(Bug fix) - allow using Assistants GET, DELETE on /openai pass through routes (#8818)

* test_openai_assistants_e2e_operations

* test openai assistants pass through

* fix GET request on pass through handler

* _make_non_streaming_http_request

* _is_assistants_api_request

* test_openai_assistants_e2e_operations

* test_openai_assistants_e2e_operations

* openai_proxy_route

* docs openai pass through

* docs openai pass through

* docs openai pass through

* test pass through handler

* Potential fix for code scanning alert no. 2240: Incomplete URL substring sanitization

Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>

---------

Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>

litellm/proxy/pass_through_endpoints/llm_passthrough_endpoints.py

@@ -14,6 +14,7 @@ from fastapi import APIRouter, Depends, HTTPException, Request, Response
 import litellm
 from litellm.constants import BEDROCK_AGENT_RUNTIME_PASS_THROUGH_ROUTES
 from litellm.proxy._types import *
+from litellm.proxy.auth.route_checks import RouteChecks
 from litellm.proxy.auth.user_api_key_auth import user_api_key_auth
 from litellm.proxy.pass_through_endpoints.pass_through_endpoints import (
     create_pass_through_route,
@@ -405,7 +406,7 @@ async def azure_proxy_route(
             "Required 'AZURE_API_KEY' in environment to make pass-through calls to Azure."
         )
 
-    return await _base_openai_pass_through_handler(
+    return await BaseOpenAIPassThroughHandler._base_openai_pass_through_handler(
         endpoint=endpoint,
         request=request,
         fastapi_response=fastapi_response,
@@ -431,7 +432,7 @@ async def openai_proxy_route(
 
 
     """
-    base_target_url = "https://api.openai.com"
+    base_target_url = "https://api.openai.com/"
     # Add or update query parameters
     openai_api_key = passthrough_endpoint_router.get_credentials(
         custom_llm_provider="openai",
@@ -442,7 +443,7 @@ async def openai_proxy_route(
             "Required 'OPENAI_API_KEY' in environment to make pass-through calls to OpenAI."
         )
 
-    return await _base_openai_pass_through_handler(
+    return await BaseOpenAIPassThroughHandler._base_openai_pass_through_handler(
         endpoint=endpoint,
         request=request,
         fastapi_response=fastapi_response,
@@ -452,44 +453,99 @@ async def openai_proxy_route(
     )
 
 
-async def _base_openai_pass_through_handler(
-    endpoint: str,
-    request: Request,
-    fastapi_response: Response,
-    user_api_key_dict: UserAPIKeyAuth,
-    base_target_url: str,
-    api_key: str,
-):
-    encoded_endpoint = httpx.URL(endpoint).path
+class BaseOpenAIPassThroughHandler:
+    @staticmethod
+    async def _base_openai_pass_through_handler(
+        endpoint: str,
+        request: Request,
+        fastapi_response: Response,
+        user_api_key_dict: UserAPIKeyAuth,
+        base_target_url: str,
+        api_key: str,
+    ):
+        encoded_endpoint = httpx.URL(endpoint).path
 
-    # Ensure endpoint starts with '/' for proper URL construction
-    if not encoded_endpoint.startswith("/"):
-        encoded_endpoint = "/" + encoded_endpoint
+        # Ensure endpoint starts with '/' for proper URL construction
+        if not encoded_endpoint.startswith("/"):
+            encoded_endpoint = "/" + encoded_endpoint
 
-    # Construct the full target URL using httpx
-    base_url = httpx.URL(base_target_url)
-    updated_url = base_url.copy_with(path=encoded_endpoint)
+        # Ensure base_target_url is properly formatted for OpenAI
+        base_target_url = (
+            BaseOpenAIPassThroughHandler._append_v1_to_openai_passthrough_url(
+                base_target_url
+            )
+        )
 
-    ## check for streaming
-    is_streaming_request = False
-    if "stream" in str(updated_url):
-        is_streaming_request = True
+        # Construct the full target URL by properly joining the base URL and endpoint path
+        base_url = httpx.URL(base_target_url)
+        updated_url = BaseOpenAIPassThroughHandler._join_url_paths(
+            base_url, encoded_endpoint
+        )
 
-    ## CREATE PASS-THROUGH
-    endpoint_func = create_pass_through_route(
-        endpoint=endpoint,
-        target=str(updated_url),
-        custom_headers={
+        ## check for streaming
+        is_streaming_request = False
+        if "stream" in str(updated_url):
+            is_streaming_request = True
+
+        ## CREATE PASS-THROUGH
+        endpoint_func = create_pass_through_route(
+            endpoint=endpoint,
+            target=str(updated_url),
+            custom_headers=BaseOpenAIPassThroughHandler._assemble_headers(
+                api_key=api_key, request=request
+            ),
+        )  # dynamically construct pass-through endpoint based on incoming path
+        received_value = await endpoint_func(
+            request,
+            fastapi_response,
+            user_api_key_dict,
+            stream=is_streaming_request,  # type: ignore
+            query_params=dict(request.query_params),  # type: ignore
+        )
+
+        return received_value
+
+    @staticmethod
+    def _append_v1_to_openai_passthrough_url(base_url: str) -> str:
+        """
+        Appends the /v1 path to the OpenAI base URL if it's the OpenAI API URL
+        """
+        if base_url.rstrip("/") == "https://api.openai.com":
+            return "https://api.openai.com/v1"
+        return base_url
+
+    @staticmethod
+    def _append_openai_beta_header(headers: dict, request: Request) -> dict:
+        """
+        Appends the OpenAI-Beta header to the headers if the request is an OpenAI Assistants API request
+        """
+        if RouteChecks._is_assistants_api_request(request) is True:
+            headers["OpenAI-Beta"] = "assistants=v2"
+        return headers
+
+    @staticmethod
+    def _assemble_headers(api_key: str, request: Request) -> dict:
+        base_headers = {
             "authorization": "Bearer {}".format(api_key),
             "api-key": "{}".format(api_key),
-        },
-    )  # dynamically construct pass-through endpoint based on incoming path
-    received_value = await endpoint_func(
-        request,
-        fastapi_response,
-        user_api_key_dict,
-        stream=is_streaming_request,  # type: ignore
-        query_params=dict(request.query_params),  # type: ignore
-    )
+        }
+        return BaseOpenAIPassThroughHandler._append_openai_beta_header(
+            headers=base_headers,
+            request=request,
+        )
 
-    return received_value
+    @staticmethod
+    def _join_url_paths(base_url: httpx.URL, path: str) -> httpx.URL:
+        """
+        Properly joins a base URL with a path, preserving any existing path in the base URL.
+        """
+        if not base_url.path or base_url.path == "/":
+            # If base URL has no path, just use the new path
+            return base_url.copy_with(path=path)
+
+        # Join paths correctly by removing trailing/leading slashes as needed
+        base_path = base_url.path.rstrip("/")
+        clean_path = path.lstrip("/")
+        full_path = f"{base_path}/{clean_path}"
+
+        return base_url.copy_with(path=full_path)