Jinja: Introduction to Macros and Imports
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Jinja2 supports putting reusable code into macros, which can be imported from other templates. This is a powerful feature that works similarly to Python’s import statements, allowing you to organize your code and make your templates more modular. A key thing to remember is that imports are cached, and imported templates don’t have access to the current template’s variables by default.
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Two Ways to Import
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There are two primary methods for importing templates:
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- Import a complete template into a variable: This method gives you access to all public macros and top-level variables from the imported file via the variable.
- Request specific macros or exported variables: This allows you to cherry-pick what you need from the imported template, avoiding a cluttered namespace.
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Code Demonstration
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Here are examples of both import methods. First, let’s assume we have a file named `forms.html` with a macro for rendering a text input:
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forms.html (the file to be imported)
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{% macro text_input(label, name, value='') %}n <label>{{ label }}</label>n <input type="text" name="{{ name }}" value="{{ value }}">n{% endmacro %}n
Method 1: Importing the entire template
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{% import 'forms.html' as forms %}nn<p>{{ forms.text_input('Username', 'username') }}</p>n
Method 2: Importing specific macros
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{% from 'forms.html' import text_input %}nn<p>{{ text_input('Email', 'email') }}</p>n
Both methods achieve the same result, but the `from … import …` syntax is cleaner if you only need a single macro or variable.
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