111 lines
3.9 KiB
Python
111 lines
3.9 KiB
Python
"""
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RAG 检索器工厂模块
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提供创建各种检索器的工厂函数，包括：
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- 基础向量检索器
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- ParentDocumentRetriever（父子文档）
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- 混合检索器（稠密+稀疏）
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"""
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from typing import Optional
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from langchain_core.embeddings import Embeddings
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from langchain_core.retrievers import BaseRetriever
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from langchain_classic.retrievers import ParentDocumentRetriever
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from langchain_text_splitters import RecursiveCharacterTextSplitter, TextSplitter
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from langchain_core.stores import BaseStore
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from rag_core import LlamaCppEmbedder, QdrantVectorStore, create_docstore
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def create_parent_retriever(
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collection_name: str = "rag_documents",
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parent_splitter: Optional[TextSplitter] = None,
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child_splitter: Optional[TextSplitter] = None,
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docstore: Optional[BaseStore] = None,
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search_k: int = 5,
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parent_chunk_size: int = 1000,
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parent_chunk_overlap: int = 100,
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child_chunk_size: int = 200,
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child_chunk_overlap: int = 20,
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embeddings: Optional[Embeddings] = None,
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) -> ParentDocumentRetriever:
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"""
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创建 ParentDocumentRetriever 实例（基础稠密向量版本）。
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Args:
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collection_name: Qdrant 集合名称，默认 "rag_documents"
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parent_splitter: 父文档切分器，默认 None（使用默认参数创建）
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child_splitter: 子文档切分器，默认 None（使用默认参数创建）
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docstore: 文档存储实例，默认 None（使用默认参数创建）
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search_k: 检索时返回的结果数，默认 5
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parent_chunk_size: 父文档块大小，默认 1000
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parent_chunk_overlap: 父文档块重叠大小，默认 100
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child_chunk_size: 子文档块大小，默认 200
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child_chunk_overlap: 子文档块重叠大小，默认 20
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embeddings: 嵌入模型实例，默认 None（使用内部默认的 LocalLlamaCppEmbedder）
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Returns:
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ParentDocumentRetriever 实例
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"""
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# 嵌入模型
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if embeddings is None:
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embedder = LlamaCppEmbedder()
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embeddings = embedder.as_langchain_embeddings()
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# 向量存储（只读）
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vector_store = QdrantVectorStore(collection_name=collection_name, embeddings=embeddings)
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# 切分器（若未提供则创建默认）
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if parent_splitter is None:
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parent_splitter = RecursiveCharacterTextSplitter(
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chunk_size=parent_chunk_size,
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chunk_overlap=parent_chunk_overlap,
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)
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if child_splitter is None:
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child_splitter = RecursiveCharacterTextSplitter(
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chunk_size=child_chunk_size,
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chunk_overlap=child_chunk_overlap,
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)
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# 文档存储
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if docstore is None:
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docstore, _ = create_docstore()
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return ParentDocumentRetriever(
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vectorstore=vector_store.get_langchain_vectorstore(),
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docstore=docstore,
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child_splitter=child_splitter,
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parent_splitter=parent_splitter,
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search_kwargs={"k": search_k},
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)
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def create_hybrid_retriever_factory(
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collection_name: str = "rag_documents",
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search_k: int = 5,
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embeddings: Optional[Embeddings] = None,
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) -> BaseRetriever:
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"""
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【不完整，仅占位】创建混合检索器的工厂函数占位符。
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注意：完整的混合检索逻辑在 app/rag/retriever.py 中实现。
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这里仅返回 QdrantVectorStore 作为基础。
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Args:
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collection_name: Qdrant 集合名称
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search_k: 检索返回结果数
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embeddings: 嵌入模型实例
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Returns:
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基础的 QdrantVectorStore（仅稠密检索）
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"""
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# 嵌入模型
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if embeddings is None:
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embedder = LlamaCppEmbedder()
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embeddings = embedder.as_langchain_embeddings()
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# 创建向量存储
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vector_store = QdrantVectorStore(collection_name=collection_name, embeddings=embeddings)
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# 返回 LangChain 兼容的 retriever
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return vector_store.get_langchain_vectorstore().as_retriever(search_kwargs={"k": search_k})
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