community: Corrected aload func to be asynchronous from webBaseLoader (#28337)

- **Description:** The aload function, contrary to its name, is not an
asynchronous function, so it cannot work concurrently with other
asynchronous functions.

- **Issue:** #28336 

- **Test: **: Done

- **Docs: **
[here](e0a95e5646/docs/docs/integrations/document_loaders/web_base.ipynb (L201))

- **Lint: ** All checks passed

If no one reviews your PR within a few days, please @-mention one of
baskaryan, efriis, eyurtsev, ccurme, vbarda, hwchase17.

---------

Co-authored-by: Chester Curme <chester.curme@gmail.com>

libs/community/langchain_community/document_loaders/web_base.py

@@ -3,10 +3,11 @@
 import asyncio
 import logging
 import warnings
-from typing import Any, Dict, Iterator, List, Optional, Sequence, Union
+from typing import Any, AsyncIterator, Dict, Iterator, List, Optional, Sequence, Union
 
 import aiohttp
 import requests
+from langchain_core._api import deprecated
 from langchain_core.documents import Document
 
 from langchain_community.document_loaders.base import BaseLoader
@@ -78,12 +79,7 @@ class WebBaseLoader(BaseLoader):
         .. code-block:: python
 
             docs = []
-            docs_lazy = loader.lazy_load()
-
-            # async variant:
-            # docs_lazy = await loader.alazy_load()
-
-            for doc in docs_lazy:
+            for doc in loader.lazy_load():
                 docs.append(doc)
             print(docs[0].page_content[:100])
             print(docs[0].metadata)
@@ -98,7 +94,9 @@ class WebBaseLoader(BaseLoader):
     Async load:
         .. code-block:: python
 
-            docs = await loader.aload()
+            docs = []
+            async for doc in loader.alazy_load():
+                docs.append(doc)
             print(docs[0].page_content[:100])
             print(docs[0].metadata)
 
@@ -108,6 +106,37 @@ class WebBaseLoader(BaseLoader):
 
             {'source': 'https://www.espn.com/', 'title': 'ESPN - Serving Sports Fans. Anytime. Anywhere.', 'description': 'Visit ESPN for live scores, highlights and sports news. Stream exclusive games on ESPN+ and play fantasy sports.', 'language': 'en'}
 
+    .. versionchanged:: 0.3.14
+
+        Deprecated ``aload`` (which was not async) and implemented a native async
+        ``alazy_load``. Expand below for more details.
+
+        .. dropdown:: How to update ``aload``
+
+            Instead of using ``aload``, you can use ``load`` for synchronous loading or
+            ``alazy_load`` for asynchronous lazy loading.
+
+            Example using ``load`` (synchronous):
+
+            .. code-block:: python
+
+                docs: List[Document] = loader.load()
+
+            Example using ``alazy_load`` (asynchronous):
+
+            .. code-block:: python
+
+                docs: List[Document] = []
+                async for doc in loader.alazy_load():
+                    docs.append(doc)
+
+            This is in preparation for accommodating an asynchronous ``aload`` in the
+            future:
+
+            .. code-block:: python
+
+                docs: List[Document] = await loader.aload()
+
     """  # noqa: E501
 
     def __init__(
@@ -279,11 +308,12 @@ class WebBaseLoader(BaseLoader):
                 "`parser` must be one of " + ", ".join(valid_parsers) + "."
             )
 
-    def scrape_all(self, urls: List[str], parser: Union[str, None] = None) -> List[Any]:
-        """Fetch all urls, then return soups for all results."""
+    def _unpack_fetch_results(
+        self, results: Any, urls: List[str], parser: Union[str, None] = None
+    ) -> List[Any]:
+        """Unpack fetch results into BeautifulSoup objects."""
         from bs4 import BeautifulSoup
 
-        results = asyncio.run(self.fetch_all(urls))
         final_results = []
         for i, result in enumerate(results):
             url = urls[i]
@@ -294,9 +324,20 @@ class WebBaseLoader(BaseLoader):
                     parser = self.default_parser
                 self._check_parser(parser)
             final_results.append(BeautifulSoup(result, parser, **self.bs_kwargs))
-
         return final_results
 
+    def scrape_all(self, urls: List[str], parser: Union[str, None] = None) -> List[Any]:
+        """Fetch all urls, then return soups for all results."""
+        results = asyncio.run(self.fetch_all(urls))
+        return self._unpack_fetch_results(results, urls, parser=parser)
+
+    async def ascrape_all(
+        self, urls: List[str], parser: Union[str, None] = None
+    ) -> List[Any]:
+        """Async fetch all urls, then return soups for all results."""
+        results = await self.fetch_all(urls)
+        return self._unpack_fetch_results(results, urls, parser=parser)
+
     def _scrape(
         self,
         url: str,
@@ -339,6 +380,22 @@ class WebBaseLoader(BaseLoader):
             metadata = _build_metadata(soup, path)
             yield Document(page_content=text, metadata=metadata)
 
+    async def alazy_load(self) -> AsyncIterator[Document]:
+        """Async lazy load text from the url(s) in web_path."""
+        results = await self.ascrape_all(self.web_paths)
+        for path, soup in zip(self.web_paths, results):
+            text = soup.get_text(**self.bs_get_text_kwargs)
+            metadata = _build_metadata(soup, path)
+            yield Document(page_content=text, metadata=metadata)
+
+    @deprecated(
+        since="0.3.14",
+        removal="1.0",
+        message=(
+            "See API reference for updated usage: "
+            "https://python.langchain.com/api_reference/community/document_loaders/langchain_community.document_loaders.web_base.WebBaseLoader.html"  # noqa: E501
+        ),
+    )
     def aload(self) -> List[Document]:  # type: ignore
         """Load text from the urls in web_path async into Documents."""
 

libs/community/tests/integration_tests/vectorstores/test_falkordb_vector_integration.py

@@ -102,8 +102,8 @@ def test_falkordbvector() -> None:
         pre_delete_collection=True,
     )
     output = docsearch.similarity_search("foo", k=1)
-    assert type(output) is list
-    assert type(output[0]) is Document
+    assert isinstance(output, list)
+    assert isinstance(output[0], Document)
     assert output[0].page_content == "foo"
 
     drop_vector_indexes(docsearch)
@@ -121,8 +121,8 @@ def test_falkordbvector_embeddings() -> None:
         pre_delete_collection=True,
     )
     output = docsearch.similarity_search("foo", k=1)
-    assert type(output) is list
-    assert type(output[0]) is Document
+    assert isinstance(output, list)
+    assert isinstance(output[0], Document)
     assert output[0].page_content == "foo"
 
     drop_vector_indexes(docsearch)
@@ -168,8 +168,8 @@ def test_falkordbvector_with_metadatas() -> None:
         pre_delete_collection=True,
     )
     output = docsearch.similarity_search("foo", k=1)
-    assert type(output) is list
-    assert type(output[0]) is Document
+    assert isinstance(output, list)
+    assert isinstance(output[0], Document)
     assert output[0].metadata.get("page") == "0"
 
     drop_vector_indexes(docsearch)

libs/community/tests/unit_tests/document_loaders/test_web_base.py

@@ -62,6 +62,52 @@ def test_lazy_load(mock_get: Any) -> None:
     assert results[0].page_content == "This is a div with a special class"
 
 
+@pytest.mark.requires("bs4")
+@patch("aiohttp.ClientSession.get")
+async def test_alazy_load(mock_get: Any) -> None:
+    async def mock_text() -> str:
+        return "<html><body><p>Test content</p></body></html>"
+
+    import bs4
+
+    mock_response = MagicMock()
+    mock_response.text = mock_text
+    mock_get.return_value.__aenter__.return_value = mock_response
+
+    loader = WebBaseLoader(web_paths=["https://www.example.com"])
+    results = []
+    async for result in loader.alazy_load():
+        results.append(result)
+    # mock_get.assert_called_with("https://www.example.com")
+    assert len(results) == 1
+    assert results[0].page_content == "Test content"
+
+    # Test bs4 kwargs
+    async def mock_text_bs4() -> str:
+        return dedent("""
+            <html>
+            <body>
+                <p>Test content</p>
+                <div class="special-class">This is a div with a special class</div>
+            </body>
+            </html>
+            """)
+
+    mock_response = MagicMock()
+    mock_response.text = mock_text_bs4
+    mock_get.return_value.__aenter__.return_value = mock_response
+
+    loader = WebBaseLoader(
+        web_paths=["https://www.example.com"],
+        bs_kwargs={"parse_only": bs4.SoupStrainer(class_="special-class")},
+    )
+    results = []
+    async for result in loader.alazy_load():
+        results.append(result)
+    assert len(results) == 1
+    assert results[0].page_content == "This is a div with a special class"
+
+
 @pytest.mark.requires("bs4")
 @patch("aiohttp.ClientSession.get")
 def test_aload(mock_get: Any) -> None: