Templating - Jinja2Templates

You can use the Jinja2Templates class to render Jinja templates.

Read more about it in the FastAPI docs for Templates.

You can import it directly from fastapi.templating:

from fastapi.templating import Jinja2Templates

fastapi.templating.Jinja2Templates

Jinja2Templates(
    directory=None,
    *,
    context_processors=None,
    env=None,
    **env_options
)

templates = Jinja2Templates("templates")

return templates.TemplateResponse("index.html", {"request": request})

PARAMETER	DESCRIPTION
directory	TYPE: str | PathLike[AnyStr] | Sequence[str | PathLike[AnyStr]] | None DEFAULT: None
context_processors	TYPE: list[Callable[[Request], dict[str, Any]]] | None DEFAULT: None
env	TYPE: Environment | None DEFAULT: None
**env_options	TYPE: Any DEFAULT: {}

Source code in starlette/templating.py

def __init__(
    self,
    directory: str
    | PathLike[typing.AnyStr]
    | typing.Sequence[str | PathLike[typing.AnyStr]]
    | None = None,
    *,
    context_processors: list[typing.Callable[[Request], dict[str, typing.Any]]]
    | None = None,
    env: jinja2.Environment | None = None,
    **env_options: typing.Any,
) -> None:
    if env_options:
        warnings.warn(
            "Extra environment options are deprecated. Use a preconfigured jinja2.Environment instead.",  # noqa: E501
            DeprecationWarning,
        )
    assert jinja2 is not None, "jinja2 must be installed to use Jinja2Templates"
    assert directory or env, "either 'directory' or 'env' arguments must be passed"
    self.context_processors = context_processors or []
    if directory is not None:
        self.env = self._create_env(directory, **env_options)
    elif env is not None:
        self.env = env

    self._setup_env_defaults(self.env)

context_processors instance-attribute

context_processors = context_processors or []

env instance-attribute

env = _create_env(directory, **env_options)

get_template

get_template(name)

PARAMETER	DESCRIPTION
name	TYPE: str

Source code in starlette/templating.py

def get_template(self, name: str) -> jinja2.Template:
    return self.env.get_template(name)

TemplateResponse

TemplateResponse(*args, **kwargs)

PARAMETER	DESCRIPTION
*args	TYPE: Any DEFAULT: ()
**kwargs	TYPE: Any DEFAULT: {}

Source code in starlette/templating.py

def TemplateResponse(
    self, *args: typing.Any, **kwargs: typing.Any
) -> _TemplateResponse:
    if args:
        if isinstance(
            args[0], str
        ):  # the first argument is template name (old style)
            warnings.warn(
                "The `name` is not the first parameter anymore. "
                "The first parameter should be the `Request` instance.\n"
                'Replace `TemplateResponse(name, {"request": request})` by `TemplateResponse(request, name)`.',  # noqa: E501
                DeprecationWarning,
            )

            name = args[0]
            context = args[1] if len(args) > 1 else kwargs.get("context", {})
            status_code = (
                args[2] if len(args) > 2 else kwargs.get("status_code", 200)
            )
            headers = args[2] if len(args) > 2 else kwargs.get("headers")
            media_type = args[3] if len(args) > 3 else kwargs.get("media_type")
            background = args[4] if len(args) > 4 else kwargs.get("background")

            if "request" not in context:
                raise ValueError('context must include a "request" key')
            request = context["request"]
        else:  # the first argument is a request instance (new style)
            request = args[0]
            name = args[1] if len(args) > 1 else kwargs["name"]
            context = args[2] if len(args) > 2 else kwargs.get("context", {})
            status_code = (
                args[3] if len(args) > 3 else kwargs.get("status_code", 200)
            )
            headers = args[4] if len(args) > 4 else kwargs.get("headers")
            media_type = args[5] if len(args) > 5 else kwargs.get("media_type")
            background = args[6] if len(args) > 6 else kwargs.get("background")
    else:  # all arguments are kwargs
        if "request" not in kwargs:
            warnings.warn(
                "The `TemplateResponse` now requires the `request` argument.\n"
                'Replace `TemplateResponse(name, {"context": context})` by `TemplateResponse(request, name)`.',  # noqa: E501
                DeprecationWarning,
            )
            if "request" not in kwargs.get("context", {}):
                raise ValueError('context must include a "request" key')

        context = kwargs.get("context", {})
        request = kwargs.get("request", context.get("request"))
        name = typing.cast(str, kwargs["name"])
        status_code = kwargs.get("status_code", 200)
        headers = kwargs.get("headers")
        media_type = kwargs.get("media_type")
        background = kwargs.get("background")

    context.setdefault("request", request)
    for context_processor in self.context_processors:
        context.update(context_processor(request))

    template = self.get_template(name)
    return _TemplateResponse(
        template,
        context,
        status_code=status_code,
        headers=headers,
        media_type=media_type,
        background=background,
    )