Expand requests tool into individual methods for load_tools (#2254)

### Motivation / Context

When exploring `load_tools(["requests"] )`, I would have expected all
request method tools to be imported instead of just `RequestsGetTool`.

### Changes

Break `_get_requests` into multiple functions by request method. Each
function returns the `BaseTool` for that particular request method.

In `load_tools`, if the tool name "requests_all" is encountered, we
replace with all `_BASE_TOOLS` that starts with `requests_`.

This way, `load_tools(["requests"])` returns:
- RequestsGetTool
- RequestsPostTool
- RequestsPatchTool
- RequestsPutTool
- RequestsDeleteTool

langchain/agents/load_tools.py

@@ -1,6 +1,7 @@
 # flake8: noqa
 """Load tools."""
 from typing import Any, List, Optional
+import warnings
 
 from langchain.agents.tools import Tool
 from langchain.callbacks.base import BaseCallbackManager
@@ -16,7 +17,13 @@ from langchain.tools.google_search.tool import GoogleSearchResults, GoogleSearch
 from langchain.tools.searx_search.tool import SearxSearchResults, SearxSearchRun
 from langchain.tools.human.tool import HumanInputRun
 from langchain.tools.python.tool import PythonREPLTool
-from langchain.tools.requests.tool import RequestsGetTool
+from langchain.tools.requests.tool import (
+    RequestsGetTool,
+    RequestsPostTool,
+    RequestsPatchTool,
+    RequestsPutTool,
+    RequestsDeleteTool,
+)
 from langchain.tools.wikipedia.tool import WikipediaQueryRun
 from langchain.tools.wolfram_alpha.tool import WolframAlphaQueryRun
 from langchain.utilities.apify import ApifyWrapper
@@ -34,10 +41,26 @@ def _get_python_repl() -> BaseTool:
     return PythonREPLTool()
 
 
-def _get_requests() -> BaseTool:
+def _get_tools_requests_get() -> BaseTool:
     return RequestsGetTool(requests_wrapper=RequestsWrapper())
 
 
+def _get_tools_requests_post() -> BaseTool:
+    return RequestsPostTool(requests_wrapper=RequestsWrapper())
+
+
+def _get_tools_requests_patch() -> BaseTool:
+    return RequestsPatchTool(requests_wrapper=RequestsWrapper())
+
+
+def _get_tools_requests_put() -> BaseTool:
+    return RequestsPutTool(requests_wrapper=RequestsWrapper())
+
+
+def _get_tools_requests_delete() -> BaseTool:
+    return RequestsDeleteTool(requests_wrapper=RequestsWrapper())
+
+
 def _get_terminal() -> BaseTool:
     return Tool(
         name="Terminal",
@@ -48,7 +71,12 @@ def _get_terminal() -> BaseTool:
 
 _BASE_TOOLS = {
     "python_repl": _get_python_repl,
-    "requests": _get_requests,
+    "requests": _get_tools_requests_get,  # preserved for backwards compatability
+    "requests_get": _get_tools_requests_get,
+    "requests_post": _get_tools_requests_post,
+    "requests_patch": _get_tools_requests_patch,
+    "requests_put": _get_tools_requests_put,
+    "requests_delete": _get_tools_requests_delete,
     "terminal": _get_terminal,
 }
 
@@ -228,8 +256,21 @@ def load_tools(
         List of tools.
     """
     tools = []
+
     for name in tool_names:
-        if name in _BASE_TOOLS:
+        if name == "requests":
+            warnings.warn(
+                "tool name `requests` is deprecated - "
+                "please use `requests_all` or specify the requests method"
+            )
+
+        if name == "requests_all":
+            # expand requests into various methods
+            requests_method_tools = [
+                _tool for _tool in _BASE_TOOLS if _tool.startswith("requests_")
+            ]
+            tool_names.extend(requests_method_tools)
+        elif name in _BASE_TOOLS:
             tools.append(_BASE_TOOLS[name]())
         elif name in _LLM_TOOLS:
             if llm is None: