minijinja 0.30.0

An experimental Python binding of the Rust MiniJinja template engine.

MiniJinja for Python: a powerful template engine for Rust and Python

minijinja-py is an experimental binding of MiniJinja to Python. It has somewhat limited functionality compared to the Rust version. These bindings use maturin and pyo3.

You might want to use MiniJinja instead of Jinja2 when the full feature set of Jinja2 is not required and you want to have the same rendering experience of a data set between Rust and Python.

With these bindings MiniJinja can render some Python objects and values that are passed to templates, but there are clear limitations with regards to what can be done.

To install MiniJinja for Python you can fetch the package from PyPI:

$ pip install minijinja

Basic API

The basic API is hidden behind the Environment object. It behaves almost entirely like in minijinja with some Python specific changes. For instance instead of env.set_debug(True) you use env.debug = True. Additionally instead of using add_template or attaching a source you either pass a dictionary of templates directly to the environment or a loader function.

from minijinja import Environment

env = Environment(templates={
    "template_name": "Template source"
})

# alternatively

def loader(template_name):
    if template_name == "template_name":
        return "Template soruce"
    return None

env = Environment(loader=loader)

To render a template you can use the render_template method:

result = env.render_template('template_name', var1="value 1", var2="value 2")
print(result)

Utility

MiniJinja attemps a certain level of compatibiliy with Jinja2, but it does not try to achieve this at all costs. As a result you will notice that quite a few templates will refuse to render with MiniJinja despite the fact that they probably look quite innocent. It is however possible to write templates that render to the same results for both Jinja2 and MiniJinja. This raises the question why you might want to use MiniJinja.

The main benefit would be to achieve the exact same results in both Rust and Python. Additionally MiniJinja has a stronger sandbox than Jinja2 and might perform ever so slightly better in some situations. However you should be aware that due to the marshalling that needs to happen in either direction there is a certain amount of loss of information.

Runtime Behavior

MiniJinja uses it's own runtime model which is not matching the Python runtime model. As a result there are clear gaps in beahvior between the two and only limited effort is made to bridge them. For instance you will be able to call some methods of types, but for instance builtins such as dicts and lists do not expose their methods on the MiniJinja side. This means that it's very intentional that if you pass a dictionary to MiniJinja, the Python .items() method is unavailable.

Here is what this means for some basic types:

• Python dictionaries and lists (as well as other objects that behave as sequences) appear in the MiniJinja side as native lists. They do not expose any specific other behavior and when they move back to the Python side they will appear as basic lists. Specifically this means that a tuple (which does not exist in MiniJinja) when moving from Python to MiniJinja turns into a list and will remain a list when it moves back.
• Python objects are represented in MiniJinja similarly to dicts, but they retain all their meaningful Python APIs. This means they stringify via __str__ and they allow the MiniJinja code to call their non-underscored methods. Note that there is no extra security layer in use at the moment so take care of what you pass there.
• MiniJinja's python binding understand what __html__ is when it exists on a string subclass. This means that a markupsafe.Markup object will appear as safe string in MiniJinja. This information can also flow back to Python again.

Sponsor

If you like the project and find it useful you can become a sponsor.

License and Links

• Documentation
• Examples
• Issue Tracker
• MiniJinja Playground
• License: Apache-2.0