langchain_community.docstore.arbitrary_fn

from typing import Callable, Union

from langchain_core.documents import Document

from langchain_community.docstore.base import Docstore


[docs]class DocstoreFn(Docstore):
    """通过任意查找函数进行文档存储。

    当以下情况时，这将非常有用：
     * 构建InMemoryDocstore/dict的成本很高
     * 从远程源检索文档
     * 想要重用现有对象"""

[docs]    def __init__(
        self,
        lookup_fn: Callable[[str], Union[Document, str]],
    ):
        self._lookup_fn = lookup_fn

[docs]    def search(self, search: str) -> Document:
        """搜索文档。

参数：
    search: 搜索字符串

返回：
    如果找到文档，则返回文档，否则返回错误消息。
"""
        r = self._lookup_fn(search)
        if isinstance(r, str):
            # NOTE: assume the search string is the source ID
            return Document(page_content=r, metadata={"source": search})
        elif isinstance(r, Document):
            return r
        raise ValueError(f"Unexpected type of document {type(r)}")
Source code for langchain_community.docstore.arbitrary_fn
