Source code for requests_cache.backends.gridfs

"""
.. image::
    ../_static/mongodb.png

`GridFS <https://docs.mongodb.com/manual/core/gridfs/>`_ is a specification for storing large files
(>16 MB) in MongoDB. See :py:mod:`~requests_cache.backends.mongodb` for more general info on MongoDB.

API Reference
^^^^^^^^^^^^^
.. automodsumm:: requests_cache.backends.gridfs
   :classes-only:
   :nosignatures:
"""
from logging import getLogger
from threading import RLock

from gridfs import GridFS
from gridfs.errors import CorruptGridFile, FileExists
from pymongo import MongoClient

from .._utils import get_valid_kwargs
from .base import BaseCache, BaseStorage
from .mongodb import MongoDict

logger = getLogger(__name__)


[docs]class GridFSCache(BaseCache): """GridFS cache backend. Example: >>> session = CachedSession('http_cache', backend='gridfs') Args: db_name: Database name connection: :py:class:`pymongo.MongoClient` object to reuse instead of creating a new one kwargs: Additional keyword arguments for :py:class:`pymongo.MongoClient` """ def __init__(self, db_name: str, **kwargs): super().__init__(**kwargs) self.responses = GridFSPickleDict(db_name, **kwargs) self.redirects = MongoDict( db_name, collection_name='redirects', connection=self.responses.connection, **kwargs )
[docs] def remove_expired_responses(self, *args, **kwargs): with self.responses._lock: return super().remove_expired_responses(*args, **kwargs)
[docs]class GridFSPickleDict(BaseStorage): """A dictionary-like interface for a GridFS database Args: db_name: Database name collection_name: Ignored; GridFS internally uses collections 'fs.files' and 'fs.chunks' connection: :py:class:`pymongo.MongoClient` object to reuse instead of creating a new one kwargs: Additional keyword arguments for :py:class:`pymongo.MongoClient` """ def __init__(self, db_name, collection_name=None, connection=None, **kwargs): super().__init__(**kwargs) connection_kwargs = get_valid_kwargs(MongoClient, kwargs) self.connection = connection or MongoClient(**connection_kwargs) self.db = self.connection[db_name] self.fs = GridFS(self.db) self._lock = RLock() def __getitem__(self, key): try: with self._lock: result = self.fs.find_one({'_id': key}) if result is None: raise KeyError return self.serializer.loads(result.read()) except CorruptGridFile as e: logger.warning(e, exc_info=True) raise KeyError def __setitem__(self, key, item): value = self.serializer.dumps(item) encoding = None if isinstance(value, bytes) else 'utf-8' with self._lock: try: self.fs.delete(key) self.fs.put(value, encoding=encoding, **{'_id': key}) # This can happen because GridFS is not thread-safe for concurrent writes except FileExists as e: logger.warning(e, exc_info=True) def __delitem__(self, key): with self._lock: res = self.fs.find_one({'_id': key}) if res is None: raise KeyError self.fs.delete(res._id) def __len__(self): return self.db['fs.files'].estimated_document_count() def __iter__(self): for d in self.fs.find(): yield d._id
[docs] def clear(self): self.db['fs.files'].drop() self.db['fs.chunks'].drop()