Adding File-Like object support in CSV Agent Toolkit (#10409)

If loading a CSV from a direct or temporary source, loading the
file-like object (subclass of IOBase) directly allows the agent creation
process to succeed, instead of throwing a ValueError.

Added an additional elif and tweaked value error message.
Added test to validate this functionality.

Pandas from_csv supports this natively but this current implementation
only accepts strings or paths to files.
https://pandas.pydata.org/docs/user_guide/io.html#io-read-csv-table

---------

Co-authored-by: Harrison Chase <hw.chase.17@gmail.com>
Co-authored-by: Bagatur <baskaryan@gmail.com>

libs/langchain/langchain/agents/agent_toolkits/csv/base.py

@@ -1,3 +1,4 @@
+from io import IOBase
 from typing import Any, List, Optional, Union
 
 from langchain.agents.agent import AgentExecutor
@@ -7,7 +8,7 @@ from langchain.schema.language_model import BaseLanguageModel
 
 def create_csv_agent(
     llm: BaseLanguageModel,
-    path: Union[str, List[str]],
+    path: Union[str, IOBase, List[Union[str, IOBase]]],
     pandas_kwargs: Optional[dict] = None,
     **kwargs: Any,
 ) -> AgentExecutor:
@@ -20,14 +21,14 @@ def create_csv_agent(
         )
 
     _kwargs = pandas_kwargs or {}
-    if isinstance(path, str):
+    if isinstance(path, (str, IOBase)):
         df = pd.read_csv(path, **_kwargs)
     elif isinstance(path, list):
         df = []
         for item in path:
-            if not isinstance(item, str):
-                raise ValueError(f"Expected str, got {type(path)}")
+            if not isinstance(item, (str, IOBase)):
+                raise ValueError(f"Expected str or file-like object, got {type(path)}")
             df.append(pd.read_csv(item, **_kwargs))
     else:
-        raise ValueError(f"Expected str or list, got {type(path)}")
+        raise ValueError(f"Expected str, list, or file-like object, got {type(path)}")
     return create_pandas_dataframe_agent(llm, df, **kwargs)

libs/langchain/tests/integration_tests/agent/test_csv_agent.py

@@ -1,3 +1,4 @@
+import io
 import re
 
 import numpy as np
@@ -34,6 +35,15 @@ def csv_list(tmp_path_factory: TempPathFactory) -> DataFrame:
     return [filename1, filename2]
 
 
+@pytest.fixture(scope="module")
+def csv_file_like(tmp_path_factory: TempPathFactory) -> io.BytesIO:
+    random_data = np.random.rand(4, 4)
+    df = DataFrame(random_data, columns=["name", "age", "food", "sport"])
+    buffer = io.BytesIO()
+    df.to_pickle(buffer)
+    return buffer
+
+
 def test_csv_agent_creation(csv: str) -> None:
     agent = create_csv_agent(OpenAI(temperature=0), csv)
     assert isinstance(agent, AgentExecutor)
@@ -55,3 +65,12 @@ def test_multi_csv(csv_list: list) -> None:
     result = re.search(r".*(6).*", response)
     assert result is not None
     assert result.group(1) is not None
+
+
+def test_file_like(file_like: io.BytesIO) -> None:
+    agent = create_csv_agent(OpenAI(temperature=0), file_like, verbose=True)
+    assert isinstance(agent, AgentExecutor)
+    response = agent.run("How many rows in the csv? Give me a number.")
+    result = re.search(r".*(4).*", response)
+    assert result is not None
+    assert result.group(1) is not None