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diff --git a/jinja.html.markdown b/jinja.html.markdown new file mode 100644 index 00000000..7e5b8e96 --- /dev/null +++ b/jinja.html.markdown @@ -0,0 +1,270 @@ +--- +language: Jinja +contributors: + - ["Adaías Magdiel", "https://github.com/AdaiasMagdiel"] +filename: learn-jinja.j2 +--- + +## Getting Started with Jinja + +Jinja is a fast, expressive, and extensible templating engine for Python +applications. + +Jinja includes a lot of functionalities, such as: +- Template inheritance and inclusion; +- Defining and importing macros within templates; +- Security mechanisms to prevent XSS attacks; +- A sandboxed environment that can safely render untrusted templates; +- Extensible filters, tests, functions, and even syntax. + +A Jinja template is simply a text file. Jinja doesn't require a specific +extension, but it's common to use `.j2` or `.jinja` to make it easier for +some IDEs. + +There are a few kinds of delimiters. The default Jinja delimiters are configured +as follows: + +- `{% ... %}` for Statements +- `{{ ... }}` for Expressions to print to the template output +- `{# ... #}` for Comments not included in the template output + +```jinja +{# This is an example of a comment. #} + +{# + You can use this syntax + to write multiline comments + as well. +#} +``` + + +## VARIABLES + +```jinja +{# You have the option to access variables from the context passed to the template #} + +{{ foo }} + +{# + Additionally, you can use a dot (.) to access attributes of a variable or + use Python syntax, using [] +#} + +{{ foo.bar }} +{{ foo['bar'] }} + +{# Within the template, you can define variables as well #} + +{% set name = "Magdiel" %} +{{ name }} +``` + +## Loops + +```html +<h1>Members</h1> +<ul> +{% for user in users %} + <li>{{ user.username }}</li> +{% endfor %} +</ul> + + +<div> +{% for key, value in my_dict.items() %} + <p>{{ key }}</p> - <p>{{ value }}</p> +{% endfor %} +</div> + + +<div> +{% for idx, url in enumerate(urls) %} + <a href="{{ url }}">Go to url {{ idx + 1 }}</a> +{% endfor %} +</div> +``` + +## Conditionals + +The if statement in Jinja is similar to the if statement in Python. It is +commonly used to check if a variable is defined, not empty, and not false in +its most basic form. + +```html +{% if users %} +<ul> +{% for user in users %} + <li>{{ user.username }}</li> +{% endfor %} +</ul> +{% endif %} + + +{# For multiple branches, elif and else can be used like in Python. #} + + +{% if message.status == "error" %} + <p class="text-red-400">{{ message.content }}</p> +{% elif message.status == "success" %} + <p class="text-green-400">{{ message.content }}</p> +{% else %} + <p class="text-blue-400">{{ message.content }}</p> +{% endif %} +``` + +## Template Inheritance + +One of the most powerful features of Jinja is template inheritance. You can +create a base layout with predefined blocks that you can extend in another file +and override with your own content. + +```html +{# file: base.html.j2 #} + +<!DOCTYPE html> +<html lang="en"> +<head> + {% block head %} + <meta charset="UTF-8"> + <meta name="viewport" content="width=device-width, initial-scale=1.0"> + <title>{% block title %}{% endblock title %} - Learning Jinja</title> + {% endblock head %} +</head> +<body> + <main> + {% block content %}{% endblock %} + {# the endblock tag doesn't need the name of the block #} + </main> +</body> +</html> + + + +{# file: child.html.j2 #} + +{% extends "base.html.j2" %} + +{% block head %} + {{ super() }} + <script> + console.log("There's a console.log here") + </script> +{% endblock %} + +{% block title %}Home{% endblock %} + +{% block content %} + <h1>Index</h1> + <p>Welcome to my home homepage.</p> +{% endblock %} + + + +{# RESULT #} + +<!DOCTYPE html> +<html lang="en"> +<head> + <meta charset="UTF-8"> + <meta name="viewport" content="width=device-width, initial-scale=1.0"> + <title>Home - Learning Jinja</title> + <script> + console.log("There's a console.log here") + </script> +</head> +<body> + <main> + <h1>Index</h1> + <p>Welcome to my home homepage.</p> + </main> +</body> +</html> + +``` + +### Including Content + +You can include content from another template on your current template using +the `{% include "template/path" %}` tag. + +```html + +{# file: footer.html.j2 #} + +<footer> + <p>© 2024 - John Doe</p> +</footer> + + + +{# file: index.html.j2 #} +... +<body> + <main> + <h1>Hi! I'm John Doe!</h1> + </main> + {% include "footer.html.j2" %} +</body> +... + + + +{# RESULT #} + +... +<body> + <main> + <h1>Hi! I'm John Doe!</h1> + </main> + <footer> + <p>© 2024 - John Doe</p> + </footer> +</body> +... +``` + +Variables passed to the main template can also be used in the include, as the +included template has access to the context of the main template. + +```html +{# file: greetings.html.j2 #} + +<p>I'm the {{ name }} and i like to {{ hobby }}.</p> + + + +{# file: index.html.j2 #} + +{% set name = "Captain Nemo" %} +{% set hobby = "navigate through the depths of the ocean" %} + +<div> + {% include "greetings.html.j2" %} +</div> + + + +{# RESULT #} + +<div> + <p>I'm the Captain Nemo and i like to navigate through the depths of the ocean.</p> +</div> +``` + +## Macros + +Macros are basically like functions in another languages. You can define macros with or without arguments and reuse them in various parts of your template. + +```html +{% macro input(value="", type="text", placeholder="") -%} + <input type="{{ type }}" value="{{ value }}" placeholder="{{ placeholder }}"> +{%- endmacro %} + +<p>{{ input(placeholder="Your username") }}</p> +<p>{{ input(type="password") }}</p> +``` + +## Official Documentation + +To learn more, access the [official documentation](https://jinja.palletsprojects.com/en/). |