app.py

from __future__ import annotations

import enum
from dataclasses import dataclass, field
from typing import TYPE_CHECKING, Any, Callable

from litestar.config.allowed_hosts import AllowedHostsConfig
from litestar.config.response_cache import ResponseCacheConfig
from litestar.datastructures import State
from litestar.events.emitter import SimpleEventEmitter
from litestar.types.empty import Empty

if TYPE_CHECKING:
    from contextlib import AbstractAsyncContextManager

    from litestar import Litestar, Response
    from litestar.config.compression import CompressionConfig
    from litestar.config.cors import CORSConfig
    from litestar.config.csrf import CSRFConfig
    from litestar.connection import Request, WebSocket
    from litestar.datastructures import CacheControlHeader, ETag
    from litestar.di import Provide
    from litestar.dto import AbstractDTO
    from litestar.events.emitter import BaseEventEmitterBackend
    from litestar.events.listener import EventListener
    from litestar.logging.config import BaseLoggingConfig
    from litestar.openapi.config import OpenAPIConfig
    from litestar.openapi.spec import SecurityRequirement
    from litestar.plugins import PluginProtocol
    from litestar.static_files.config import StaticFilesConfig
    from litestar.stores.base import Store
    from litestar.stores.registry import StoreRegistry
    from litestar.types import (
        AfterExceptionHookHandler,
        AfterRequestHookHandler,
        AfterResponseHookHandler,
        AnyCallable,
        BeforeMessageSendHookHandler,
        BeforeRequestHookHandler,
        ControllerRouterHandler,
        ExceptionHandlersMap,
        Guard,
        Middleware,
        ParametersMap,
        ResponseCookies,
        ResponseHeaders,
        TypeEncodersMap,
    )
    from litestar.types.callable_types import LifespanHook
    from litestar.types.composite_types import TypeDecodersSequence
    from litestar.types.empty import EmptyType
    from litestar.types.internal_types import TemplateConfigType


__all__ = (
    "AppConfig",
    "ExperimentalFeatures",
)


@dataclass
class AppConfig:
    """The parameters provided to the ``Litestar`` app are used to instantiate an instance, and then the instance is
    passed to any callbacks registered to ``on_app_init`` in the order they are provided.

    The final attribute values are used to instantiate the application object.
    """

    after_exception: list[AfterExceptionHookHandler] = field(default_factory=list)
    """An application level :class:`exception hook handler <.types.AfterExceptionHookHandler>` or list thereof.

    This hook is called after an exception occurs. In difference to exception handlers, it is not meant to return a
    response - only to process the exception (e.g. log it, send it to Sentry etc.).
    """
    after_request: AfterRequestHookHandler | None = field(default=None)
    """A sync or async function executed after the route handler function returned and the response object has been
    resolved.

    Receives the response object which may be any subclass of :class:`Response <.response.Response>`.
    """
    after_response: AfterResponseHookHandler | None = field(default=None)
    """A sync or async function called after the response has been awaited. It receives the
    :class:`Request <.connection.Request>` object and should not return any values.
    """
    allowed_hosts: list[str] | AllowedHostsConfig | None = field(default=None)
    """If set enables the builtin allowed hosts middleware."""
    before_request: BeforeRequestHookHandler | None = field(default=None)
    """A sync or async function called immediately before calling the route handler. Receives the
    :class:`Request <.connection.Request>` instance and any non-``None`` return value is used for the response,
    bypassing the route handler.
    """
    before_send: list[BeforeMessageSendHookHandler] = field(default_factory=list)
    """An application level :class:`before send hook handler <.types.BeforeMessageSendHookHandler>` or list thereof.

    This hook is called when the ASGI send function is called.
    """
    cache_control: CacheControlHeader | None = field(default=None)
    """A ``cache-control`` header of type :class:`CacheControlHeader <.datastructures.CacheControlHeader>` to add to
    route handlers of this app.

    Can be overridden by route handlers.
    """
    compression_config: CompressionConfig | None = field(default=None)
    """Configures compression behaviour of the application, this enabled a builtin or user defined Compression
    middleware.
    """
    cors_config: CORSConfig | None = field(default=None)
    """If set this enables the builtin CORS middleware."""
    csrf_config: CSRFConfig | None = field(default=None)
    """If set this enables the builtin CSRF middleware."""
    debug: bool = field(default=False)
    """If ``True``, app errors rendered as HTML with a stack trace."""
    dependencies: dict[str, Provide | AnyCallable] = field(default_factory=dict)
    """A string keyed dictionary of dependency :class:`Provider <.di.Provide>` instances."""
    dto: type[AbstractDTO] | None | EmptyType = field(default=Empty)
    """:class:`AbstractDTO <.dto.base_dto.AbstractDTO>` to use for (de)serializing and validation of request data."""
    etag: ETag | None = field(default=None)
    """An ``etag`` header of type :class:`ETag <.datastructures.ETag>` to add to route handlers of this app.

    Can be overridden by route handlers.
    """
    event_emitter_backend: type[BaseEventEmitterBackend] = field(default=SimpleEventEmitter)
    """A subclass of :class:`BaseEventEmitterBackend <.events.emitter.BaseEventEmitterBackend>`."""
    exception_handlers: ExceptionHandlersMap = field(default_factory=dict)
    """A dictionary that maps handler functions to status codes and/or exception types."""
    guards: list[Guard] = field(default_factory=list)
    """A list of :class:`Guard <.types.Guard>` callables."""
    include_in_schema: bool | EmptyType = field(default=Empty)
    """A boolean flag dictating whether  the route handler should be documented in the OpenAPI schema"""
    lifespan: list[Callable[[Litestar], AbstractAsyncContextManager] | AbstractAsyncContextManager] = field(
        default_factory=list
    )
    """A list of callables returning async context managers, wrapping the lifespan of the ASGI application"""
    listeners: list[EventListener] = field(default_factory=list)
    """A list of :class:`EventListener <.events.listener.EventListener>`."""
    logging_config: BaseLoggingConfig | None = field(default=None)
    """An instance of :class:`BaseLoggingConfig <.logging.config.BaseLoggingConfig>` subclass."""
    middleware: list[Middleware] = field(default_factory=list)
    """A list of :class:`Middleware <.types.Middleware>`."""
    on_shutdown: list[LifespanHook] = field(default_factory=list)
    """A list of :class:`LifespanHook <.types.LifespanHook>` called during application shutdown."""
    on_startup: list[LifespanHook] = field(default_factory=list)
    """A list of :class:`LifespanHook <.types.LifespanHook>` called during application startup."""
    openapi_config: OpenAPIConfig | None = field(default=None)
    """Defaults to :data:`DEFAULT_OPENAPI_CONFIG <litestar.app.DEFAULT_OPENAPI_CONFIG>`"""
    opt: dict[str, Any] = field(default_factory=dict)
    """A string keyed dictionary of arbitrary values that can be accessed in :class:`Guards <.types.Guard>` or
    wherever you have access to :class:`Request <.connection.Request>` or :class:`ASGI Scope <litestar.types.Scope>`.

    Can be overridden by routers and router handlers.
    """
    parameters: ParametersMap = field(default_factory=dict)
    """A mapping of :class:`Parameter <.params.Parameter>` definitions available to all application paths."""
    path: str = field(default="")
    """A base path that prefixed to all route handlers, controllers and routers associated with the
    application instance.

    .. versionadded:: 2.8.0
    """
    pdb_on_exception: bool = field(default=False)
    """Drop into the PDB on an exception"""
    plugins: list[PluginProtocol] = field(default_factory=list)
    """List of :class:`SerializationPluginProtocol <.plugins.SerializationPluginProtocol>`."""
    request_class: type[Request] | None = field(default=None)
    """An optional subclass of :class:`Request <.connection.Request>` to use for http connections."""
    response_class: type[Response] | None = field(default=None)
    """A custom subclass of :class:`Response <.response.Response>` to be used as the app's default response."""
    response_cookies: ResponseCookies = field(default_factory=list)
    """A list of :class:`Cookie <.datastructures.Cookie>`."""
    response_headers: ResponseHeaders = field(default_factory=list)
    """A string keyed dictionary mapping :class:`ResponseHeader <.datastructures.ResponseHeader>`."""
    response_cache_config: ResponseCacheConfig = field(default_factory=ResponseCacheConfig)
    """Configures caching behavior of the application."""
    return_dto: type[AbstractDTO] | None | EmptyType = field(default=Empty)
    """:class:`AbstractDTO <.dto.base_dto.AbstractDTO>` to use for serializing outbound response
    data.
    """
    route_handlers: list[ControllerRouterHandler] = field(default_factory=list)
    """A required list of route handlers, which can include instances of :class:`Router <.router.Router>`,
    subclasses of :class:`Controller <.controller.Controller>` or any function decorated by the route handler
    decorators.
    """
    security: list[SecurityRequirement] = field(default_factory=list)
    """A list of dictionaries that will be added to the schema of all route handlers in the application. See
    :data:`SecurityRequirement <.openapi.spec.SecurityRequirement>` for details.
    """
    signature_namespace: dict[str, Any] = field(default_factory=dict)
    """A mapping of names to types for use in forward reference resolution during signature modeling."""
    signature_types: list[Any] = field(default_factory=list)
    """A sequence of types for use in forward reference resolution during signature modeling.

    These types will be added to the signature namespace using their ``__name__`` attribute.
    """
    state: State = field(default_factory=State)
    """A :class:`State` <.datastructures.State>` instance holding application state."""
    static_files_config: list[StaticFilesConfig] = field(default_factory=list)
    """An instance or list of :class:`StaticFilesConfig <.static_files.StaticFilesConfig>`."""
    stores: StoreRegistry | dict[str, Store] | None = None
    """Central registry of :class:`Store <.stores.base.Store>` to be made available and be used throughout the
    application. Can be either a dictionary mapping strings to :class:`Store <.stores.base.Store>` instances, or an
    instance of :class:`StoreRegistry <.stores.registry.StoreRegistry>`.
    """
    tags: list[str] = field(default_factory=list)
    """A list of string tags that will be appended to the schema of all route handlers under the application."""
    template_config: TemplateConfigType | None = field(default=None)
    """An instance of :class:`TemplateConfig <.template.TemplateConfig>`."""
    type_decoders: TypeDecodersSequence | None = field(default=None)
    """A sequence of tuples, each composed of a predicate testing for type identity and a msgspec hook for deserialization."""
    type_encoders: TypeEncodersMap | None = field(default=None)
    """A mapping of types to callables that transform them into types supported for serialization."""
    websocket_class: type[WebSocket] | None = field(default=None)
    """An optional subclass of :class:`WebSocket <.connection.WebSocket>` to use for websocket connections."""
    multipart_form_part_limit: int = field(default=1000)
    """The maximal number of allowed parts in a multipart/formdata request. This limit is intended to protect from
    DoS attacks."""
    experimental_features: list[ExperimentalFeatures] | None = None

    def __post_init__(self) -> None:
        """Normalize the allowed hosts to be a config or None.

        Returns:
            Optional config.
        """
        if self.allowed_hosts and isinstance(self.allowed_hosts, list):
            self.allowed_hosts = AllowedHostsConfig(allowed_hosts=self.allowed_hosts)


class ExperimentalFeatures(str, enum.Enum):
    DTO_CODEGEN = "DTO_CODEGEN"