from abc import abstractmethod
from collections.abc import Iterable
from typing import Generic
from ..offline.types import PlaceholderAttributes, SourcePlaceholderTranslations
from ..types import HasSources, IdType, SourceType
from .types import IdsToFetch
[docs]
class Fetcher(Generic[SourceType, IdType], HasSources[SourceType]):
"""Interface for fetching translations from an external source."""
[docs]
@abstractmethod
def initialize_sources(self, task_id: int | None = None, *, force: bool = False) -> None:
"""Perform source discovery.
Args:
task_id: Used for logging.
force: If ``True``, perform full discovery even if sources are already known.
See Also:
🔑 This is a key event method. See :ref:`key-events` for details.
Notes:
This function is called implicitly before every translation task. Result should be cached.
"""
@property
@abstractmethod
def allow_fetch_all(self) -> bool:
"""Flag indicating whether the :meth:`~.fetching.Fetcher.fetch_all` operation is permitted."""
[docs]
def close(self) -> None:
"""Close the ``Fetcher``. Does nothing by default."""
@property
@abstractmethod
def online(self) -> bool:
"""Return connectivity status. If ``False``, no new translations may be fetched."""
@property
def optional(self) -> bool:
"""Return ``True`` if this fetcher has been marked as `optional`.
In multi-fetcher mode, optional fetchers may be discarded if :attr:`~.HasSources.sources` cannot be resolved
(raises an exception). Default value is ``False``.
Returns:
Optionality status.
"""
return False
[docs]
@abstractmethod
def fetch(
self,
ids_to_fetch: Iterable[IdsToFetch[SourceType, IdType]],
placeholders: Iterable[str] = (),
*,
required: Iterable[str] = (),
placeholder_attributes: PlaceholderAttributes | None = None,
task_id: int | None = None,
enable_uuid_heuristics: bool = False,
) -> SourcePlaceholderTranslations[SourceType]:
"""Retrieve placeholder translations from the source.
Args:
ids_to_fetch: An iterable of :class:`.IdsToFetch`.
placeholders: All desired placeholders in preferred order.
required: Placeholders that must be included in the response.
placeholder_attributes: Attributes that will be accessed for each placeholder.
task_id: Used for logging.
enable_uuid_heuristics: Improves matching when :py:class:`~uuid.UUID`-like IDs are in use.
Returns:
A mapping ``{source: PlaceholderTranslations}`` of translation elements.
Raises:
UnknownPlaceholderError: For placeholder(s) that are unknown to the ``Fetcher``.
UnknownSourceError: For sources(s) that are unknown to the ``Fetcher``.
ForbiddenOperationError: If trying to fetch all IDs when not possible or permitted.
ImplementationError: For errors made by the inheriting implementation.
See Also:
🔑 This is a key event method. See :ref:`key-events` for details.
Notes:
Placeholders are usually columns in relational database applications. These are the components which are
combined to create ID translations. See :class:`~id_translation.offline.Format` documentation for details.
"""
[docs]
@abstractmethod
def fetch_all(
self,
placeholders: Iterable[str] = (),
*,
required: Iterable[str] = (),
placeholder_attributes: PlaceholderAttributes | None = None,
sources: set[SourceType] | None = None,
task_id: int | None = None,
enable_uuid_heuristics: bool = False,
) -> SourcePlaceholderTranslations[SourceType]:
"""Fetch as much data as possible.
Args:
placeholders: All desired placeholders in preferred order.
required: Placeholders that must be included in the response.
placeholder_attributes: Attributes that will be accessed for each placeholder.
sources: A subset of sources to fetch. Unknown sources are ignored. Set to ``None`` to fetch all sources.
task_id: Used for logging.
enable_uuid_heuristics: Improves matching when :py:class:`~uuid.UUID`-like IDs are in use.
Returns:
A mapping ``{source: PlaceholderTranslations}`` of translation elements.
See Also:
🔑 This is a key event method. See :ref:`key-events` for details.
Raises:
ForbiddenOperationError: If fetching all IDs is not possible or permitted.
UnknownPlaceholderError: For placeholder(s) that are unknown to the ``Fetcher``.
ImplementationError: For errors made by the inheriting implementation.
"""
