dify/api/core/rerank/rerank.py

from typing import List, Optional

from langchain.schema import Document

from core.model_manager import ModelInstance


class RerankRunner:
    def __init__(self, rerank_model_instance: ModelInstance) -> None:
        self.rerank_model_instance = rerank_model_instance

    def run(self, query: str, documents: List[Document], score_threshold: Optional[float] = None,
            top_n: Optional[int] = None, user: Optional[str] = None) -> List[Document]:
        """
        Run rerank model
        :param query: search query
        :param documents: documents for reranking
        :param score_threshold: score threshold
        :param top_n: top n
        :param user: unique user id if needed
        :return:
        """
        docs = []
        doc_id = []
        unique_documents = []
        for document in documents:
            if document.metadata['doc_id'] not in doc_id:
                doc_id.append(document.metadata['doc_id'])
                docs.append(document.page_content)
                unique_documents.append(document)

        documents = unique_documents

        rerank_result = self.rerank_model_instance.invoke_rerank(
            query=query,
            docs=docs,
            score_threshold=score_threshold,
            top_n=top_n,
            user=user
        )

        rerank_documents = []

        for result in rerank_result.docs:
            # format document
            rerank_document = Document(
                page_content=result.text,
                metadata={
                    "doc_id": documents[result.index].metadata['doc_id'],
                    "doc_hash": documents[result.index].metadata['doc_hash'],
                    "document_id": documents[result.index].metadata['document_id'],
                    "dataset_id": documents[result.index].metadata['dataset_id'],
                    'score': result.score
                }
            )
            rerank_documents.append(rerank_document)

        return rerank_documents