Bos loader (#11525)

**Description:**
Add  BaiduCloud BOS document loader.

---------

Co-authored-by: chenweixu01 <chenweixu01@baidu.com>
Co-authored-by: root <root@icoding-cwx.bcc-szzj.baidu.com>
Co-authored-by: Bagatur <baskaryan@gmail.com>

libs/langchain/langchain/document_loaders/baiducloud_bos_directory.py

@@ -0,0 +1,52 @@
+from typing import Any, Iterator, List
+
+from langchain.docstore.document import Document
+from langchain.document_loaders.base import BaseLoader
+
+
+class BaiduBOSDirectoryLoader(BaseLoader):
+    """Load from `Baidu BOS directory`."""
+
+    def __init__(self, conf: Any, bucket: str, prefix: str = ""):
+        """Initialize with BOS config, bucket and prefix.
+        :param conf(BosConfig): BOS config.
+        :param bucket(str): BOS bucket.
+        :param prefix(str): prefix.
+        """
+        self.conf = conf
+        self.bucket = bucket
+        self.prefix = prefix
+
+    def load(self) -> List[Document]:
+        return list(self.lazy_load())
+
+    def lazy_load(self) -> Iterator[Document]:
+        """Load documents."""
+        try:
+            from baidubce.services.bos.bos_client import BosClient
+        except ImportError:
+            raise ImportError(
+                "Please install bce-python-sdk with `pip install bce-python-sdk`."
+            )
+        client = BosClient(self.conf)
+        contents = []
+        marker = ""
+        while True:
+            response = client.list_objects(
+                bucket_name=self.bucket,
+                prefix=self.prefix,
+                marker=marker,
+                max_keys=1000,
+            )
+            contents_len = len(response.contents)
+            contents.extend(response.contents)
+            if response.is_truncated or contents_len < int(str(response.max_keys)):
+                break
+            marker = response.next_marker
+        from baidu_bos_file import BaiduBOSFileLoader
+
+        for content in contents:
+            if str(content.key).endswith("/"):
+                continue
+            loader = BaiduBOSFileLoader(self.conf, self.bucket, str(content.key))
+            yield loader.load()[0]

libs/langchain/langchain/document_loaders/baiducloud_bos_file.py

@@ -0,0 +1,53 @@
+import logging
+import os
+import tempfile
+from typing import Any, Iterator, List
+
+from langchain.docstore.document import Document
+from langchain.document_loaders.base import BaseLoader
+from langchain.document_loaders.unstructured import UnstructuredFileLoader
+
+logger = logging.getLogger(__name__)
+
+
+class BaiduBOSFileLoader(BaseLoader):
+    """Load from `Baidu Cloud BOS` file."""
+
+    def __init__(self, conf: Any, bucket: str, key: str):
+        """Initialize with BOS config, bucket and key name.
+        :param conf(BceClientConfiguration): BOS config.
+        :param bucket(str): BOS bucket.
+        :param key(str): BOS file key.
+        """
+        self.conf = conf
+        self.bucket = bucket
+        self.key = key
+
+    def load(self) -> List[Document]:
+        return list(self.lazy_load())
+
+    def lazy_load(self) -> Iterator[Document]:
+        """Load documents."""
+        try:
+            from baidubce.services.bos.bos_client import BosClient
+        except ImportError:
+            raise ImportError(
+                "Please using `pip install bce-python-sdk`"
+                + " before import bos related package."
+            )
+
+        # Initialize BOS Client
+        client = BosClient(self.conf)
+        with tempfile.TemporaryDirectory() as temp_dir:
+            file_path = f"{temp_dir}/{self.bucket}/{self.key}"
+            os.makedirs(os.path.dirname(file_path), exist_ok=True)
+            # Download the file to a destination
+            logger.debug(f"get object key {self.key} to file {file_path}")
+            client.get_object_to_file(self.bucket, self.key, file_path)
+            try:
+                loader = UnstructuredFileLoader(file_path)
+                documents = loader.load()
+                return iter(documents)
+            except Exception as ex:
+                logger.error(f"load document error = {ex}")
+                return iter([Document(page_content="")])