2

  • What is Jinja2?
  • A templating engine for Python that generates dynamic HTML or other text formats.
  • Integration with Flask:
  • The default templating engine in Flask, allowing seamless dynamic content generation.

Key Features: - Template Inheritance: - Promotes code reuse by defining a base template and extending it in other templates. - Control Structures: - Supports conditional statements (if, if-else) and loops (for).

Control Structures

  1. If Statement: 

    {% if user %}
  <p>Welcome back, {{ user }}!</p>
{% endif %}

  2. If-Else Statement: 

    {% if user %}
  <p>Welcome back, {{ user }}!</p>
{% else %}
  <p>Hello, Guest! Please log in.</p>
{% endif %}

  3. For Loop: 

    <ul>
  {% for item in items %}
    <li>{{ item }}</li>
  {% endfor %}
</ul>

Template Inheritance

  1. Base Template (base.html): 

    <!doctype html>
<html>
  <head>
    <title>{% block title %}My Website{% endblock %}</title>
  </head>
  <body>
    <header>
      <h1>My Website Header</h1>
    </header>

    <main>
      {% block content %}{% endblock %}
    </main>

    <footer>
      <p>My Website Footer</p>
    </footer>
  </body>
</html>

  2. Child Template (index.html): 

    {% extends "base.html" %}

{% block title %}Home - My Website{% endblock %}

{% block content %}
  <h2>Welcome to the Home Page</h2>
  <p>This is the content of the home page.</p>
{% endblock %}

Benefits of Jinja2

  • Separation of Concerns:
  • Separates application logic from presentation logic.
  • Reusability:
  • Reuse common layout elements, enhancing consistency and maintainability.

Jinja2 makes it easy to generate dynamic, reusable, and maintainable HTML by providing powerful features like template inheritance and control structures.