mirror of
https://github.com/hwchase17/langchain
synced 2024-11-06 03:20:49 +00:00
39 lines
1.1 KiB
Python
39 lines
1.1 KiB
Python
from typing import Callable, Union
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from langchain_core.documents import Document
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from langchain_community.docstore.base import Docstore
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class DocstoreFn(Docstore):
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"""Docstore via arbitrary lookup function.
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This is useful when:
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* it's expensive to construct an InMemoryDocstore/dict
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* you retrieve documents from remote sources
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* you just want to reuse existing objects
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"""
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def __init__(
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self,
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lookup_fn: Callable[[str], Union[Document, str]],
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):
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self._lookup_fn = lookup_fn
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def search(self, search: str) -> Document:
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"""Search for a document.
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Args:
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search: search string
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Returns:
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Document if found, else error message.
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"""
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r = self._lookup_fn(search)
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if isinstance(r, str):
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# NOTE: assume the search string is the source ID
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return Document(page_content=r, metadata={"source": search})
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elif isinstance(r, Document):
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return r
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raise ValueError(f"Unexpected type of document {type(r)}")
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