jinja2-inflection

A Jinja2 extension that integrates the inflection library's string transformation functions as template filters.

Overview

jinja2-inflection is a Jinja2 extension that provides a set of filters for string transformation using the inflection library. This package allows you to easily manipulate strings in your Jinja2 templates by converting between different naming conventions, pluralizing words, and more.

Key Features

• String Transformation Filters: Access a variety of filters that apply inflection functions to strings in templates.
• Easy Integration: Seamlessly add the extension to your Jinja2 environment, making the filters available in all templates.
• Reusable Logic: Encapsulate inflection functions as filters to promote code reuse and consistency across templates.
• Parameter Support: Filters support optional parameters for customized string transformations.

Filters

The extension provides the following filters:

Filters with Parameters

Some filters support optional parameters:

• camelize: {{ 'product_category' | camelize(uppercase_first_letter=False) }} → productCategory
• parameterize: {{ 'Donald E. Knuth' | parameterize(separator='_') }} → donald_e_knuth

Installation

Using pip

pip install jinja2-inflection

Using uv

uv pip install jinja2-inflection

Using Poetry

poetry add jinja2-inflection

Using PDM

pdm add jinja2-inflection

Usage

Basic Usage

from jinja2 import Environment
from jinja2_inflection import InflectionExtension

# Set up Jinja2 environment with the extension
env = Environment(extensions=[InflectionExtension])

# Use filters in templates
examples = [
    # Basic string transformations
    "{{ 'snake_case_string' | camelize }}",  # Outputs: "SnakeCaseString"
    "{{ 'first_name' | dasherize }}",  # Outputs: "first-name"
    "{{ 'employee_salary' | humanize }}",  # Outputs: "Employee salary"
    "{{ 'DeviceType' | underscore }}",  # Outputs: "device_type"
    # Number transformations
    "{{ 1 | ordinal }}",  # Outputs: "st"
    "{{ 2 | ordinalize }}",  # Outputs: "2nd"
    # Pluralization and singularization
    "{{ 'octopus' | pluralize }}",  # Outputs: "octopi"
    "{{ 'mice' | singularize }}",  # Outputs: "mouse"
    # Other transformations
    "{{ 'UserAccount' | tableize }}",  # Outputs: "user_accounts"
    "{{ 'api_responses' | titleize }}",  # Outputs: "Api Responses"
    "{{ 'café' | transliterate }}",  # Outputs: "cafe"
    # Using parameters
    "{{ 'product_category' | camelize(uppercase_first_letter=False) }}",  # Outputs: "productCategory"
    "{{ 'Donald E. Knuth' | parameterize(separator='_') }}",  # Outputs: "donald_e_knuth"
]

# Render and print each example
for example in examples:
    template = env.from_string(example)
    print(f"{example} → {template.render()}")

Using with FastAPI

from fastapi import FastAPI, Request
from fastapi.templating import Jinja2Templates
from jinja2_inflection import InflectionExtension

app = FastAPI()

# Configure Jinja2Templates with the extension
templates = Jinja2Templates(directory="templates")
templates.env.add_extension(InflectionExtension)


@app.get("/")
async def index(request: Request):
    return templates.TemplateResponse(
        "index.html", {"request": request, "snake_case_var": "user_profile"}
    )

In your template (templates/index.html):

<!DOCTYPE html>
<html>
<head>
    <title>FastAPI with jinja2-inflection</title>
</head>
<body>
    <h1>Variable in CamelCase: {{ snake_case_var | camelize }}</h1>
    <!-- Outputs: Variable in CamelCase: UserProfile -->
</body>
</html>

Using with Starlette

from starlette.applications import Starlette
from starlette.routing import Route
from starlette.templating import Jinja2Templates
from starlette.requests import Request
from jinja2_inflection import InflectionExtension

# Configure Jinja2Templates with the extension
templates = Jinja2Templates(directory="templates")
templates.env.add_extension(InflectionExtension)


async def homepage(request: Request):
    return templates.TemplateResponse(
        "index.html", {"request": request, "table_name": "user_accounts"}
    )


routes = [Route("/", homepage)]

app = Starlette(debug=True, routes=routes)

Using with Flask

from flask import Flask, render_template
from jinja2_inflection import InflectionExtension

app = Flask(__name__)
app.jinja_env.add_extension(InflectionExtension)


@app.route("/")
def index():
    return render_template(
        "index.html"
    )  # Now your templates can use inflection filters

Using with Django

In your Django settings:

TEMPLATES = [
    {
        'BACKEND': 'django.template.backends.jinja2.Jinja2',
        'DIRS': [...],
        'APP_DIRS': True,
        'OPTIONS': {
            'environment': 'myapp.jinja2.environment',
            ...
        },
    },
]

Then in myapp/jinja2.py:

from jinja2 import Environment
from jinja2_inflection import InflectionExtension


def environment(**options):
    env = Environment(**options)
    env.add_extension(InflectionExtension)
    return env

Requirements

• Python 3.13+
• Jinja2 3.1.6+
• inflection 0.5.1+

License

BSD-3-Clause

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add some amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

Acknowledgments

• This project uses the inflection library to provide powerful string transformation capabilities. Special thanks to the contributors of the inflection library for their work.
• Additionally, we acknowledge the Jinja2 project for providing a robust templating engine that makes this extension possible.