fimfarchive/fimfarchive/stories.py
2018-09-15 17:56:39 +02:00

147 lines
3.8 KiB
Python

"""
Stories for Fimfarchive.
"""
#
# Fimfarchive, preserves stories from Fimfiction.
# Copyright (C) 2018 Joakim Soderlund
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
from typing import TYPE_CHECKING, Any, Dict, Iterable, TypeVar
from fimfarchive.exceptions import StorySourceError
if TYPE_CHECKING:
from fimfarchive.fetchers import Fetcher
from fimfarchive.flavors import Flavor
else:
Fetcher = TypeVar('Fetcher')
Flavor = TypeVar('Flavor')
__all__ = (
'Story',
)
class Story:
"""
Represents a story.
"""
def __init__(
self,
key: int,
fetcher: Fetcher = None,
meta: Dict[str, Any] = None,
data: bytes = None,
flavors: Iterable[Flavor] = (),
) -> None:
"""
Constructor.
Args:
key: Primary key of the story.
fetcher: Fetcher to use for lazy fetching.
meta: Meta to populate the story with.
data: Data to populate the story with.
flavors: Content type hints.
"""
if fetcher is None and (data is None or meta is None):
raise ValueError("Story must contain fetcher if lazy.")
self.key = key
self.fetcher = fetcher
self.flavors = set(flavors)
self._meta = meta
self._data = data
@property
def is_fetched(self) -> bool:
"""
True if no more fetches are necessary.
"""
return self.has_meta and self.has_data
@property
def has_meta(self) -> bool:
"""
True if story meta has been fetched.
"""
return self._meta is not None
@property
def meta(self) -> Dict[str, Any]:
"""
Returns the story meta.
Meta may be fetched if this story instance is lazy.
Raises:
InvalidStoryError: If a valid story is not found.
StorySourceError: If source does not return any data.
"""
if self._meta is None and self.fetcher:
self._meta = self.fetcher.fetch_meta(self.key)
if self._meta is None:
raise StorySourceError("Meta is missing.")
return self._meta
@property
def has_data(self) -> bool:
"""
True if story data has been fetched.
"""
return self._data is not None
@property
def data(self) -> bytes:
"""
Returns the story data.
Data may be fetched if this story instance is lazy.
Raises:
InvalidStoryError: If a valid story is not found.
StorySourceError: If source does not return any data.
"""
if self._data is None and self.fetcher:
self._data = self.fetcher.fetch_data(self.key)
if self._data is None:
raise StorySourceError("Data is missing.")
return self._data
def merge(self, **params) -> 'Story':
"""
Returns a shallow copy, optionally replacing attributes.
Args:
**params: Overrides parameters from the current instance.
Raises:
TypeError: If passed an unexpected parameter.
"""
kwargs = {k.lstrip('_'): v for k, v in vars(self).items()}
kwargs.update(params)
return type(self)(**kwargs)