oidc-fastapi-test/src/oidc_test/settings.py

from os import environ
import string
import random
from typing import Type, Tuple
from pathlib import Path

from pydantic import BaseModel, computed_field, AnyUrl
from pydantic_settings import (
    BaseSettings,
    SettingsConfigDict,
    PydanticBaseSettingsSource,
    YamlConfigSettingsSource,
)
from starlette.requests import Request


class Resource(BaseModel):
    """A resource with an URL that can be accessed with an OAuth2 access token"""

    resource_name: str
    name: str
    url: str


class AuthProviderSettings(BaseModel):
    """Auth provider, can also be a resource server"""

    id: str
    name: str
    url: str
    client_id: str
    client_secret: str = ""
    # For PKCE (not implemented yet)
    code_challenge_method: str | None = None
    hint: str = "No hint"
    resources: list[Resource] = []
    account_url_template: str | None = None
    info_url: str | None = (
        None  # Used eg. for Keycloak's public key (see https://stackoverflow.com/questions/54318633/getting-keycloaks-public-key)
    )
    public_key: str | None = None
    public_key_url: str | None = None
    signature_alg: str = "RS256"
    resource_provider_scopes: list[str] = []
    session_key: str = "sid"
    skip_verify_signature: bool = True
    disabled: bool = False

    @computed_field
    @property
    def openid_configuration(self) -> str:
        return self.url + "/.well-known/openid-configuration"

    @computed_field
    @property
    def token_url(self) -> str:
        return "auth/" + self.id

    def get_account_url(self, request: Request, user: dict) -> str | None:
        if self.account_url_template:
            if not (self.url.endswith("/") or self.account_url_template.startswith("/")):
                sep = "/"
            else:
                sep = ""
            return self.url + sep + self.account_url_template.format(request=request, user=user)
        else:
            return None


class ResourceProvider(BaseModel):
    id: str
    name: str
    base_url: AnyUrl
    resources: list[Resource] = []


class AuthSettings(BaseModel):
    show_session_details: bool = False
    providers: list[AuthProviderSettings] = []
    swagger_provider: str = ""


class Insecure(BaseModel):
    """Warning: changing these defaults are only suitable for debugging"""

    skip_verify_signature: bool = False


class DB(BaseModel):
    host: str = "localhost"
    port: int = 5432
    db: str = "oidc-test"
    user: str = "oidc-test"
    password: str = "oidc-test"
    debug: bool = False
    pool_size: int = 10
    max_overflow: int = 10
    echo: bool = False

    @property
    def sqla_url(self):
        return (
            f"postgresql+asyncpg://{self.user}:{self.password}@{self.host}:{self.port}/{self.db}"
        )

    def get_pg_url(self):
        return f"postgresql://{self.user}:{self.password}@{self.host}:{self.port}/{self.db}"


class Settings(BaseSettings):
    """Settings wil be read from an .env file"""

    model_config = SettingsConfigDict(env_nested_delimiter="__")

    auth: AuthSettings = AuthSettings()
    resource_providers: list[ResourceProvider] = []
    secret_key: str = "".join(random.choice(string.ascii_letters) for _ in range(16))
    log: bool = False
    insecure: Insecure = Insecure()
    db: DB = DB()
    cors_origins: list[str] = []
    debug_token: bool = False
    show_token: bool = False

    @classmethod
    def settings_customise_sources(
        cls,
        settings_cls: Type[BaseSettings],
        init_settings: PydanticBaseSettingsSource,
        env_settings: PydanticBaseSettingsSource,
        dotenv_settings: PydanticBaseSettingsSource,
        file_secret_settings: PydanticBaseSettingsSource,
    ) -> Tuple[PydanticBaseSettingsSource, ...]:
        return (
            init_settings,
            env_settings,
            file_secret_settings,
            YamlConfigSettingsSource(
                settings_cls,
                Path(
                    Path(
                        environ.get("OIDC_TEST_SETTINGS_FILE", Path.cwd() / "settings.yaml"),
                    )
                ),
            ),
            dotenv_settings,
        )


settings = Settings()