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Version: 2.20-unstable

Caching

Module cache_checker​

CacheChecker​

Checks for the presence of documents in a Document Store based on a specified field in each document's metadata.

If matching documents are found, they are returned as "hits". If not found in the cache, the items are returned as "misses".

Usage example​

python
from haystack import Document
from haystack.document_stores.in_memory import InMemoryDocumentStore
from haystack.components.caching.cache_checker import CacheChecker

docstore = InMemoryDocumentStore()
documents = [
    Document(content="doc1", meta={"url": "https://example.com/1"}),
    Document(content="doc2", meta={"url": "https://example.com/2"}),
    Document(content="doc3", meta={"url": "https://example.com/1"}),
    Document(content="doc4", meta={"url": "https://example.com/2"}),
]
docstore.write_documents(documents)
checker = CacheChecker(docstore, cache_field="url")
results = checker.run(items=["https://example.com/1", "https://example.com/5"])
assert results == {"hits": [documents[0], documents[2]], "misses": ["https://example.com/5"]}

CacheChecker.__init__​

python
def __init__(document_store: DocumentStore, cache_field: str)

Creates a CacheChecker component.

Arguments:

  • document_store: Document Store to check for the presence of specific documents.
  • cache_field: Name of the document's metadata field to check for cache hits.

CacheChecker.to_dict​

python
def to_dict() -> dict[str, Any]

Serializes the component to a dictionary.

Returns:

Dictionary with serialized data.

CacheChecker.from_dict​

python
@classmethod
def from_dict(cls, data: dict[str, Any]) -> "CacheChecker"

Deserializes the component from a dictionary.

Arguments:

  • data: Dictionary to deserialize from.

Returns:

Deserialized component.

CacheChecker.run​

python
@component.output_types(hits=list[Document], misses=list)
def run(items: list[Any])

Checks if any document associated with the specified cache field is already present in the store.

Arguments:

  • items: Values to be checked against the cache field.

Returns:

A dictionary with two keys:

  • hits - Documents that matched with at least one of the items.
  • misses - Items that were not present in any documents.