from typing import Iterable
from pymongo import MongoClient
from . import BaseCache, BaseStorage, get_valid_kwargs
[docs]class MongoCache(BaseCache):
"""MongoDB cache backend
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 = 'http_cache', connection: MongoClient = None, **kwargs):
super().__init__(**kwargs)
self.responses = MongoPickleDict(db_name, 'responses', connection=connection, **kwargs)
self.redirects = MongoDict(
db_name,
collection_name='redirects',
connection=self.responses.connection,
**kwargs,
)
[docs]class MongoDict(BaseStorage):
"""A dictionary-like interface for a MongoDB collection
Args:
db_name: Database name
collection_name: Collection 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, collection_name='http_cache', connection=None, **kwargs):
super().__init__(**kwargs)
connection_kwargs = get_valid_kwargs(MongoClient, kwargs)
self.connection = connection or MongoClient(**connection_kwargs)
self.collection = self.connection[db_name][collection_name]
def __getitem__(self, key):
result = self.collection.find_one({'_id': key})
if result is None:
raise KeyError
return result['data']
def __setitem__(self, key, item):
doc = {'_id': key, 'data': item}
self.collection.replace_one({'_id': key}, doc, upsert=True)
def __delitem__(self, key):
result = self.collection.find_one_and_delete({'_id': key}, {'_id': True})
if result is None:
raise KeyError
def __len__(self):
return self.collection.estimated_document_count()
def __iter__(self):
for d in self.collection.find({}, {'_id': True}):
yield d['_id']
[docs] def bulk_delete(self, keys: Iterable[str]):
"""Delete multiple keys from the cache. Does not raise errors for missing keys."""
self.collection.delete_many({'_id': {'$in': list(keys)}})
[docs] def clear(self):
self.collection.drop()
[docs]class MongoPickleDict(MongoDict):
"""Same as :class:`MongoDict`, but pickles values before saving"""
def __setitem__(self, key, item):
super().__setitem__(key, self.serializer.dumps(item))
def __getitem__(self, key):
return self.serializer.loads(super().__getitem__(key))