Source code for langchain.storage.in_memory
"""In memory store that is not thread safe and has no eviction policy.
This is a simple implementation of the BaseStore using a dictionary that is useful
primarily for unit testing purposes.
"""
from typing import (
Any,
Dict,
Generic,
Iterator,
List,
Optional,
Sequence,
Tuple,
TypeVar,
)
from langchain_core.stores import BaseStore
V = TypeVar("V")
[docs]class InMemoryBaseStore(BaseStore[str, V], Generic[V]):
"""In-memory implementation of the BaseStore using a dictionary.
Attributes:
store (Dict[str, Any]): The underlying dictionary that stores
the key-value pairs.
Examples:
.. code-block:: python
from langchain.storage import InMemoryStore
store = InMemoryStore()
store.mset([('key1', 'value1'), ('key2', 'value2')])
store.mget(['key1', 'key2'])
# ['value1', 'value2']
store.mdelete(['key1'])
list(store.yield_keys())
# ['key2']
list(store.yield_keys(prefix='k'))
# ['key2']
"""
[docs] def __init__(self) -> None:
"""Initialize an empty store."""
self.store: Dict[str, V] = {}
[docs] def mget(self, keys: Sequence[str]) -> List[Optional[V]]:
"""Get the values associated with the given keys.
Args:
keys (Sequence[str]): A sequence of keys.
Returns:
A sequence of optional values associated with the keys.
If a key is not found, the corresponding value will be None.
"""
return [self.store.get(key) for key in keys]
[docs] def mset(self, key_value_pairs: Sequence[Tuple[str, V]]) -> None:
"""Set the values for the given keys.
Args:
key_value_pairs (Sequence[Tuple[str, V]]): A sequence of key-value pairs.
Returns:
None
"""
for key, value in key_value_pairs:
self.store[key] = value
[docs] def mdelete(self, keys: Sequence[str]) -> None:
"""Delete the given keys and their associated values.
Args:
keys (Sequence[str]): A sequence of keys to delete.
"""
for key in keys:
if key in self.store:
del self.store[key]
[docs] def yield_keys(self, prefix: Optional[str] = None) -> Iterator[str]:
"""Get an iterator over keys that match the given prefix.
Args:
prefix (str, optional): The prefix to match. Defaults to None.
Returns:
Iterator[str]: An iterator over keys that match the given prefix.
"""
if prefix is None:
yield from self.store.keys()
else:
for key in self.store.keys():
if key.startswith(prefix):
yield key
InMemoryStore = InMemoryBaseStore[Any]
InMemoryByteStore = InMemoryBaseStore[bytes]