community[patch]: Adding HEADER to the list of supported locations (#21946)

**Description:** adds headers to the list of supported locations when
generating the openai function schema

libs/community/langchain_community/tools/openapi/utils/api_models.py

@@ -55,6 +55,7 @@ class APIPropertyLocation(Enum):
 _SUPPORTED_MEDIA_TYPES = ("application/json",)
 
 SUPPORTED_LOCATIONS = {
+    APIPropertyLocation.HEADER,
     APIPropertyLocation.QUERY,
     APIPropertyLocation.PATH,
 }

libs/community/tests/unit_tests/data/openapi_specs/openapi_spec_header_param.json

@@ -0,0 +1,34 @@
+{
+    "openapi": "3.0.0",
+    "info": {
+      "version": "1.0.0",
+      "title": "Swagger Petstore",
+      "license": {
+        "name": "MIT"
+      }
+    },
+    "servers": [
+      {
+        "url": "http://petstore.swagger.io/v1"
+      }
+    ],
+    "paths": {
+      "/pets": {
+        "get": {
+          "summary": "Info for a specific pet",
+          "operationId": "showPetById",
+          "parameters": [
+            {
+              "name": "header_param",
+              "in": "header",
+              "required": true,
+              "description": "A header param",
+              "schema": {
+                "type": "string"
+              }
+            }
+          ]
+        }
+      }
+    }
+  }

libs/community/tests/unit_tests/utilities/test_openapi.py

@@ -0,0 +1,44 @@
+from pathlib import Path
+
+import pytest
+from langchain.chains.openai_functions.openapi import openapi_spec_to_openai_fn
+
+from langchain_community.utilities.openapi import (  # noqa: E402 # ignore: community-import
+    OpenAPISpec,
+)
+
+EXPECTED_OPENAI_FUNCTIONS_HEADER_PARAM = [
+    {
+        "name": "showPetById",
+        "description": "Info for a specific pet",
+        "parameters": {
+            "type": "object",
+            "properties": {
+                "headers": {
+                    "type": "object",
+                    "properties": {
+                        "header_param": {
+                            "type": "string",
+                            "description": "A header param",
+                        }
+                    },
+                    "required": ["header_param"],
+                }
+            },
+        },
+    }
+]
+
+
+@pytest.mark.requires("openapi_pydantic")
+def test_header_param() -> None:
+    spec = OpenAPISpec.from_file(
+        Path(__file__).parent.parent
+        / "data"
+        / "openapi_specs"
+        / "openapi_spec_header_param.json",
+    )
+
+    openai_functions, _ = openapi_spec_to_openai_fn(spec)
+
+    assert openai_functions == EXPECTED_OPENAI_FUNCTIONS_HEADER_PARAM