core[minor]: move document compressor base (#17910)

libs/core/langchain_core/documents/__init__.py

@@ -3,6 +3,7 @@ and their transformations.
 
 """
 from langchain_core.documents.base import Document
+from langchain_core.documents.compressor import BaseDocumentCompressor
 from langchain_core.documents.transformers import BaseDocumentTransformer
 
-__all__ = ["Document", "BaseDocumentTransformer"]
+__all__ = ["Document", "BaseDocumentTransformer", "BaseDocumentCompressor"]

libs/core/langchain_core/documents/compressor.py

@@ -0,0 +1,33 @@
+from __future__ import annotations
+
+from abc import ABC, abstractmethod
+from typing import Optional, Sequence
+
+from langchain_core.callbacks import Callbacks
+from langchain_core.documents import Document
+from langchain_core.pydantic_v1 import BaseModel
+from langchain_core.runnables import run_in_executor
+
+
+class BaseDocumentCompressor(BaseModel, ABC):
+    """Base class for document compressors."""
+
+    @abstractmethod
+    def compress_documents(
+        self,
+        documents: Sequence[Document],
+        query: str,
+        callbacks: Optional[Callbacks] = None,
+    ) -> Sequence[Document]:
+        """Compress retrieved documents given the query context."""
+
+    async def acompress_documents(
+        self,
+        documents: Sequence[Document],
+        query: str,
+        callbacks: Optional[Callbacks] = None,
+    ) -> Sequence[Document]:
+        """Compress retrieved documents given the query context."""
+        return await run_in_executor(
+            None, self.compress_documents, documents, query, callbacks
+        )