register_fastapi_extensions()

Register jinja_partials with a FastAPI application.

Usage

Source

register_fastapi_extensions(
    app,
    templates,
    max_workers=4,
)

This creates a dedicated ThreadPoolExecutor for rendering partials in async environments. The executor is created when the app’s lifespan starts and is shut down when the lifespan exits - even if startup or shutdown raises - so the app can be started and stopped repeatedly (e.g. multiple TestClient cycles). Outside a lifespan cycle, partials render directly for sync environments, or via a per-registration fallback executor with the same max_workers for async (enable_async=True) environments.

Parameters

app: FastAPI

The FastAPI application instance.

templates: FastAPIJinja2Templates

The Jinja2Templates instance used for rendering.

max_workers: int = 4

Maximum number of worker threads for rendering partials. Defaults to 4.

Raises

PartialsException

If FastAPI is not installed.

Example

Register during app setup:

from fastapi import FastAPI
from fastapi.templating import Jinja2Templates
import jinja_partials

app = FastAPI()
templates = Jinja2Templates(directory="templates")
jinja_partials.register_fastapi_extensions(app, templates)