tmpl-fastapi/app/respond.py

import os
import mimetypes
from functools import partial
from typing import Optional, Mapping

from fastapi import Request, Response
from fastapi.responses import RedirectResponse
from fastapi.responses import PlainTextResponse
from fastapi.responses import FileResponse

from starlette.background import BackgroundTask

from .common import templates


def with_redirect(
        url: str = '/',
        code: int = 302,
        *args, **kwargs) -> RedirectResponse:
    """Return a redirect to the page specified in `url`.
    By default, code is 302 so method is changed to GET.
    To leave the same HTTP method, use 307 status code
    or call `with_redirect_307` function.
    `args` and `kwargs` are passed directly
    to the Response contructor

    Args:
        url (str, optional): Target URL, root by default
        code (int, optional): HTTP response code

    Returns:
        FastAPI's RedirectResponse object
    """

    return RedirectResponse(
        url=url,
        status_code=code,
        *args, **kwargs,
    )


def with_text(
        content: str,
        code: int = 200,
        *args, **kwargs) -> PlainTextResponse:
    """Return a plain text to the user.
    `args` and `kwargs` are passed directly
    to the Response contructor

    Args:
        content (str): Plain text content
        code (int, optional): HTTP response code

    Returns:
        FastAPI's PlainTextResponse object
    """

    return PlainTextResponse(
        content=content,
        status_code=code,
        *args, **kwargs,
    )


def with_tmpl(
        name: str,
        request: Request,
        code: int = 200,
        headers: Optional[Mapping[str, str]] = None,
        background: Optional[BackgroundTask] = None,
        **context) -> Response:
    """Render a Jinja2 template and return Response object.
    `response_class` parameter is not needed.
    A small explanation about the `request` function argument:
    ```python
    from fastapi import Request
    from . import respond

    @app.get('/')
    async def main_page(req: Request):  # <--
        return respond.with_tmpl(
            'index.html',
            request=req,  # <--
            ...
        )
    ```
    FastAPI will automatically pass the Request object
    to your function if you specify
    the correct type hint (`: Request`)

    Args:
        name (str): Template filename
        request (Request): FastAPI request object
        code (int, optional): HTTP response code
        headers (Optional[Mapping[str, str]], optional):
            Additional headers, passed to the Response constructor
        background (Optional[BackgroundTask], optional):
            Background task, passed to the Response constructor

    Returns:
        FastAPI's TemplateResponse object
    """

    return templates.TemplateResponse(
        name=name,
        context={
            'request': request,
            **context,
        },
        status_code=code,
        headers=headers,
        background=background,
    )


def with_file(
        path: os.PathLike,
        mime: Optional[str] = None,
        code: int = 200,
        *args, **kwargs) -> FileResponse:
    """Send the file specified in `path`
    automatically guessing its mimetype if `mime` is None.
    `args` and `kwargs` are passed directly
    to the Response contructor

    Args:
        path (os.PathLike): File path
        mime (Optional[str], optional): File mimetype
        code (int, optional): HTTP response code

    Returns:
        FastAPI's FileResponse object
    """

    return FileResponse(
        path=path,
        media_type=(
            mime or 
            mimetypes.guess_type(path)[0]
        ),
        status_code=code,
        *args, **kwargs,
    )


# Aliases
with_template = with_tmpl
with_redirect_302 = partial(
    with_redirect, code=302,
)
with_redirect_307 = partial(
    with_redirect, code=307,
)