feat: enhance dataset file fetching with improved pagination and document loading support (#156)

runtime/datamate-python/app/common/document_loaders.py

@@ -0,0 +1,93 @@
+from typing import List, Union, Optional
+from pathlib import Path
+
+from langchain_core.documents import Document
+from langchain_community.document_loaders import (
+    TextLoader,
+    JSONLoader,
+    CSVLoader,
+    UnstructuredMarkdownLoader,
+    PyPDFLoader,
+    Docx2txtLoader
+)
+
+from app.core.logging import get_logger
+
+log = get_logger(__name__)
+
+class UniversalDocLoader:
+    """
+    通用泛文本文档加载类
+    支持格式：TXT/JSON/CSV/Markdown/Word(.docx)/PPT(.pptx)/PDF
+    """
+    # 格式-加载器映射（轻量优先）
+    SUPPORTED_FORMATS = {
+        # 纯文本类
+        ".txt": TextLoader,
+        ".json": JSONLoader,
+        ".csv": CSVLoader,
+        ".md": UnstructuredMarkdownLoader,
+        # 办公文档类
+        ".docx": Docx2txtLoader,
+        ".doc": Docx2txtLoader,
+        # PDF 类
+        ".pdf": PyPDFLoader
+    }
+
+    def __init__(self, file_path: Union[str, Path]):
+        self.file_path = Path(file_path).resolve()
+        self.file_suffix = self.file_path.suffix.lower()
+        log.info(f"初始化文档加载器: {self.file_path} (格式: {self.file_suffix})")
+        self._validate_file()
+
+    def _validate_file(self) -> None:
+        """验证文件存在性和格式支持性"""
+        if not self.file_path.exists():
+            raise FileNotFoundError(f"文件不存在: {self.file_path}")
+        if self.file_suffix not in self.SUPPORTED_FORMATS:
+            raise ValueError(
+                f"不支持的格式: {self.file_suffix} | 支持格式: {list(self.SUPPORTED_FORMATS.keys())}"
+            )
+
+    def load(
+        self,
+        file_format: Optional[str] = None,
+        **loader_kwargs
+    ) -> List[Document]:
+        """
+        加载文档并返回 LangChain Document 列表
+        :param file_format: 手动指定格式（如 ".pdf"），默认自动识别
+        :param loader_kwargs: 传递给具体加载器的参数（如 JSONLoader 的 jq_schema）
+        :return: List[Document]
+        """
+        # 确定目标格式
+        target_format = file_format.lower() if file_format else self.file_suffix
+        loader_cls = self.SUPPORTED_FORMATS[target_format]
+
+        # 加载器默认参数优化
+        loader_kwargs = self._set_default_kwargs(loader_cls, loader_kwargs)
+
+        # 初始化并加载
+        loader = loader_cls(str(self.file_path), **loader_kwargs)
+        return loader.load()
+
+    @staticmethod
+    def _set_default_kwargs(loader_cls, kwargs: dict) -> dict:
+        """为不同加载器设置默认参数，简化调用"""
+        if loader_cls == JSONLoader and "jq_schema" not in kwargs:
+            kwargs.setdefault("jq_schema", ".")
+            kwargs.setdefault("text_content", False)
+        if loader_cls == CSVLoader and "csv_args" not in kwargs:
+            kwargs["csv_args"] = {"delimiter": ","}
+        return kwargs
+
+
+# 文档加载器便捷函数
+def load_documents(
+    file_path: Union[str, Path],
+    file_format: Optional[str] = None,
+    **loader_kwargs
+) -> List[Document]:
+    """快速加载文档的便捷函数"""
+    loader = UniversalDocLoader(file_path)
+    return loader.load(file_format=file_format, **loader_kwargs)